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Climate change brings a range of challenges and opportunities to shrimp fisheries globally. The case of the Colombian Pacific Ocean (CPO) is notable due the crucial role of shrimps in the economy, supporting livelihoods for numerous families. However, the potential impacts of climate change on the distribution of shrimps loom large, making it urgent to scrutinize the prospective alterations that might unfurl across the CPO. Employing the Species Distribution Modeling approach under Global Circulation Model scenarios, we predicted the current and future potential distributions of five commercially important shrimps (Litopenaeus occidentalis, Xiphopenaeus riveti, Solenocera agassizii, Penaeus brevirostris, and Penaeus californiensis) based on an annual cycle, and considering the decades 2030 and 2050 under the Shared Socioeconomic Pathways SSP 2.6, SSP 4.5, SSP 7.0, and SSP 8.5. The Bathymetric Projection Method was utilized to obtain spatiotemporal ocean bottom predictors, giving the models more realism for reliable habitat predictions. Six spatiotemporal attributes were computed to gauge the changes in these distributions: area, depth range, spatial aggregation, percentage suitability change, gain or loss of areas, and seasonality. L. occidentalis and X. riveti exhibited favorable shifts during the initial semester for both decades and all scenarios, but unfavorable changes during the latter half of the year, primarily influenced by projected modifications in bottom salinity and bottom temperature. Conversely, for S. agassizii, P. brevirostris, and P. californiensis, predominantly negative changes surfaced across all months, decades, and scenarios, primarily driven by precipitation. These changes pose both threats and opportunities to shrimp fisheries in the CPO. However, their effects are not uniform across space and time. Instead, they form a mosaic of complex interactions that merit careful consideration when seeking practical solutions. These findings hold potential utility for informed decision-making, climate change mitigation, and adaptive strategies within the context of shrimp fisheries management in the CPO., (© 2024. The Author(s).)

The present study evaluated the effect of temporal periods of hypothermia and hyperthermia, followed by an optimal temperature recovery phase on the growth, survival, and physiological response of Penaeus vannamei. Post-larvae were exposed to stress periods for 7 and 14 days at 22 °C and 32 °C each, followed by a recovery phase at 28 °C to complete seven experimental weeks, and were compared with a control group maintained at 28 °C. Weight gain, specific growth rate, feed intake, feed conversion ratio, and survival were weekly determined. Muscle, hepatopancreas, and hemolymph were sampled on the 14th day of the recovery phase for biochemical composition, and antioxidant and digestive enzyme activities determination. The shrimp presented a higher growth rate during short-term hyperthermia in contrast to shrimp under hypothermia that presented compensatory growth after thermal stress when the temperature was restored at 28 °C. Hyperthermia increased 12-13% the feed intake while this was diminished 21-29% by the hypothermia periods. Shrimp undergo metabolic adjustments following thermal stress, with short hypothermia increasing the lipase activity and lipid storage in the hepatopancreas, while short hyperthermia also enhances chymotrypsin activity and leads to higher protein and lipid accumulation. Conversely, prolonged hyperthermia induces greater energy consumption, depleting lipid and glycogen stores, while hypothermia causes scarce mobilization of energy reserves during recovery phase. Antioxidant enzyme activities were not affected by short-thermal stress (7d), while prolonged thermal stress (14d) significantly affected SOD, CAT, and GPx activities. The present study provides important insights into the physiological plasticity of P. vannamei during recovery from thermal stress., Competing Interests: Declaration of competing interest The authors declare no competing or financial interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The cold tolerance of Litopenaeus vannamei is important for breeding in specific areas. To explore the cold tolerance mechanism of L. vannamei, this study analyzed biochemical indicators, cell apoptosis, and metabolomic responses in cold-tolerant (Lv-T) and common (Lv-C) L. vannamei under low-temperature stress (18 °C and 10 °C). TUNEL analysis showed a significant increase in apoptosis of hepatopancreatic duct cells in L. vannamei under low-temperature stress. Biochemical analysis showed that Lv-T had significantly increased levels of superoxide dismutase (SOD) and triglycerides (TG), while alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH-L), and uric acid (UA) levels were significantly decreased compared to Lv-C (p < 0.05). Metabolomic analysis displayed significant increases in metabolites such as LysoPC (P-16:0), 11beta-Hydroxy-3,20-dioxopregn-4-en-21-oic acid, and Pirbuterol, while metabolites such as 4-Hydroxystachydrine, Oxolan-3-one, and 3-Methyldioxyindole were significantly decreased in Lv-T compared to Lv-C. The differentially regulated metabolites were mainly enriched in pathways such as Protein digestion and absorption, Central carbon metabolism in cancer and ABC transporters. Our study indicate that low temperature induces damage to the hepatopancreatic duct of shrimp, thereby affecting its metabolic function. The cold resistance mechanism of Lv-T L. vannamei may be due to the enhancement of antioxidant enzymes and lipid metabolism., (© 2024. The Author(s).)

This study looked at the effects of adding butyric acid (BA) to the diets of juvenile Pacific shrimp and how it affected their response to survival, immunity, histopathological, and gene expression profiles under heat stress. The shrimp were divided into groups: a control group with no BA supplementation and groups with BA inclusion levels of 0.5 %, 1 %, 1.5 %, 2 %, and 2.5 %. Following the 8-week feeding trial period, the shrimp endured a heat stress test lasting 1 h at a temperature of 38 °C. The results showed that the control group had a lower survival rate than those given BA. Interestingly, no mortality was observed in the group receiving 1.5 % BA supplementation. Heat stress had a negative impact on the activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in the control group. Still, these activities were increased in shrimp fed the BA diet. Similar variations were observed in AST and ALT fluctuations among the different groups. The levels of triglycerides (TG) and cholesterol (CHO) increased with high temperatures but were reduced in shrimp-supplemented BA. The activity of an antioxidant enzyme superoxide dismutase (SOD) increased with higher BA levels (P < 0.05). Moreover, the groups supplemented with 1.5 % BA exhibited a significant reduction in malondialdehyde (MDA) content (P < 0.05), suggesting the potential antioxidant properties of BA. The histology of the shrimp's hepatopancreas showed improvements in the groups given BA. Conversely, the BA significantly down-regulated the HSPs and up-regulated MnSOD transcript level in response to heat stress. The measured parameters determine the essential dietary requirement of BA for shrimp. Based on the results, the optimal level of BA for survival, antioxidant function, and immunity for shrimp under heat stress is 1.5 %., Competing Interests: Declaration of competing interest It is asserted by the authors that there were no conflicts of interest in this experiment., (Copyright © 2024. Published by Elsevier Ltd.)

The widespread occurrence of nanoplastic (NP) pollution in the environment is a growing concern, and its presence poses a potential threat to cultured aquatic animals. Previously, we found that NPs can significantly affect the lipid metabolism of shrimp. However, relevant reports about the effects of increasing dietary lipid levels on NP toxicity are lacking. Therefore, we explored the effects of dietary supplementation with different lipid levels on the growth and lipid metabolism of Pacific white shrimp (Litopenaeus vannamei). We cultured L. vannamei at three dietary lipid levels (3 %, 6 %, and 9 %) and three NP concentrations (0, 1, and 3 mg/L) for 2 months. We evaluated the effects of lipid levels on growth indexes, hepatopancreas morphological structure, lipid metabolism-related enzyme activity, and gene expression of the shrimp. The results showed that as lipid intake increased, the survival rate, body weight growth rate, and hepatosomatic ratio of the shrimp increased while the feed conversion rate decreased. Additionally, the crude protein and crude lipid contents increased, whereas the moisture and ash contents did not change much. We found that the morphological structure of the hepatopancreas was seriously damaged in the 3 mg/L NPs and 3 % dietary lipid group. Finally, lipid metabolism-related enzyme activities and gene expression levels increased with increased dietary lipid levels. Together, these results suggest that increasing dietary lipid content can improve shrimp growth and alleviate lipid metabolism disorders caused by NPs. This study is the first to show that nutrition regulation can alleviate the toxicity of NPs, and it provides a theoretical basis for the green and healthy culture of L. vannamei., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Dietary lipid supplementation alleviated the impacts of polystyrene nanoplastic exposure in Litopenaeus vannamei”., (Copyright © 2024. Published by Elsevier B.V.)

Environmental stressors in aquatic organisms can be assessed using a bioenergetic approach based on the evaluation of changes in their physiological parameters. We evaluated the chronic effects of cadmium (Cd 2+ ) on the energy balance as well as the survival, growth, metabolism, nitrogen excretion, hepatosomatic index, oxidized energy substrate, and osmoregulation of the shrimp Penaeus vannamei with the hypothesis that the high energy demand related to the homeostatic regulation of Cd 2+ could disrupt the energy balance and as a consequence, their physiological functions. The shrimp exposed to Cd 2+ had higher mortality (30%), directed more energy into growth (33% of energy intake), ingested 10% more energy, and defecated less than control animals. Cd 2+ exposure caused a tendency to decrease metabolism and ammonia excretion but did not alter the hepatosomatic index, type of energy substrate oxidized, and the hyperosmorregulatory pattern of the species. The Cd +2 exposure may have induced a trade-off response because there was a growth rate increase accompanied by increased mortality., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Growing concerns have emerged over the combined effects of multiple stressors on ecosystems. Empirical evidence shows that the sensitivity of aquatic invertebrates to insecticides varies under thermally fluctuating conditions. Additionally, field surveys in estuarine areas of western Japan confirmed the presence of juvenile kuruma prawns (Penaeus japonicus) carrying the white spot syndrome virus (WSSV). Given the potential of co-exposure to multiple stressors, we performed a combined exposure experiment using a full-factorial design with three stressors: WSSV infection (presence or absence: initial 2 h exposure), fipronil (insecticide) exposure (0 or 0.1 μg/L: 14 d exposure), and temperature (20, 25, or 30 °C). We observed the highest mortality (75 %) in the WSSV + Fipronil treatment at 30 °C, with the associated specimens showing significant changes in the internal load of WSSV and concentrations of fipronil and its metabolite, fipronil sulfone. Severe perturbations of metabolites associated with increased energy expenditure and fatty acid utilization have been identified as potential factors underlying lethality in juvenile kuruma prawns. The results demonstrate that WSSV infection increases the susceptibility of thermally stressed juvenile kuruma prawns to fipronil. Therefore, further studies are required to determine the combined effects of multiple stressors in environmentally relevant scenarios on juvenile kuruma prawns as well as in estuarine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In light of increasing concerns about microplastic pollution, it is crucial to understand the biological impacts of biodegradable PHB microplastics on marine organisms. This study included a 96-h exposure experiment to assess acute toxicity at PHB concentrations of 0 mg/L, 100 mg/L, 500 mg/L and 1000 mg/L. Additionally, a 60-day feeding trial was conducted with PHB concentrations of 0, 0.5, 1.0 and 2.0 g/kg to evaluate the long-term effects on growth, physiological health and metabolic responses of Litopenaeus vannamei. Results from the exposure experiment indicated that PHB microplastics up to 100 mg/L were non-toxic to shrimp. However, the 60-day feeding trial revealed that higher concentrations led to slight reductions in survival rates and growth performance, indicating a concentration-dependent response. Analysis of antioxidant and immune enzymes showed minimal changes across most parameters. However, increases in malondialdehyde content and lysozyme activity at higher PHB levels suggested a stress response. Microbial analysis indicated higher species richness and greater community diversity in the PHB group compared to controls, as evidenced by Chao1, ACE, Shannon and Simpson indices. Linear discriminant analysis revealed that Enterobacteriales and related taxa were more prevalent in the PHB group, while Rhodobacteraceae and associated taxa dominated the control group. Pathway analysis highlighted enhanced signal transduction, cell mobility and metabolic resource reallocation in response to PHB-induced stress. Integrated transcriptomic and metabolomic analyses revealed significant regulatory changes, especially in lipid metabolism pathways. These findings suggest that while PHB microplastics trigger adaptive metabolic responses in shrimp, they do not cause acute toxicity. Significant variations in intestinal microbiome composition reflect potential shifts in gut health dynamics due to PHB ingestion. This study enhances our understanding of the ecological impacts of microplastics and underscores the necessity for further research into the environmental safety of biodegradable alternatives., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Increasing attention is being paid to the toxic physiological effects of nanoplastics (NPs) on aquatic organisms. However, few studies have systematically evaluated the regulatory mechanisms of NPs on immune response in crustaceans. In this study, a 28-day chronic exposure experiment was conducted in which shrimps were exposed to various 80-nm polystyrene NPs concentrations (0, 0.1, 1, 5 and 10 mg/L). Transcriptomic analysis was used to investigate the regulatory mechanisms of NPs in immune response of Litopenaeus vannamei. With increasing NPs concentration, the total hemocyte count (THC) content decreased, while phagocytosis rate (PR) and respiratory burst (RB) showed trends of first rising and then falling. High concentration (10 mg/L) of NPs caused the destruction of hepatopancreas tissue structure, the shedding of microvilli, the increase number of hepatocyte apoptosis and autophagy structure. With increasing NPs concentration, the lysozyme (Lys), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities first increased and then decrease, while contents of lipid peroxidation and malondialdehyde increased; the expression levels of Toll, MyD88, GPx, SOD, proPO, Lys, and ALF generally increased at first and then decreased. Transcriptional sequencing analysis showed that the pathway of differentially expressed genes in KEGG enrichment mainly included lysosome (ko04142), apoptosis (ko04210) pathways, indicating that the NPs mainly affected the immune regulatory mechanism. Further analysis by Gene Set Enrichment Analysis (GSEA) showed that the up-regulation pathways of NPs activation mainly included immune response-related pathways such as mitochondrial autophagy, DNA repair, autophagosomes signaling pathway. Our results indicated that NPs exposure induced oxidative stress, apoptosis and autophagy in shrimps. This study provides a basis for further understanding of the mechanisms of antioxidant immune regulation by NPs in shrimp and may serve as a reference for healthy ecological culture of shrimp., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Transcriptomic analysis reveals nanoplastic-induced apoptosis, autophagy and immune response in Litopenaeus vannamei”., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In the present study, the effect of temperature shock (sudden and gradual) by increasing water temperature from 28 °C to 40 °C on survival, behavioral responses and immunological changes in Litopenaeus vannamei (L. vannamei) was studied. In sudden temperature shock, experimental groups were maintained at different temperature ranges such as 28 °C- 31 °C; 28 °C-34 °C; 28 °C-37 °C and 28 °C-40 °C along with 28 °C as control. For gradual temperature shock experiments, the initial water temperature was maintained at 28 °C for 24 h in control and then increased to 1 °C for every 24 h until reaching 40 °C. On reaching the final temperature of 40 °C, it was kept stable for 120 h. Results indicated that the increasing water temperature (sudden shock) affected survival, behavioral responses and immunological parameter. No shrimp survived at 40 °C treatment (sudden), whereas in the gradual temperature shock experiment 20% of animals survived at 40 °C. The increasing water temperature had no effects on behavioral responses up to 37 °C (gradual), but at 40 °C the observation of muscle cramps, low swimming rate, no feeding, muscle and hepatopancreas color turned whitish. Overall, the results suggest that L. vannamei can tolerate water temperature up to 34 °C under sudden shock and 37 °C under gradual shock conditions. This study reveals that shrimp L. vannamei can self-regulate to a certain extent of temperature variation in the environment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Biofloc (BF) stands out as a promising system for sustainable shrimp farming. Optimizing various culture conditions, such as stocking density, carbohydrate source, and feeding management, is crucial for the widespread adoption of the BF system. This study compares the growth performance of white-leg shrimp (Litopenaeus vannamei) in culture ponds at low density (LD) with 50 organisms/m 2 and high density (HD) with 200 organisms/m 2 . Post-larvae of white-leg shrimp were stocked for 16 weeks in both LD and HD groups. The LD group exhibited a superior survival rate, growth rate, and feed consumption compared to the HD group. The BF from the LD system recorded a significantly higher protein content (16.63 ± 0.21%) than the HD group (15.21 ± 0.34%). Heterotrophic bacterial counts in water did not significantly differ with stocking density. However, Vibrio count in water samples was higher in the HD group (3.59 ± 0.35 log CFU/mL) compared to the LD group (2.45 ± 0.43 log CFU/mL). The whole shrimp body analysis revealed significantly higher protein and lipid content in the LD group. In contrast, the total aerobic bacterial count in shrimp from the HD group was high, with the identification of Salmonella enterica ssp. arizonae. Additionally, Vibrio counts in shrimp samples were significantly higher in the HD group (4.63 ± 0.32 log CFU/g) compared to the LD group (3.57 ± 0.22 log CFU/g). The expression levels of immune-associated genes, including prophenoloxidase, transglutaminase, penaiedin 3, superoxide dismutase, lysozyme, serine proteinase, and the growth-related gene ras-related protein (rap-2a), were significantly enhanced in the LD group. Conversely, stress-related gene expression increased significantly in the HD group. Hepatopancreases amylase, lipase, and protease were higher in the LD group, while trypsin activity did not differ significantly. Antioxidant enzyme activity (catalase, glutathione, glutathione peroxidase, and superoxide dismutase) significantly increased in the LD group. The histological structure of hepatopancreas, musculature, and female gonads remained similar in both densities. However, negative effects were observed in the gills' histology of the HD group. These results suggest that increasing stocking density is associated with significantly negative biological, microbial, and physiological effects on white-leg shrimp under the BF system., (© 2024. The Author(s).)

Shrimp fry counting is an important task for biomass estimation in aquaculture. Accurate counting of the number of shrimp fry in tanks can not only assess the production of mature shrimp but also assess the density of shrimp fry in the tanks, which is very helpful for the subsequent growth status, transportation management, and yield assessment. However, traditional manual counting methods are often inefficient and prone to counting errors; a more efficient and accurate method for shrimp fry counting is urgently needed. In this paper, we first collected and labeled the images of shrimp fry in breeding tanks according to the constructed experimental environment and generated corresponding density maps using the Gaussian kernel function. Then, we proposed a multi-scale attention fusion-based shrimp fry counting network called the SFCNet. Experiments showed that our proposed SFCNet model reached the optimal performance in terms of shrimp fry counting compared to CNN-based baseline counting models, with MAEs and RMSEs of 3.96 and 4.682, respectively. This approach was able to effectively calculate the number of shrimp fry and provided a better solution for accurately calculating the number of shrimp fry.

Background: A commercially significant species in the aquaculture sector globally, particularly in Egypt, is Litopenaeus vannamei., Aim: The experiment's objective was to ascertain how Sanolife PRO-F impacted the growth, water quality, immunological response, and intestinal morphometry of L. vannamei ., Methods: In the current investigation, which lasted 12 weeks, Sanolife PRO-F was administered to shrimp post-larvae at diet doses of 0 (control), 1 (group one), 2 (group two), and 3 (group three) g/kg diet, respectively. Each experimental group had three repetitions., Results: In the current study, shrimp fed on probiotic-treated diets showed a considerable improvement in growth performance measures and survival rate, and the nonspecific immune response was also enhanced. Shrimp fed probiotic diets had longer and more intestinal villi overall. Shrimp fed on the G2 and G3 diets showed no appreciable differences in growth or intestinal morphology. With the G2 and G3 diet, the water had lower concentrations of nitrite and ammonia., Conclusion: The study's findings indicate that Sanolife PRO-F treatment at 2-3 g/kg feed promotes the growth of shrimp, immunological response, gut health and function, and water quality.

Agricultural and anthropogenic activities release high ammonia levels into aquatic ecosystems, severely affecting aquatic organisms. Penaeid shrimp can survive high ammonia stress conditions, but the underlying molecular mechanisms are unknown. Here, total hemocyanin and oxyhemocyanin levels decreased in Penaeus vannamei plasma under high ammonia stress. When shrimp were subjected to high ammonia stress for 12 h, 24 hemocyanin (HMC) derived peptides were identified in shrimp plasma, among which one peptide, designated as HMCs27, was chosen for further analysis. Shrimp survival was significantly enhanced after treatment with the recombinant protein of HMCs27 (rHMCs27), followed by high ammonia stress. Transcriptome analysis of shrimp hepatopancreas after treatment with or without rHMCs27 followed by high ammonia stress revealed 973 significantly dysregulated genes, notable among which were genes involved in oxidation and metabolism, such as cytochrome C, catalase (CAT), isocitrate dehydrogenase, superoxide dismutase (SOD), trypsin, chymotrypsin, glutathione peroxidase, glutathione s-transferase (GST), and alanine aminotransferase (ALT). In addition, levels of key biochemical indicators, such as SOD, CAT, and total antioxidant capacity (T-AOC), were significantly enhanced, whereas hepatopancreas malondialdehyde levels and plasma pH, NH 3 , GST, and ALT levels were significantly decreased after rHMCs27 treatment followed by high ammonia stress. Moreover, high ammonia stress induced hepatopancreas tissue injury and apoptosis, but rHMCs27 treatment ameliorated these effects. Collectively, the current study revealed that in response to high ammonia stress, shrimp generate functional peptides, such as peptide HMCs27 from hemocyanin, which helps to attenuate the ammonia toxicity by enhancing the antioxidant system and the tricarboxylic acid cycle to decrease plasma NH 3 levels and pH., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yueling Zhang and Jude Juventus Aweya reports article publishing charges and equipment, drugs, or supplies were provided by National Natural Science Foundation of China. Yueling Zhang reports article publishing charges and equipment, drugs, or supplies were provided by Natural Science Foundation of Guangdong., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Microcystins (MCs) are biologically active cyclic heptapeptide compounds released by cyanobacteria in water bodies, and MC-LR is one of the most widespread and toxic isoforms. It frequently poses a serious threat to Penaeus vannamei aquaculture. Our previous study revealed that the supplementation of Lactobacillus plantarum Ep-M17 has a probiotic effect on P. vannamei health and whether Ep-M17 can alleviate the stressful effects of MC-LR on shrimp remains unclear. Therefore, in the present work, shrimp were fed MC-LR alone or combined with Ep-M17 for six weeks, and then evaluated the effects on histology, enzyme activity, gene expression, and intestinal flora. The results showed that MC-LR stress lead to slow growth and reduced survival rates in shrimp. However, feeding Ep-M17 significantly increased both the growth rate and survival rate. Meanwhile, MC-LR stress caused severe tissue damage in the hepatopancreas and intestines of shrimp, but Ep-M17 significantly reduced the toxic effects and protected the integrity of these tissues. Additionally, Ep-M17 significantly enhanced the activities of antioxidant enzymes and digestive enzymes, and induced higher expression of immune-related genes, thereby promoting the digestive and immune responses in shrimp. Furthermore, MC-LR stress disrupted the intestinal flora in shrimp intestines, while the use of Ep-M17 significantly increased the abundance of immune- and metabolism-related bacteria and inhibited the growth of pathogenic bacteria to maintain intestinal flora balance and intestinal health. In conclusion, our results indicate that Ep-M17 can reduce the toxic effect of MC-LR on shrimp and has a positive function in the prevention and control of shrimp diseases caused by MC-LR., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Cigarette butts (CB) are a source of microfibers (MFs) in aquatic environments, posing a risk to the health of aquatic organisms. Research has been focused on examining the toxicity of CBs on ecological receptors, including invertebrates. More focus has been on death, growth, or movement inhibition of but less on exoskeletal effects in malacostracans. We evaluated the alteration in the carapace structure of whiteleg shrimp (Penaeus vannamei Boone, 1931) caused by MFs derived from CBs (CB-MF). Exposure to CB-MF damaged the gills, the main organs adsorbing calcium in shrimps to generate a hard carapace, disturbing calcium uptake via respiration. Rapid ecdysis caused on CB-MF exposure reduced the environmental adaptation capacity of crustaceans in the absence of normal pigments in the chromatophore of the carapace. These findings indicate that MFs released from CBs released into the aquatic environment can adversely affect exoskeletal alteration within the overall ecosystem., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Plastics are widely produced for industrial and domestic applications due to their unique properties, and studies on the toxic effects of nanoplastics (NPs) on aquatic animals are essential. In this study, we investigated the transcriptomic patterns of Litopenaeus vannamei after NPs exposure. We found that the lysosome pathway was activated when after NPs exposure, with up-regulated DEGs, including glucocerebrosidase (GBA), hexosaminidase A (HEXA), sphingomyelin phosphodiesterase-1 (SMPD1), and solute carrier family 17 member 5 (SLC17A5). In addition, the PI3K-Akt signaling pathway was strongly affected by NPs, and the upstream genes of PI3K-Akt, including epidermal growth factor receptor (EGFR), integrin subunit beta 1 (ITGB1) and heat shock protein 90 (HSP90) were up-regulation. Other genes involved in lipogenesis, such as sterol regulatory element binding transcription factor 1 (SREBP-1c), fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD-1), were down-regulated. However, the contents of triglycerides (TG) and total cholesterol (TCH) in L. vanname hepatopancreas were reduced, which indicated that the ingestion of NPs led to the disturbance of hepatic lipid metabolism. What more, NPs treatment of L. vannamei also caused oxidative stress. In addition, NPs can damage part of the tissue structure and affect the physiological function of shrimps. The results of this study provide valuable ecotoxicological data to improve the understanding of the biological fate and effects of nanoplastics in L. vannamei., (Copyright © 2023. Published by Elsevier Ltd.)

4-Nonylphenol (4-NP) is one of the common endocrine-disrupting chemicals (EDCs) in estuaries and coastal zones, which can exert detrimental effects on the physiological function of aquatic organisms. However, the molecular response triggered by 4-NP remains largely unknown in Pacific white shrimp (Litopenaeus vannamei). In this study, transcriptomic analysis was performed to investigate the underlying mechanisms of 4-NP toxicity in the hepatopancreas of L. vannamei. Nine RNA-Seq libraries were generated from L. vannamei at 0 h, 24 h, and 48 h following exposure to 4-NP. Compared with 0 h vs 24 h, 962 up- and 463 down-regulated differentially expressed genes (DEGs) were identified, indicating that many genes in L. vannamei were induced to resist adverse circumstances by 4-NP exposure. In contrast, 902 up- and 1027 down-regulated DEGs were revealed in the comparison of 0 h vs 48 h, demonstrating that prolonged exposure to the stress from 4-NP resulted in more inhibited genes. To validate the accuracy of the transcriptome data, eight DEGs were selected for quantitative real-time polymerase chain reaction (qRT-PCR), which were consistent with the RNA-Seq results. Through KEGG pathway enrichment analysis, three specific pathways related to hormonal effects and endocrine function of L. vannamei were enriched significantly, including tyrosine metabolism, insect hormone biosynthesis, and melanogenesis. After 4-NP stress, genes involved in tyrosine metabolism (Tyr) and melanogenesis pathway (AC, CBP, Wnt, Frizzled, Tcf, and Ras) were induced to promote melanin pigment to help shrimp resist adverse environments. In the insect hormone biosynthesis, ALDH, CYP15A1, CYP15A1/C1, and JHE genes were activated to synthesize juvenile hormone (JH), while Spook, Phm, Sad, and CYP18A1 were induced to generate molting hormone. There is an enhanced interaction between the molting hormone and JH, with JH playing a dominant role and maintaining its "classic status quo action". Our study demonstrated that 4-NP exposure led to impairments of biological functions in L. vannamei hepatopancreas. The genes and pathways identified provide novel insights into the molecular mechanisms underlying 4-NP toxicity effects in prawns and enrich the information on the toxicity mechanism of crustaceans in response to EDCs exposure., Competing Interests: Declaration of competing interest No conflict of interest exists in the submission of this manuscript, and the manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously and is not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Immunotoxicity of silver nanoparticles (AgNPs) to whiteleg shrimp (Litopenaeus vannamei) was assessed using redox-status orchestrating enzymes. To this end, the shrimp was exposed to sublethal AgNPs concentrations (0 % LC 50 : control; 25 % LC 50 : 0.97 mg/L; 50 % LC 50 : 1.95 mg/L; 75 % LC 50 : 2.92 mg/L). During the experiment, the behavior of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx) was monitored, besides total antioxidant capacity (TAC) and malondialdehyde (MDA). The hepatopancreas SOD activity reduced about 63 %-76 % at.%50 LC 50 and %75 LC 50 AgNPs treatments, and CAT decreased in both tissues at 50 % LC 50 AgNPs. TAC exhibited a U-form response in the hepatopancreas organ against stress caused by AgNPs, and hepatopancreas MDA displayed a time-dependent increase. Taken together, AgNPs triggered severe immunotoxicity through suppression of CAT, SOD, and TAC in the hepatopancreas tissue., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In aquatic environments, rising temperatures reduce the oxygen content of the water while increasing the oxygen demand of organisms. In intensive shrimp culture, it is of great importance to know the thermal tolerance of cultured species and their oxygen consumption since this affects the physiological condition. In this study, the thermal tolerance of Litopenaeus vannamei was determined by dynamic and static thermal methodologies at different acclimation temperatures (15, 20, 25, and 30 °C) and salinities (10, 20, and 30 ppt). The oxygen consumption rate (OCR) was also measured to determine the standard metabolic rate (SMR) of shrimp. Acclimation temperature significantly affected the thermal tolerance and SMR of Litopenaeus vannamei (P < 0.01). Salinity had a large effect on SMR (P < 0.01) but did not influence the thermal acclimation of the shrimp (P > 0.01). Litopenaeus vannamei is a species that has high thermal tolerance and can survive at extreme temperatures (CT min -CT max : 7.2-41.9 °C) with its large dynamic (988, 992, and 1004 °C 2 ) and static thermal polygon areas (748, 778 and 777 °C 2 ) developed at the above temperature and salinity combinations and resistance zone (1001, 81 and 82 °C 2 ). The optimal temperature range of Litopenaeus vannamei is the 25-30 °C range, where a decrease in standard metabolism is determined with increasing temperature. Given the SMR and optimal temperature range, the results of this study indicate that Litopenaeus vannamei should be cultured at 25-30 °C for effective production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The Penaeus vannamei is an important shrimp species with enormous commercial and ecological values. In production process, the air exposure resistance is vital for live transportation without water. We tested the air exposure resistant ability of P. vannamei, and carried out gill histological observation and gene expression analysis. The physiology and molecular response to the air exposure stress of P. vannamei was revealed. We found that body weight could affect the air exposure tolerance. Air exposure caused epithelial cell of gill filament shrinking and tissue fluid exudation within half of hour, and triggered oxidative stress response. After retrieved to water, epithelial cell shrinking and tissue fluid exudation recovered gradually, but oxidative and antioxidant response is still going on. Organisms reduced oxidative stress by regulating levels of antioxidants and antioxidant enzymes that remove reactive oxygen species (ROS) and RNA and DNA processing to repair tissue damage, and expression of apoptosis associated-genes altered. Furthermore, the survive shrimps could live steadily more than 5 days, and their gill filament recovered to normal state, proving that the damage of air exposure is reversible. These findings could be considered in the waterless live transportation of P. vannamei., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Raw materials for making dried shrimp (a type of foodstuff) are mostly from farmed shrimp and preliminary findings indicated that head copper (Cu) concentrations in some commercial dried shrimp products exceeded the safe limit specified in pollution-free aquatic products (50 mg/kg), which may influence food safety. Therefore, a 63-day feeding trial was conducted to explore effects of dietary Cu concentrations on accumulation of Cu in tissues, growth performance, immune response and antioxidant status of Pacific white shrimp (Litopenaeus vannamei). Moderating effect of myo-inositol (MI, adding 200 mg/kg diet) on the adverse impacts caused by excessive dietary Cu was also investigated. 600 shrimp (initial weight: 0.89 ± 0.00 g) were divided into five groups: 37.08 mg Cu/kg diet group (control group), 62.57 mg Cu/kg diet group, 125.99 mg Cu/kg diet group, 63.41 mg Cu/kg diet group (supplemented with MI) and 119.19 mg Cu/kg diet group (supplemented with MI). The results showed that dietary Cu concentrations increased from 37.08 to over 62.57 mg/kg, hepatopancreas Cu concentrations raised from 29.04 to 233.43-263.65 mg/kg, and muscle Cu concentrations only increased from 6.22 to 6.99-8.39 mg/kg. Report to control group, excessive Cu concentration (125.99 mg/kg) didn't significantly affect growth performance, but it notably reduced whole body lipid content and immune response, induced oxidative stress and damaged the hepatopancreas structure, which was ameliorated by MI supplementation. The results suggested that consuming shrimp head and its processed products weren't recommended. Cu concentrations of commercial feeds for Pacific white shrimp should be controlled below 62.57 mg/kg. Additionally, MI supplementation mitigated the negative impacts induced by excessive dietary Cu., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Nuclear factor E2-related factor 2 (Nrf2) is a multifunctional transcription factor that plays an important role in antioxidant activities. However, its effect on antioxidant capacity in Litopenaeus vannamei, an economically important crustacean, remains unclear. In this study, the role of Nrf2 in response to oxidative stress in L. vannamei was determined by its effect on relevant gene expression and enzymatic activity. Nrf2 was cloned and analyzed. Results revealed that Nrf2 contains a 1575 bp open reading frame encoding 524 amino acids and a conserved bZIP Maf domain. The sequence similarity of Nrf2 between L. vannamei and Homarus americanus is 81%. Although the Nrf2 expression was detected in all tissues, the Nrf2 expression levels were the highest in the hepatopancreas, followed by the eyestalk and muscle. RNA interference significantly decreased the expression of antioxidant-related genes (SOD, GPX, CAT, Trx, and HO-1; p < 0.05), significantly upregulated the expression of autophagy genes (Atg3, Atg4, Atg5, Atg10, and Atg12; p < 0.05) and apoptosis genes (Caspase-3 and P53; p < 0.05). Moreover, SOD, CAT, and GPX enzyme activities decreased whereas the MDA activity increased. The histological results of the shrimp injected with dsRNA-Nrf2 showed that the hepatic tubules were irregularly arranged, the lumen was abnormal, and a few hepatic tubules were significantly enlarged compared with those of the dsRNA-EGFP group. The hepatocytes were also vacuolated. In conclusion, this study provided evidence that Nrf2 is involved in the regulation of antioxidant capacity, oxidative stress, apoptosis, and autophagy in shrimp., (Copyright © 2022. Published by Elsevier Ltd.)

Nitrite stress is a major environmental factor that limits aquatic animal growth, reproduction and survival. Even so, some shrimps still can withstand somewhat high concentrations of nitrite environment. However, few studies have been conducted about the tolerance molecular mechanism of Litopenaeus vannamei in the high concentration nitrite. To identify the genes and pathways involved in the regulation of nitrite tolerance, we performed comparative transcriptomic analysis in the L. vannamei nitrite-tolerant (NT) and nitrite-sensitive (NS) families, and untreated shrimps were used as the control group. After 24 h of nitrite exposure (NaNO 2 , 112.5 mg/L), a total of 1521 and 868 differentially expressed genes (DEGs) were obtained from NT compared with NS and control group, respectively. Functional enrichment analysis revealed that most of these DEGs were involved in immune defense, energy metabolism processes and endoplasmic reticulum (ER) stress. During nitrite stress, energy metabolism in NT was significantly enhanced by activating the related genes expression of oxidative phosphorylation (OXPHOS) pathway and tricarboxylic acid (TCA) cycle. Meanwhile, some DEGs involved in innate immunity- related genes and pathways, and ER stress responses also were highly expressed in NT. Therefore, we speculate that accelerated energy metabolism, higher expression of immunity and ER related genes might be the important adaptive strategies for NT in relative to NS under nitrite stress. These results will provide new insights on the potential tolerant molecular mechanisms and the breeding of new varieties of nitrite tolerant L. vannamei., (Copyright © 2021. Published by Elsevier Inc.)

Unfavorable conditions severely affect the survival quality of Litopenaeus vannamei (L. vannamei) during live transport and the molecular response mechanism needs to be clarified. In this study, metabolomics combined with conventional assay on physiological and histopathological responses were applied to deepen the understanding of L. vannamei to cold stress and provide. A solid foundation for regulation of transportation management. Physiological and biochemical analysis revealed the significant disturbance of glycolysis in hepatopancreas tissue. Furthermore, metabolomics based on the technique of ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry identified the significantly differential metabolites between acute cold exposure (AC) and normal control (NC) groups. Moreover, KEEG result indicated that the pathways of amino acid, glycerophospholipid, and nuclei acid metabolism and ABC transporters in hepatopancreas were significantly disturbed. Furthermore, histopathology and ultrastructure verified the impairment in hepatopancreas during cold stress. Overall, the concurrent use of metabolomics and biochemical assays was demonstrated to be sensitive and effective in providing new insights into the response mechanism of L. vannamei to cold stress., (Copyright © 2022. Published by Elsevier Ltd.)

Maintaining the homeostasis of energy metabolism is crucial for organism's stress tolerance and survival. Acute cold exposure (AC) and waterless duration (WD) represent the two predominate abiotic stressors during waterless live transport of Litopenaeus vannamei. Although previous reports have explored the physiological response of L. vannamei to combined stress AC + WD, the roles of energy metabolism response in regulation of stress tolerance remains unknown. The present study comparatively examined the variations of energy metabolism-related indicators in hemolymph (cortisol, hemocyanin, glucose and lactate), hepatopancreas and muscle tissues (levels of lactate and glycogen, activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase), and ATP levels). Combined stress significantly disturbed the homeostasis of energy metabolism with the increase in levels of hemocyanin, glucose and lactate, and decrease in glycogen and ATP content (P < 0.05). In addition, the activities of HK, PFK, PK, and SDH initially elevated and then decreased with the prolongation of combined stress from 3h to 9h duration, while the activity of lactate dehydrogenase (LDH) remained gradual elevation and ATPase activity decreased in a duration time dependent manner throughout the experiment. These alterations revealed that exposure to combined stress could accelerate anaerobic metabolism at initial stage and inhibit aerobic metabolism in a duration time-dependent manner, following with the reduction of energy biosynthesis and the disturbance of energy metabolism equilibrium. On the other hand, the progressive impairment on hepatopancreas tissue was observed under combined stress. In summary, the deficiency of ATP supply and histopathological injures on hepatopancreas tissue might the underlying mechanisms inducing mortality of L. vannamei during live transport., (Copyright © 2021. Published by Elsevier Ltd.)

Interferon regulatory factors (IRFs) are transcription factors found in both vertebrates and invertebrates that were recently identified and found to play an important role in antiviral immunity in black tiger shrimp Penaeus monodon . In this study, we investigated the mechanism by which P. monodon IRF ( Pm IRF) regulates the immune-related genes downstream of the cytosolic DNA sensing pathway. Depletion of Pm IRF by double-stranded RNA-mediated gene silencing significantly reduced the mRNA expression levels of the IFN-like factors Pm Vago1, Pm Vago4, and Pm Vago5 and antilipopolysaccharide factor 6 (ALF Pm 6 ) in shrimp. In human embryonic kidney (HEK293T) cells transfected with Pm IRF or co-transfected with DEAD-box polypeptide ( Pm DDX41) and simulator of IFN genes ( Pm STING) expression plasmids, the promoter activity of IFN-β, nuclear factor (NF-κB), and ALF Pm 6 was synergistically enhanced following stimulation with the nucleic acid mimics deoxyadenylic-deoxythymidylic acid sodium salt [poly(dA:dT)] and high molecular weight (HMW) polyinosinic-polycytidylic acid [poly(I:C)]. Both nucleic acid mimics also significantly induced Pm STING, Pm IRF, and ALF Pm 6 gene expression. Co-immunoprecipitation experiments showed that Pm IRF interacted with Pm STING in cells stimulated with poly(dA:dT). Pm STING, Pm IRF, and Pm DDX41 were localized in the cytoplasm of unstimulated HEK293T cells and Pm IRF and Pm DDX41 were translocated to the nucleus upon stimulation with the nucleic acid mimics while Pm STING remained in the cytoplasm. These results indicate that Pm IRF transduces the pathogen signal via the Pm DDX41- Pm STING DNA sensing pathway to induce downstream production of interferon-like molecules and antimicrobial peptides., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Soponpong, Amparyup, Kawai and Tassanakajon.)

Managing the reproduction of shrimp farmed in captivity is essential for selective breeding and interspecies hybridization. Procedures have not been developed for conducting in vitro fertilization in penaeid shrimp. In this study, the feasibility of in vitro fertilization (IVF) of the pre-ovulatory oocyte of Penaeus indicus was examined. Additionally, the processes of fertilization and possibility of hybridizing P. indicus with P. monodon with utilization of IVF procedures was also evaluated. The IVF was conducted by dissecting ovaries with fully developed follicles, and mixing these (~0.1 million oocytes) with 1 mL of a sperm suspension. Evaluations for fertilization and embryonic development occurred every l5 min. The eggs collected from the ovaries had the capacity for activation and fertilization. The hatching rate was 5.5 ± 1.1% of the total number of eggs fertilized, and 8.2 ± 4.8% of the nauplii developed to the post-larval stage. Results from the scanning electron micrograph evaluations provided detailed information about the changes occurring as a result of IVF in P. indicus. Interspecific hybridization of P. indicus with P. monodon did not result in hatching of embryos from the eggs, although 1% of eggs were fertilized. A reliable and inexpensive IVF procedure was developed, therefore, IVF could be an efficacious procedure for facilitation of intraspecific cross production in a penaeid breeding program. Furthermore, it was determined that IVF could be a possible procedure for interspecies hybridization between closely related species to circumvent prezygotic barriers in reproductive processes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

White Spot Syndrome Virus (WSSV) causes White Spot Disease (WSD) and is historically the most devastating disease in the shrimp industry. Global losses from this disease have previously exceeded $3 bn annually, having a major impact on a global industry worth US$19 bn per annum. Shrimp are cultured predominantly in enclosed ponds that are subject to considerable fluctuations in abiotic conditions and WSD outbreaks are increasingly linked to periods of extreme weather, which may cause major fluctuations in pond culture conditions. Combined with the intensity of production in these systems, the resulting suboptimal physicochemical conditions have a major bearing on the susceptibility of shrimp to infection and disease. Current knowledge indicates that pond temperature and salinity are major factors determining outbreak severity. WSSV appears to be most virulent in water temperatures between 25 and 28 °C and salinities far removed from the isoosmotic point of shrimp. Elevated temperatures (>30 °C) may protect against WSD, depending on the stage of infection, however the mechanisms mediating this effect have not been well established. Other factors relating to water quality that may play key roles in determining outbreak severity include dissolved oxygen concentration, nitrogenous compound concentration, partial pressure of carbon dioxide and pH, but data on their impacts on WSSV susceptibility in cultured shrimps is scarce. This illustrates a major research gap in our understanding of the influence of environmental conditions on disease. For example, it is not clear whether temperature manipulations can be used effectively to prevent or mitigate WSD in cultured shrimp. Therefore, developing our understanding of the impact of environmental conditions on shrimp susceptibility to WSSV may provide insight for WSD mitigation when, even after decades of research, there is no effective practical prophylaxis or treatment., (Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.)

Many crustaceans produce sounds that might be used in communication. However, little is known about sound detection in crustaceans, hindering our understanding of crustacean acoustic communication. Sound detection has been determined only for a few species, and for many species, it is unclear how sound is perceived: as particle motion or sound pressure. Snapping shrimp are amongst the loudest and most pervasive marine sound sources. They produce snaps during interactions with conspecifics, and they also interact with soniferous heterospecifics. If they can hear, then sound could facilitate key behavioral interactions. We measured the auditory sensitivity of the snapping shrimp, Alpheus richardsoni, using auditory evoked potentials in response to a shaker table that generated only particle motion and an underwater speaker that generated both particle motion and sound pressure. Auditory detection was most sensitive between 80 and 100 Hz, and auditory evoked potentials were detected up to 1500 Hz. Snapping shrimp responded to both the shaker table and the underwater speaker, demonstrating that they detect acoustic particle motion. Crushing the statocyst reduced or eliminated hearing sensitivity. We conclude that snapping shrimp detect acoustic particle motion using the statocyst, they might detect conspecifics and heterospecifics, and hearing could facilitate key behavioral interactions., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Decapod crustaceans show variable degrees of euryhalinity and osmoregulatory capacity, by responding to salinity changes through anisosmotic extracellular regulation and/or cell volume regulation. Cell volume regulatory mechanisms involve exchange of inorganic ions between extra- and intra-cellular (tissue) compartments. Here, this interplay of inorganic ions between both compartments has been evaluated in four decapod species with distinct habitats and osmoregulatory strategies. The marine/estuarine species Litopenaeus vannamei (Lv) and Callinectes danae (Cd) were submitted to reduced salinity (15‰), after acclimation to 25 and 30‰, respectively. The freshwater Macrobrachium acanthurus (Ma) and Aegla schmitti (As) were submitted to increased salinity (25‰). The four species were salinity-challenged for both 5 and 10 days. Hemolymph osmolality, sodium, chloride, potassium, and magnesium were assayed. The same inorganic ions were quantified in muscle samples. Muscle hydration (MH) and ninhydrin-positive substances (NPS) were also determined. Lv showed slight hemolymph dilution, increased MH and no osmotically-relevant decreases in muscle osmolytes; Cd displayed hemolymph dilution, decreased muscular NaCl and stable MH; Ma showed hypo-regulation and steady MH, with no change in muscle ions; As conformed hemolymph sodium but hypo-regulated chloride, had stable MH and increased muscle NPS and ion levels. Hemolymph and muscle ions (especially chloride) of As were highly correlated (Pearson, +0.83). Significant exchanges between hemolymph and muscle ionic pools were more evident in the two species with comparatively less AER regulatory power, C. danae and A. schmitti. Our findings endorse that the interplay between extracellular and tissue ionic pools is especially detectable in euryhaline species with relatively lower osmoregulatory strength., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Cell line development from shrimp is not a novel venture as researchers across the globe have been trying to have crustacean cell lines over 30 years. The reason for not attaining a crustacean or precisely a shrimp cell line is believed to be the replicative senescence and the inability to maintain telomere length in vitro. Moreover, spontaneous in vitro transformations do not happen in shrimp cells. Oncogenic induction in primary cell culture is one of the ways to attain in vitro transformation by way of disrupting the mechanisms which involve cellular senescence. In this context, a recombinant baculovirus with shrimp viral promoter IHHNV-P2 was used for the transduction aimed at immortalization. An oncogene, H-ras, was successfully amplified and cloned in to the baculoviral vector, downstream to shrimp viral promoter IHHNV-P2 and upstream to GFP. Recombinant baculovirus with H-ras was generated and used for transduction into shrimp lymphoid cells during early dividing stage. Accordingly, fibroblast-like primary cell culture got developed, and H-ras and GFP expression could be confirmed. The study suggests that the simple method of incubating recombinant baculovirus with minced tissue enables in vitro transduction during early dividing stage of the cells, and the transduction efficiency gets enhanced by adding 5 mM sodium butyrate to the culture medium., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

High mortality is a frequent occurrence during live transport of shrimp species and the biochemical mechanism remains unknown. This study aimed to explore the influence of combined stress of acute cold exposure (AC) and waterless duration (WD) on survivability and biochemical response of shrimp L. vannamei during live transport. The shrimps in NC and AC groups remained the total survivability throughout the experiment while the shrimps exposed to AC + WD stress exhibited significantly higher mortality since 6h afterwards (P < 0.05) and the median survival time was calculated at 10.46 h. Moreover, the typical combined stress points at AC + WD3h, AC + WD6h and AC + WD9h were assigned for exploring the immunological and antioxidative responses. For immunity response, the total hemocyte counts (THC) decreased with the prolongation of duration time and the activities of non-specific immunity enzymes such as phenol oxidase (PO), acid phosphatase (ACP), alkaline phosphatase (AKP), aspartate aminotransferase (AST) and alanine transaminase (ALT) were significantly elevated in AC + WD9h groups (P < 0.05). Moreover, compared with that in NC group, the significant accumulation of reactive oxygen species (ROS) was observed in AC group and then reduced in combined stress groups (P < 0.05), with the highest level of malonaldehyde (MDA) in AC and AC + WD3h groups. Overall, the significant elevation of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) was detected in AC + WD9h group (P < 0.05). Furthermore, the accumulative pathological impairment on hepatopancreas tissue revealed the cytoskeleton degradation. In addition, correlation analyses visualized the correlation between oxidative stress and biochemical response. This study not only deepens our understanding on the biochemical mechanism of shrimp mortality induced by combined stress, but also provides a potential strategy for improving the management of L. vannamei during live transport., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Water temperature is one of the most common physiological stressors in aquaculture. Previous studies demonstrate that organisms require miRNA activity for survival in various unfavourable environmental conditions. However, the detailed role of miRNA in response to low-temperature stress is still unclear. This study was conducted to construct a comprehensive miRNA dataset for the Penaeus vannamei after low-temperature stress. A total of 329 known miRNAs and 60 putative novel miRNAs were identified. Among them, 17 miRNAs were identified with the most significant differences, and they were found to be involved in stimulation or stress processes. The main enriched target pathways of the 17 miRNAs were the Hippo signalling pathway, autophagy, apoptosis and MAPK signalling. In addition, all the 17 miRNAs identified were up-regulated, suggesting that miRNA by inhibiting the expression of target genes constitutes an effective strategy for Penaeus vannamei to cope with low-temperature stress. The 35-putative target of the 17 miRNAs was related to apoptosis and autophagy-related proteins, such as Pxt, DRAM2, cytochrome c, ATG2B, JNK, ATG4 and API5. The analysis of miRNA expression profiles contributes to the understanding of the molecular mechanisms of low-temperature tolerance in Penaeus vannamei. This study's findings enrich current miRNA resources and offer the possibility to validate the involvement of 17 miRNAs in the response of shrimp to low-temperature stress., (© 2021 John Wiley & Sons Ltd.)

Male sex differentiation in the crustacean is best known to be controlled by the insulin-like androgenic gland hormone (IAG). In this report, the cDNA and gene of the shrimp Fenneropenaeus merguiensis FmIAG were studied and characterized. FmIAG gene shares a high sequence identity in the coding region as well as the promoter region with that of F. chinensis. FmIAG gene is most likely consists of 5 exons and 4 introns. The cDNA reported here is the most abundant transcript that retained cryptic intron 4. The use of different splicing acceptor sites in exon 2 can produce a long-form FmIAG transcript variant with 6 additional amino acids inserted. Splicing of cryptic intron 4 would produce a transcript variant with a different C-terminal end. Therefore 4 different FmIAG transcripts can be produced from the FmIAG gene. During the molt cycle, the expression level of FmIAG was low in the early intermolt, increase steadily towards the late premolt and decreased rapidly in the early postmolt. In addition to the androgenic gland, FmIAG is also expressed in the hepatopancreas and ovary of adult females. Unilateral eyestalk ablation caused a significant increase in FmIAG transcript suggesting that the eyestalk consists of inhibiting factor(s) that suppressesFmIAGexpression. To explore the function of FmIAG in males, injection of FmIAG dsRNA knock-down the expression of FmIAG and up-regulated the expression of the vitellogenin gene in the testis and hepatopancreas. Interestingly a CHH-like gene identified in the androgenic gland was down-regulated. CHH-like gene knock-down resulted in altered expression of FmIAG in males suggesting that the CHH-like may be involved in FmIAG's regulation. RT-PCR with specific primers to the different transcript variant were used to determine if there is an association of different sizes of male and the type of IAG transcript. Results indicated that a high percentage of the large male shrimp expressed the long-form of FmIAG. The results suggested that FmIAG may be useful as a size marker for male shrimp aquaculture. In summary, the results of this study have expanded our knowledge of shrimp insulin-like androgenic gland hormone in male sex development and its potential role as a marker gene for growth regulation in shrimp., (Copyright © 2021. Published by Elsevier B.V.)

The aim of this study was to evaluate egg production and quality of females of the Pacific white shrimp, Litopenaeus vannamei, in which there was or was not unilateral eyestalk ablation after there was pre-maturation culturing in biofloc or clear-water systems. Acylglycerides, cholesterol, glucose and total soluble protein were determined for the hepatopancreas, ovaries, hemolymph and eggs. Females cultured using the biofloc system had a larger number of eggs released per spawning and per gram of spawning specimen body weight. The number of total spawning's per week was comparable among treatments. Females cultured in the biofloc system in which there was no eyestalk ablation had that greatest concentrations of nutrient reserves in the hepatopancreas (P < 0.05) with the females cultured in the biofloc and clear-water system that had eye stalk ablation having the next most abundant nutrient reserves. There were the least concentrations of nutrient reserves in females with eyestalk ablation cultured in the clear-water system (P < 0.05). There, however, were no difference in nutrient reserve concentrations in the hemolymph and ovaries. In the eggs, there was the same trend among treatments as the hepatopancreas nutrient reserves, indicating that both eyestalk ablation and pre-maturation culture conditions (i.e., either biofloc or clear-water) affected the quality of eggs in L. vannamei., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Heat-killed Vibrio alginolyticus (HVa), formalin-inactivated V. alginolyticus (FVa), heat-killed Vibrio harveyi (HVh), formalin-inactivated V. harveyi (FVh), live V. alginolyticus (LVa), and live V. harveyi (LVh) were used in this study. White shrimp Litopenaeus vannamei receiving two mixtures (HVa + FVa) or four mixtures (HVa + FVa + HVh + FVh) served as primary exposure, and shrimp receiving LVa or LVh afterward served as secondary exposure. Shrimp receiving marine saline and then receiving either LVa or LVh served as controls. Phagocytic activity and clearance efficiency were examined in shrimp that received two mixtures after 1-8 weeks and then received LVa. Both the phagocytic activity and clearance efficiency of shrimp receiving two mixtures were significantly higher than in control shrimp after 1-8 weeks. In another experiment, phagocytic activity and clearance efficiency were examined in shrimp that received four mixtures after 1-8 weeks and then received LVa and LVh, respectively. The phagocytic activity of shrimp receiving four mixtures was significantly higher than in control shrimp after 1-8 weeks post exposure to LVa and LVh. The clearance efficiency of shrimp receiving four mixtures was significantly higher than in control shrimp after 1-6 weeks post exposure to LVa, and 1-7 weeks post exposure to LVh. In the other experiment, the survival rate of shrimp that received four mixtures after five weeks were challenged with LVa at 6.4 × 10 7  colony-forming units (cfu) shrimp -1 and LVh at 4.4 × 10 6  cfu shrimp -1 . Shrimp that received marine saline for five weeks and then challenged with LVa and LVh at a same dose served as challenged controls. The survival rate of shrimp that received four mixtures was significantly higher (90%) than that of control shrimp (67%), and significantly higher (73%) than that of control shrimp (53%) after 3-7 days post challenge with LVa and LVh. It is concluded that the mixtures have feature of adjuvant and antigen, and shrimp receiving mixtures of heat-killed and formalin-inactivated V. alginolyticus and V. harveyi even after 5-8 weeks exhibit memory recall and show increased phagocytosis and resistance to Vibrio infections., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The present study aims to investigate the effects of dietary synbiotics supplementation methods on growth, feed utilization, hepatopancreas and intestinal histology, non-specific immunity and microbiota community of Pacific white shrimp (Litopenaeus vannamei). A control diet was designed to contain 18% fish meal (CON), and then 3 g kg -1 synbiotics (Bioture, consisting of Bacillus subtilis, Saccharomyces cerevisiae, β-glucan and mannan oligosaccharide, etc) was supplemented to the control diet with three methods, directly adding in diets for pelleting (DAP), spraying diets after pelleting at once (SDA), spraying diets before feeding every day (SDE). Shrimp with initial body weight of 1.5 ± 0.12 g were fed one of the four diets for 56 days. The results showed that dietary synbiotics significantly increased the weight gain (WG), apparent digestibility coefficient (ADC) of crude protein (CP) and dry matter (DM), hepatopancreatic protease activity and decreased feed conversion ratio (FCR) (P < 0.05). Among the three synbiotics-added diets, SDE group showed the best growth with significantly higher WG than DAP group (P < 0.05). Serum activities of total superoxide dismutase, catalase, acid phosphatase, lysozyme and alkaline phosphatase of synbiotics-added groups were significantly higher, and serum malondialdehyde level was significantly lower than those of the control (P < 0.05). The intestinal villus width and villus number were also increased by the supplementation of synbiotics. The cumulative mortality was reduced in the three synbiotics-added groups after challenging with Vibrio parahaemolyticus (P < 0.05), and SDE group showed a significantly lower mortality than the control and DAP groups (P < 0.05). In intestinal microbiota composition, the abundance of Lactococcus tended to increase and Vibro tended to decreased in SDA and SDE groups. In conclusion, dietary synbiotics improved the growth, feed utilization, intestine health and non-specific immunity of Pacific white shrimp, and spraying synbiotics on diet presented better performance than adding synbiotics in diet for pelleting., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Low oxygen concentration in water (hypoxia) and high temperature are becoming more frequent due to climate change, forcing animals to endure stress or decease. Hypoxia and high temperature stress can lead to reactive oxygen species (ROS) accumulation and oxidative damage to the organisms. The shrimp Litopenaeus vannamei is the most cultivated crustacean worldwide. The aim of this study was to evaluate the expression and enzymatic activity of glutathione peroxidase (GPx), catalase (CAT) and cytosolic manganese superoxide dismutase (cMnSOD) in gills and hepatopancreas from L. vannamei in response to two combined stressors: hypoxia and reoxygenation at control and high temperature (28 vs 35 °C, respectively). In addition, glutathione and hydrogen peroxide content were analyzed. The changes were mainly tissue-specific. In gills, cMnSOD expression and enzymatic activity increased in response to the interactions between oxygen variation and thermal stress, while GPx and CAT were maintained. More changes occurred in GPx, CAT and MnSOD in hepatopancreas than in gills, mainly due to the effect of the individual stress factors of thermal stress or oxygen variations. On the other hand, the redox state of glutathione indicated that during high temperature, changes in the GSH/GSSG ratio occurred due to the fluctuations of GSSG. Hydrogen peroxide concentration was not affected by thermal stress or oxygen variations in hepatopancreas, whereas in gills, it was not detected. Altogether, these results indicate a complex pattern of antioxidant response to hypoxia, reoxygenation, high temperature and their combinations., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Global climate change induced warming has profound repercussion on physiological performances of marine animals. The Indian Sundarban is one of the best nursery grounds for various shrimp populations which need estuarine realm to complete their bipartite life cycle. From last couple of decades, a clear indication of temperature escalation has been identified in Sundarban. In the present study, we have assessed the physiological energetics of Penaeus monodon post larvae from Indian Sundarban under different temperatures, 28 °C (annual average habitat temperature) and elevated temperatures 30 °C, 32 °C, 34 °C in a month long mesocosm experiment. Significant alterations were observed in growth performances as well as physiological energetics. The length, weight, survival percentages, ingestion rates were reduced, howbeit respiration and ammonia excretion rate had been increased in elevated temperature treatments culminating in a negative Scope for Growth. PERMANOVA results showed a significant (p ≤ 0.05) variation in different physiological performances of shrimp post larvae both in different temperature treatments and days of exposure. The present results clearly highlighted the detrimental effect of elevated temperature on physiological energetics of shrimp larvae that might potentially reduce shrimp population and affect the coastal fishery., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study was aimed to evaluate the efficiency of Sargassum polycystum and nucleotides- supplemented diets to improve immune response and cold-tolerance of juvenile Litopenaeus vannamei . Four treatments were evaluated: T1, the control, shrimp received only a basal diet; T2, a basal diet with 500 ppm nucleotides; T3, a basal diet with 500 ppm S. polycystum powdered; T4, a basal diet with 500 ppm nucleotides and 500 ppm S. polycystum powdered. Shrimp were fed experimental diets for 56 days. Results revealed shrimp fed T4 diet exhibited the best significant improvement in water quality, survival, growth, and feed utilization indices followed by T2, and T3, while T1 showed the worst values. Additionally, nonspecific immune responses (phagocytosis (%), lysozyme, phenoloxidase, super oxide dismutase (SOD) activity, total nitric oxide) were improved with 1.7-3.2-fold in T4 higher than T1. Histomorphology of hepatopancreas in T4 showed the most increased activation of the hepatic glandular duct system compared with the other treatments. Moreover, nucleotides/seaweed-supplemented diets upregulated relative expression of cMnSOD , Penaeidin4 , and heat shock protein70 ( HSP70 ) genes, while translationally controlled tumor protein (TCTP) was downregulated. In conclusion, the synergistic effects of both S. polycystum and nucleotides have many advantages as a growth promoter, immunostimulant, antimicrobial, and cold-tolerant stimulant to L. vannamei .

Marine feed ingredients derived from cephalopods (e.g., squid) and crustaceans (e.g., krill) are commercially used to improve the palatability of shrimp diets. Increase in global demand for shrimps has resulted in overfishing of these marine organisms and is a matter of concern. Insect protein hydrolysate could be a sustainable alternative for the possible replacement of these marine feed ingredients. During this study, four formulations: diet A (control: not containing any palatability enhancer), diet B (containing squid meal and krill oil), diet C (containing 1% insect protein hydrolysate), and diet D (containing 2% insect protein hydrolysate) were tested for (1) time required by first subject to begin feeding (time to strike) and (2) palatability in Litopenaeus vannamei . Additionally, the chemical composition of all four diet formulations was also analyzed. Results indicate that all diets had similar crude composition. The major essential amino acids in all diets were leucine and lysine, whereas eicosapentaenoic acid was the major omega-3 fatty acid in all diets. There were no significant differences between the mean time to strike for all the tested formulations. Palatability of tested formulations was found in the following order: diet D > diet C > diet B = diet A ( p < 0.05), indicating that addition of squid meal and krill oil has no effect on palatability in comparison to control, whereas inclusion of insect protein hydrolysates significantly improves the palatability of formulations. Palatability enhancement potential of insect protein hydrolysate could be attributed to the high free amino acid content and water solubility in comparison to squid meal.

Cell division cycle 37 (Cdc37) is an important cytoplasmic phosphoprotein, which usually functions as a complex with heat shock protein 90 (Hsp90), to effectively reduce the damage caused by heavy metals, such as cadmium (Cd), in aquatic animals. The high toxicity of Cd in aquatic systems generally has a deleterious effect on healthy farming of shrimps. In the present study, a novel Cdc37 gene from Penaeus monodon was identified and designated as PmCdc37. Following exposure to Cd stress, the expression levels of PmCdc37 were upregulated at the transcriptional level in both the hepatopancreas and hemolymph. RNA interference and recombinant protein injection experiments were carried out to determine the function of PmCdc37 in P. monodon following Cd exposure. To clarify the correlations between PmCdc37 and PmHsp90, the respective recombinant proteins were expressed in vitro, and the ATPase activity of PmHsp90, with or without PmCdc37, was assessed. Moreover, a pull-down assay was conducted to detect the correlation between PmCdc37 and PmHsp90. After analyzing the expression patterns of PmHsp90 following Cd challenge, whether PmHsp90 can promote the ability of PmCdc37 to resist Cd stress or not was investigated. The results showed that formation of a PmHsp90/PmCdc37 complex protected shrimp against Cd stress-induced damage. Moreover, we also confirmed that PmSOD is involved in Cd stress, and that the PmHsp90/PmCdc37 complex can regulate SOD enzymatic activity. PmSOD was involved in decreasing the MDA content in shrimp hemolymph caused by Cd stress. We concluded that during exposure to Cd, the PmHsp90/PmCdc37 complex increases SOD enzyme activity, and in turn decreases the MDA content, thereby protecting shrimp against the damage caused by Cd stress. The present studies contribute to understanding the molecular mechanism underlying resistance to Cd stress in shrimp., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Litopenaeus vannamei (L. vannamei) is one of the most widely cultured shrimp species in the world. The species often suffers from cold stress. To understand the molecular mechanism of cold tolerance, we performed transcriptomic analysis on two contrasting cultivars of L. vannamei, namely, cold-tolerant Guihai 2 (GH2) and cold-sensitive Guihai1 (GH1), under a control temperature (28 °C), cold stress (16 °C), and recovery to 28 °C. A total of 84.5 Gb of sequences were generated from 12 L. vannamei hepatopancreas libraries. The de-novo assembly generated a total of 143,029 unigenes with a mean size of 1,052 bp and an N50 of 2,604 bp, of which 34.08% were annotated in the Nr database. We analyzed the differentially expressed genes (DEGs) between nine comparison groups and detected a total of 21,026 DEGs. KEGG pathways, including lysosome, sphingolipid metabolism and nitrogen metabolism, were significantly enriched by DEGs between different temperatures in GH2. Furthermore, eight of the most significantly DEGs under cold stress from the transcriptomic analysis were selected for quantitative real-time PCR (qPCR) validation. Overall, we compared gene expression changes under cold stress in cold-tolerant and cold-sensitive L. vannamei for the first time. The results may further extend our understanding of the cold stress-response mechanism in L. vannamei., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Argonaute family is phylogenetically subdivided into Ago and Piwi subfamilies that operate either transcriptional or post-transcriptional regulation in association with particular types of small RNAs. Among the four members of Ago subfamily (PmAgo1-4) found in black tiger shrimp Penaeus monodon, PmAgo4 exhibits gonad-restricted expression and takes part in transposon repression as the Piwi subfamily. While PmAgo1-3 participate in RNA interference (RNAi)-based mechanism, the role of PmAgo4 in RNAi is still mysterious, and was therefore investigated in this study. The results showed that knockdown of PmAgo4 in shrimp testis did not have a significant effect on the potency of PmRab7 silencing by dsPmRab7. In addition, replication of YHV as well as YHV-induced cumulative mortality in PmAgo4-knockdown shrimp are comparable to the control shrimp, suggesting the irrelevant association of PmAgo4 with RNAi-mediated gene silencing and antiviral immunity. Since PmAgo4 did not function in common with the Ago subfamily, its potential function in gametogenesis of male shrimp was further investigated. The reduction of PmAgo4 transcript levels in male shrimp revealed significant defect in testicular maturity as measured by Testicular Index (TI). Moreover, the numbers of mature sperm in spermatophore of PmAgo4-knockdown shrimp were significantly decreased comparing with the control shrimp. Our studies thus suggest a distinctive role of PmAgo4 that is not consistent with a dsRNA-mediate gene regulation and virus replication, but has a key function in controlling spermatogenesis in P. monodon., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

With the worldwide demand for tropical penaeid prawn increasing in recent decades, more research on shrimp culture methods is needed to enhance efficiency and profitability for shrimp farmers. The objective of this study was to develop a technique to boost the productivity, feed efficiency, and profitability of the giant tiger prawn (Penaeus monodon). To accomplish this, a novel culture setup was established in which two benthic organisms, a filamentous green alga (Chaetomorpha sp.) and a microsnail (Stenothyra sp.), were propagated together with P. monodon post-larvae during an early culture stage and then offered to shrimp as supplementary live feeds in intensive aquaculture ponds. For the experiment, shrimp post-larvae (density: approximately 33 individuals m-2) were cultured in outdoor concrete ponds (9 × 9 × 1.2 m) under either control (fed only artificial feed, n = 3) or experimental (fed artificial feed and benthic organisms, n = 3) conditions until they reached marketable size (15 weeks). Apparent green algae consumption was 6.81 kg (8.4% green alga to total feed consumption), whereas microsnail consumption was 1.96 kg (2.4% microsnail to total feed consumption). Compared with the control group of giant tiger prawn, the experimental group showed significantly higher productivity (total number of shrimp produced: 118%; total shrimp production: 133%), feed efficiency (feed conversion ratio of artificial shrimp feed: 89%), and profitability (shrimp sales: 139%; balance between shrimp sales and costs: 146%), while labor and financial costs were kept minimal. These results can be explained by the enhanced growth of shrimp at the early stages of culture. The techniques developed in this study will help to advance the efficiency of intensive aquaculture operations for giant tiger prawn and also improve profitability for shrimp farmers., Competing Interests: The authors have declared that no competing interests exist.

The elevated NH 3 -N and NO 2 -N pollution problems in mariculture have raised concerns because they pose threats to animal health and coastal and offshore environments. Supplement of Marichromatium gracile YL28 (YL28) into polluted shrimp rearing water and sediment significantly decreased ammonia and nitrite concentrations, showing that YL28 functioned as a novel safe marine probiotic in the shrimp culture industry. The diversity of aquatic bacteria in the shrimp mariculture ecosystems was studied by sequencing the V4 region of 16S rRNA genes, with respect to additions of YL28 at the low and high concentrations. It was revealed by 16S rRNA sequencing analysis that Proteobacteria, Planctomycete and Bacteroidetes dominated the community (>80% of operational taxonomic units (OTUs)). Up to 41.6% of the predominant bacterial members were placed in the classes Gammaproteobacteria (14%), Deltaproteobacteria (14%), Planctomycetacia (8%) and Alphaproteobacteria (5.6%) while 40% of OTUs belonged to unclassified ones or others, indicating that the considerable bacterial populations were novel in our shrimp mariculture. Bacterial communities were similar between YL28 supplements and control groups (without addition of YL28) revealed by the β-diversity using PCoA, demonstrating that the additions of YL28 did not disturb the microbiota in shrimp mariculture ecosystems. Instead, the addition of YL28 increased the relative abundance of ammonia-oxidizing and denitrifying bacteria. The quantitative PCR analysis further showed that key genes including nifH and amoA involved in nitrification and nitrate or nitrite reduction significantly increased with YL28 supplementation ( p < 0.05). The supplement of YL28 decreased the relative abundance of potential pathogen Vibrio . Together, our studies showed that supplement of YL28 improved the water quality by increasing the relative abundance of ammonia-oxidizing and denitrifying bacteria while the microbial community structure persisted in shrimp mariculture ecosystems.

In aquatic ecosystems, the temperature of the water is an important ecological factor that modulates aquatic organisms' metabolism, growth, development, and reproduction. In this study, the morphological, transcriptomic, and metabolomic analyses of response of Marsupeneus japonicus to acute cold stress was investigated. The results revealed that low temperature caused profound morphological damage to the hepatopancreas. Transcriptomic responses suggested that energy and primary metabolism, cytoskeleton structure, and apoptosis signaling were altered. The metabolic responses to cold stress included changes of multiple amino acids and unsaturated fatty acids. Combined transcriptomic and metabolomic data indicated that energy metabolism pathways were downregulated in the hepatopancreas under cold stress. However, M. japonicus increased ATP and unsaturated fatty acids production to ameliorate. Moreover, cold stress caused significant attenuation of macrophage apoptosis. This study provides key information to increase our understanding of low-temperature tolerance in shrimp., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Diazinon is one of the insecticides that represent a high risk for Costa Rican estuarine environments due to its widespread use in pineapple plantations. In estuaries, organisms are frequently submitted to stress caused by natural factors (e.g., continuous changes in salinity levels) and, additionally, to stress due to contamination. Therefore, the driving question of this study was: will organisms be more susceptible to suffer the deleterious effects caused by diazinon because of the stress resulting from the salinity changes? The estuarine shrimp Penaeus vannamei was used as the model organism and two responses were measured: osmoregulation (the physiological effect after a forced and continuous 24 h-exposure) and avoidance [the behavioural effect after a short (3 h) non-forced, multi-compartmented exposure]. Juveniles were exposed to diazinon (0.1, 1, 10 and 100 μg/L) at three different salinities (10, 20 and 30). Disruption in the capacity to regulate the haemolymph osmotic pressure was observed at a salinity of 30 in individuals exposed to diazinon and methanol (used as vehicle). At that salinity, the ability of shrimps to detect and avoid the highest diazinon concentrations was impaired. P. vannamei juveniles inhabit environments with a high variation in salinity, but with an optimum osmotic point close to a salinity of 20; therefore, the higher the salinity, the greater the vulnerability of shrimps to the effects of diazinon. From an ecological point of view, this combined effect of salinity and contamination might also limit the spatial distribution of the organisms., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Expression levels of hemocyanin (LvHc), activating transcription factor 4 (LvAtf4), glutathione S-transferase (LvGst), caspase 2 (LvCasp2) and anti-lipopolysaccharide factor (LvAlf) were examined in the hepatopancreas of Pacific white shrimp Litopenaeus vannamei juveniles exposed to a lethal concentration of ammonia-N (32.15 mg/l). The expression levels of all transcripts except LvAlf were significantly greater (P < 0.05) in tolerant shrimp (Lv-AT; N = 30) that survived up to 72 h post treatment (hpt) than in susceptible shrimp (Lv-AS24 and Lv-AS72; N = 45 and 15), that died within 24 h or between 24 and 72 hpt, respectively. Subsequently, effects of non-lethal concentrations of ammonia-N (control, 10 and 20 mg/l) on the expression of LvHc in juvenile shrimp were examined. Compared to the control, expression levels of LvHc transcripts in hemocytes and the hepatopancreas of tested shrimp changed after exposure to ammonia-N. One SNP (C > T 545 ) was found in the LvHc 322 gene segment. Real-time PCR amplification of specific alleles (real-time PASA) was developed for detection of C > T 545 genotypes. Juveniles in the lethal exposure test that carried a C/T 545 genotype showed a greater average body weight and total length (8.46 ± 0.36 g and 10.05 ± 0.16 cm) than those with a C/C 545 genotype (7.48 ± 0.31 g and 9.60 ± 0.13 cm) (P < 0.05). Similar results were found in the second generation (G2) of a growth-improved stock (3 and 4 families of BIOTEC-G2-L1 and BIOTEC-G2-L2) and in commercially farmed shrimp (2 groups). Accordingly, expression levels and SNP of LvHc can serve as markers for selection high growth performance in ammonia-tolerant L. vannamei., (Copyright © 2020 Elsevier Ltd. All rights reserved.)