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The present study was designed to investigate the effects of supplementation with freeze-dried Clostridium butyricum (CB) powder on the growth, immune function and intestinal health of Litopenaeus vannamei after replacing fishmeal in the diet with cottonseed protein concentrate (CPC). Six treatment groups were designed, namely the control group (CON, 25% fish meal) and five alternative groups (CPC replacing 40% fishmeal protein in the control group). Based on the alternative group, 0%, 0.065%, 0.26%, 1.04%, and 4.16% of freeze-dried CB bacterial powder (4.6 × 108 CFU/g) were added, recorded as CB 0, CB 0.065, CB 0.26, CB 1.04, and CB 4.16, respectively. Each treatment had 3 replicates of 40 shrimps (0.29 ± 0.01 g) each and breeding for 8 weeks. After the experiment, serum enzyme activities, muscle amino acids, and intestinal parameters (short-chain fatty acids, digestive enzymes, gene expression, and microbiota) were tested to explore the effects of freeze-dried CB powder in shrimp aquaculture. The results showed that the CB1.04 group had the highest final body weight, weight gain rate, and specific growth ratio (P > 0.05). Freeze-dried CB powder increased the activity of serum superoxide dismutase, glutathione peroxidase, complement 3, and complement 4. Muscle tyrosine, proline, and total essential amino acids were remarkably increased in the CB 1.04 group (P < 0.05). Propionic acid levels were elevated in the CB 1.04 and CB4.16 groups (P < 0.001). The relative expression of Dorsal, Relish, and Target of Rapamycin (TOR) genes was significantly increased in the CB 1.04 group (P < 0.01). Actinobacteria and Demequina abundance was significantly higher in the CB 1.04 group (P < 0.01). The results of the Vibrio parahaemolyticus challenge test showed the highest cumulative mortality rate (43.33%) in the CB0 group and the lowest cumulative mortality rate (20%) in the CB1.04 group. This study confirmed that freeze-dried CB powder alleviated the negative effects of CPC replacement of fish meal protein in Litopenaeus vannamei, and the optimum additive level was 2.11% (9.71 × 109 CFU/kg) as indicated by binary regression analysis of specific growth ratio. [ABSTRACT FROM AUTHOR]

The research investigated the nutritional physiology effect of ginseng saponins on Litopenaeus vannamei (L. vannamei) under low-fishmeal diets. In total, five experimental groups were arranged, with 21% fishmeal (high-fishmeal) serving as the positive control (PC), 11% fishmeal (low-fishmeal) serving as the negative control (NC), and 11% fishmeal serving as the addition in all three other groups. Similarly, ginseng saponins (GSP, purity of 2%) were added in the order of 0.1%, 0.3%, and 0.5% (GSP0.1, GSP0.3, and GSP0.5), with an 8-week growth cycle. Both GSP0.1 and GSP0.3 showed significantly higher growth performance (final body weight, FBW; weight gain rate, WGR; specific growth rate, SGR) than the NC group, but significantly lower growth performance than the PC group (P <0.05). However, it was found that there was no significant difference in the body composition of the whole shrimp between the experimental groups. Compared to the PC group, the GSP0.3 group exhibited significantly elevated levels of antioxidant enzymes, total antioxidant capacities (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) (P <0.05). Additionally, significant differences were observed between the PC and GSP0.3 groups regarding the expression levels of sod , cat , and gsh-px (P<0.05). And there was a better morphological organization of shrimp hepatopancreas in the GSP0.3 group than in all other groups. In comparison with the PC group, there was no significant difference in shrimp survival rates after ammonia nitrogen stress with ginseng saponins added (P >0.05). Whereas, in terms of the relative expression levels of the corresponding genes, in shrimp of the GSP0.3 group, the relative expression of antioxidant-related genes sod , cat , and gsh-px were significantly higher than that of the PC group (P <0.05). Caspase3 and p53 , along with bcl-2 and bax , were found to be significantly more expressed in shrimp of the GSP0.3 group than in all other groups (P <0.05). These findings imply that in addition to improving growth performance, adding ginseng saponins at a concentration of 11% fishmeal could improve the antioxidant capacity of L. vannamei as well as its resistance to stress. Therefore, ginseng saponins can be utilized as a functional additive to increase L. vannamei growth performance, enhance antioxidant capacity, and reduce stress in low-fishmeal diets, 0.3% of ginseng saponins is optimal. [ABSTRACT FROM AUTHOR]

The problem with superintensive vannamei shrimp cultivation is the increase in N and P concentrations which can cause eutrophication and blooming algae. Therefore, this research aims to obtain data and information regarding plankton dynamics and water quality in super intensive vannamei shrimp cultivation at different densities. The research used 3 pond plots with a shrimp density of 750 individuals/m2 (A); 1,000 heads/m²; and 1,250 heads/m2. Plankton data was collected through observation by filtering pond water at five points using planktonnet no. 25, 20 liters at 5 sampling points or 100 liters of water per plot, and sampling was carried out every 7 days. The results of statistical analysis show spearman correlation analysis showed that shrimp density did not have a significant effect on plankton abundance, phytoplankton abundance, zooplankton abundance, TAN, NO2, NO3, PO4, and TSS because the sig value. 2-tailed P > 0.05. however, the abundance of phytoplankton had a significant influence on the abundance of zooplankton (P < 0.05). while zooplankton abundance was influenced by NO2 (P < 0.05). The close relationship between shrimp density and the abundance of plankton, phytoplankton, zooplankton, and water quality (TAN, NO2, NO3, PO4, and TSS) is very low (-0.85-2.79). positive and very close correlation between plankton density, phytoplankton density and zooplankton density (0.68-0.956), and negative correlation with water quality (TAN, NO2, NO3, PO4, and TSS). This causes the distribution of low levels of diversity (H) and evenness (E), so that the average dominance index is below 1, which indicates the absence of dominant individuals. Therefore, in the three treatments no dangerous plankton blooming was found. [ABSTRACT FROM AUTHOR]

Our work evaluated the possible underlying roles of dietary dried seaweed (Gracilaria verrucosa; GV) on the inherent immune response, antioxidant capacity, immune-related gene expression, and protection of whiteleg shrimp (Litopenaeus vannamei) contra white spot syndrome virus (WSSV). Three hundred and sixty healthy L. vannamei (15.26 g ± 1.29 g) were graded into four supplemental groups (Triplicate/group) and fed with diets including 0 (control), 2, 4, and 8 g GV (kg diet) −1 for 21 days. Following the feeding period, each group of shrimp received an intramuscular WSSV injection (1.4 × 106 copies/ml). Hemolymph and gills samples were collected before and after the challenge with WSSV. Notably, the administration of dietary GV significantly enhanced the innate immune parameters of pacific white shrimp including total hemocyte count (THC), phagocytosis, phenoloxidase activity, reactive oxygen species (ROS) production, and lysozyme activity before and after challenge with WSSV. Additionally, dietary supplementation of 4, and 8 g of GV (kg diet)−1 remarkably elevated ACP, AKP, SOD, GPx, and catalase activities along with a decrease in the MDA level in gills of shrimp before and post-WSSV challenge. In response to the GV supplement, significant upregulation of expression of ALF1, CRU1, PEN4, and CTL with downregulation of TRAF6, STAT, TLR1, and NOS genes was recorded in the gills tissue before and post-challenge with WSSV, especially at a dose of 8.0 GV g kg − 1. Dietary inoculated shrimp with GV revealed notably higher survival percentages after being challenged with WSSV. Conclusively, these data indicate that Gracilaria verrucosa can be recommended as a valuable supplemented seaweed to stimulate the innate immunity and enhance the health of Litopenaeus vannamei against viral infection. [ABSTRACT FROM AUTHOR]

The insulin receptor (IR) plays a crucial role in the growth and metabolism of animals. However, there are still many questions regarding the IR in crustaceans, particularly their role in shrimp growth and glucose metabolism. In this study, we identified a novel insulin-like receptor gene in Litopenaeus vannamei and cloned its full length of 6439 bp. This gene exhibited a highly conserved sequence and structural characteristics. Phylogenetic analysis confirmed it as an unreported RTK2-type IR, namely, LvRTK2. Expression pattern analysis showed that LvRTK2 is primarily expressed in female reproductive and digestive organs. Through a series of in vivo and in vitro experiments, including glucose treatment, exogenous insulin treatment, and starvation treatment, LvRTK2 was confirmed to be involved in the endogenous glucose metabolic pathway of shrimp under different glucose variations. Moreover, long-term and short-term interference experiments with LvRTK2 revealed that the interference significantly reduced the shrimp growth rate and serum glucose clearance rate. Further studies indicated that LvRTK2 may regulate shrimp growth by modulating the downstream PI3K/AKT signaling pathway and a series of glucose metabolism events, such as glycolysis, gluconeogenesis, glycogen synthesis, and glycogenolysis. This report on the characteristics and functions of LvRTK2 confirms the important role of RTK2-type IRs in regulating shrimp growth and glucose metabolism. [ABSTRACT FROM AUTHOR]

Simple Summary: The outbreak of white spot syndrome poses a significant threat to the shrimp farming industry. To explore the interaction between Litopenaeus vannamei and the pathogenic white spot syndrome virus (WSSV), this study cloned and analyzed an important pattern recognition receptor, the C-type lectin ladderlectin (LvLL). The results revealed that LvLL in L. vannamei promoted WSSV replication, thereby affecting shrimp survival rates. This study demonstrated the role of LvLL in the resistance of L. vannamei to WSSV, providing theoretical insights into the mechanisms of shrimp resistance to the virus. C-type lectins are known for agglutination activity and play crucial roles in regulating the prophenoloxidase (proPO) activation system, enhancing phagocytosis and encapsulation, synthesizing antimicrobial peptides, and mediating antiviral immune responses. This work cloned a C-type lectin, ladderlectin (LvLL), from Litopenaeus vannamei. LvLL comprised a 531 bp open reading frame (ORF) that encoded 176 amino acids. The predicted LvLL protein included a signal peptide and a CLECT domain. LvLL was predicted to feature a transmembrane region, suggesting it may be a transmembrane protein. LvLL was predominantly expressed in the shrimp's hepatopancreas. After WSSV infection, LvLL expression in the hepatopancreas increased significantly by 11.35-fold after 228 h, indicating a general upregulation. Knockdown of LvLL resulted in a significant decrease in WSSV viral load and a notable increase in shrimp survival rates. Additionally, knockdown of LvLL led to a significant downregulation of apoptosis-related genes Bcl-2 and caspase 8 and a significant upregulation of p53 and proPO in WSSV-infected shrimp. This study showed that LvLL played a vital role in the interaction between L. vannamei and WSSV. [ABSTRACT FROM AUTHOR]

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a harmful virus that is responsible for the remarkable economic loss of Litopenaeus vannamei culture. IHHNV was first observed in shrimps, which were characterized by light microscopy, SEM, and TEM. The infected shrimps showed severe morphological deformity, including reduced body size, bent rostrum, shrunken and twisted antenna, rough cuticles, shrunken eyes, and rigid muscles. The antennal segments of the infected shrimps were fused together, puffy, dented, bent, and rough, as observed under a scanning electron microscope. The affected shrimps also showed tumor-like growth (hyperplasia) at the lateral position of the carapace in which the gastrofrontal sulcus was bent. This hyperplasia was found to be soft. In addition, the connective tissue of the diseased shrimp was in a degraded state, and the muscle fibers were despoiled. The nucleus of the cells from the infected gill cells of the shrimps was almost occupied by viral icosahedral particles, which TEM revealed. These viral particles were also found in the cytoplasm in a scattered manner within the same cells and were identified as IHHNV, as confirmed by polymerase chain reaction. [ABSTRACT FROM AUTHOR]

This study focuses on the Litopenaeus vannamei shrimp, exploring its development, dilemmas, and challenges in China's industry alongside countermeasures implemented by Chinese authorities and agencies. Since its introduction to China in 1988, L. vannamei, known for its high economic value and adaptability, has become China's leading mariculture shrimp species and one of the most significant globally. The thriving L. vannamei industry has boosted economic gains and job creation in China's marine fisheries, supplied high-quality protein to consumers, and fostered socio-economic growth. Additionally, China's experiences and lessons in the L. vannamei industry serve as valuable references for other shrimp-farming nations, promoting global industry health. Despite its success, the industry faces challenges, including germplasm resource scarcity, feed ingredient shortages, disease management, and wastewater treatment. To address these issues, China has initiated various strategies, including germplasm resource conservation, the development of low-fishmeal protein feeds, disease monitoring, and wastewater management, aiming for the industry's green and sustainable evolution. This paper asserts that China's initiatives in advancing the L. vannamei industry offer significant inspiration globally, particularly in two main areas: Firstly, through effective policy support, China has fostered research and development of new shrimp varieties suited to its aquaculture conditions, enhancing germplasm quality and breeding efficiency. Secondly, China has actively disseminated its innovations, outcomes, and experiences globally, hosting various aquaculture training sessions and seminars. These initiatives offer technical support and platforms for international dialogue, fostering cooperation and exchange among shrimp farming nations. Moreover, China's dedication to advancing artificial culture technology for L. vannamei--through collaborative and continuous research across breeding, nutrition, disease management, and sustainability--has led to significant industry advancements. These contributions not only extend the industry chain but also position China as a leader and model for global shrimp aquaculture innovation. Through this study, we aim to offer insights and practical advice by analyzing the challenges and responses within China's L. vannamei industry. We hope these findings will serve as valuable references for enhancing the global shrimp aquaculture industry and aid other nations in their aquaculture endeavors. [ABSTRACT FROM AUTHOR]

The stress level of vannamei shrimp (Litopenaeus vannamei) is affected by increased density and several genes are expressed under the condition. This study aimed to determine the expression of genes encoding white shrimp stress after density treatment and the infectious myonecrosis virus (IMNV) challenge test. A completely randomized design (CRD) was carried out with 6 treatment groups, i.e. 3 different stocking density groups without IMNV infection (100, 200, and 400 shrimp/m² ) and 3 different stocking density groups + IMNV infection (100, 200, and 400 shrimp/m² ). In addition, a shrimp density of 400 shrimp/m² reported the fastest rate of developing the IMNV virus as seen from the clinical symptoms. The lowest cumulative number of shrimp deaths was at a density of 100 shrimp/m² and was caused by the IMNV virus confirmed through RTPCR. Expression of stress-coding genes was divided into upregulated and downregulated characteristics. The upregulated genes were lectin and translationally controlled tumor protein (TCTP), while the downregulated gene was Toll Receptor. The results showed that the expression of genes related to immunity in L. vannamei was upregulated after pathogen challenges such as lectin and TCTP, meanwhile, the Toll receptor gene was downregulated. Further study should also be performed to measure the expression of the three genes in revealing the immune pathways. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Antimicrobial peptides (AMPs) are crucial in the humoral immunity aspect of invertebrates' innate immune systems. However, studies on AMP discovery in the Pacific white shrimp (Litopenaeus vannamei) using omics data have been limited. Addressing the growing concern of antibiotic resistance in aquaculture, this study focused on the identification and characterization of AMPs in L. vannamei using advanced genomic and transcriptomic techniques. The genome of L. vannamei was performed to predict and identify a total of 754 AMP-derived genes, distributed across most chromosomes and spanning 24 distinct AMP families, and further identified 236 AMP-derived genes at the mRNA level in hemocytes. A subset of 20 chemically synthesized peptides, derived from these genes, exhibited significant antimicrobial activity, with over 85% showing effectiveness against key bacterial strains such as Staphylococcus aureus and Vibrio parahaemolyticus. The expression patterns of these AMPs were also investigated in different shrimp tissues and at various infection stages, revealing dynamic responses to pathogenic challenges. These findings highlight the significant potential of AMPs in L. vannamei as novel, effective alternatives to traditional antibiotics in aquaculture, offering insights into their diverse structural properties and biological functions. Together, this comprehensive characterization of the AMP repertoire in L. vannamei demonstrates the efficacy of using omics data for AMP discovery and lays the groundwork for their potential applications. [ABSTRACT FROM AUTHOR]

Acute hepatopancreatic necrosis disease, which can cause 100% mortality, is one of the main threats to farming Litopenaeus vannamei. We identified seven strains of pathogenic bacteria from ponds with outbreaks of acute hepatopancreatic necrosis at a L. vannamei farm in Zhuhai, China. Among the seven bacteria strains, one strain was isolated from aquaculture water, two strains were isolated from hepatopancreas, and the other four strains were isolated from juvenile shrimp. The results of 16S rRNA sequencing and biochemical identification showed that all seven pathogenic bacteria were Vibrio parahaemolyticus and that they carried the pirA and pirB virulence genes. These bacteria showed ß-hemolysis with translucent rings, and six serotypes were identified. The regression infection results showed that the lethal rates of the three V. parahaemolyticus strains of serotypes O1:KUT and OUT:KUT to L. vannamei were significantly higher than those of the other serotypes. The three V. parahaemolyticus strains had the same growth characteristics, and they all entered the growth plateau at 4 h after inoculation. In addition, the pathogenicity of the three V. parahaemolyticus strains were similar. In the present study, V. parahaemolyticus was identified as one of the pathogenic bacteria causing acute hepatopancreatic necrosis of L. vannamei, and the O1:KUT and OUT:KUT serotypes may be the main pathogenic strains in Zhuhai. These results provided a foundation for the isolation, identification, and pathogenicity study of acute hepatopancreatic necrosis of L. vannamei, providing a reference for the prevention and control direction of L. vannamei disease. [ABSTRACT FROM AUTHOR]

Simple Summary: In hyperintensive culture systems, high stocking density produces excess nitrogenous wastes, which deteriorate water quality, affecting the physiology and gut microbiota of shrimp. In this study, different methodologies were used to analyze water quality, immune systems and intestinal microbiota. The results showed that bacilli and LAB, inoculated into water, utilize nitrogen in several ways, improving shrimp growth and survival. In addition, the bacteria modulate the intestinal microbiota and immune response, improving shrimp production. This is the first time that the use of Pediococcus pentosaceus and Leuconostoc mesenteroides as nitrifying bacteria has been reported. Shrimp is one of the most important aquaculture industries. Therefore, we determined the effect of nitrifying-probiotic bacteria on water quality, growth, survival, immune response, and intestinal microbiota of Litopenaeus vannamei cultured without water exchange. In vitro, only Bacillus licheniformis used total ammonia nitrogen (TAN), nitrites, and nitrates since nitrogen bubbles were produced. TAN decreased significantly in the treatments with B. licheniformis and Pediococcus pentosaceus and Leuconostoc mesenteroides, but no differences were observed in nitrites. Nitrates were significantly higher in the treatments with bacteria. The final weight was higher only with bacilli and bacilli and LAB treatments. The survival of shrimp in the bacterial treatments increased significantly, and superoxide anion increased significantly only in lactic acid bacteria (LAB) treatment. The activity of phenoloxidase decreased significantly in the treatments with bacteria compared to the control. Shrimp treated with bacilli in the water showed lower species richness. The gut bacterial community after treatments was significantly different from that of the control. Linoleic acid metabolism was positively correlated with final weight and superoxide anion, whereas quorum sensing was correlated with survival. Thus, bacilli and LAB in the water of hyperintensive culture systems act as heterotrophic nitrifers, modulate the intestinal microbiota and immune response, and improve the growth and survival of shrimp. This is the first report on P. pentosaceus and L. mesenteroides identified as nitrifying bacteria. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The experiment was conducted to investigate the effects of acute stress with different nitrite concentrations on immunity and gill Na+/K+-ATPase activity of Litopenaeus vannamei. Litopenaeus vannamei with average weight of (1.68±0.23) g were selected. The nitrite concentrations were set as 0 (Control group),0.4, 0.8, 1.6, 3.2 mg/L respectively. The acute stress test lasted for 96 h. Hepatopancreas immune function and gill Na+/K+-ATPase activity were measured at 0, 12, 24, 48, 72, 96 h, respectively. The result showed that the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), acid phosphatase (ACP), alkaline phosphatase (AKP), and lactate dehydrogenase (LDH) in the liver pancreas of Litopenopenus vannamei in stress groups showed an overall trend of increasing first and then decreasing with the extension of stress time. In the 3.2 mg/L group, the activities of SOD, CAT, GSH-Px, and ACP in the liver pancreas of Litopenopenus vannamei all dropped to the level of the control group after 96 hours of stress. The activity of LDH dropped to the level of the control group after 24 hours of stress and then continued to decrease significantly below the level of the control group (P<0.05). Except for the 0.4 mg/L group, where the content of malondialdehyde (MDA) in the hiver pancreas of Litopenopenus vannamei dropped to the level of the control group after 96 hours of stress, the MDA content in all other groups was significantly higher than that of the control group during the 96 hours of stress (P<0.05). Within 96 hours of stress, the activity of Na+/K+-ATPase in the gills of Litopenopenus vannamei in the 0.4 mg/L group continued to rise; the activity of Na+/K+-ATPase in the gills of Litopenopenus vannamei in the 0.8 to 3.2 mg/L groups showed a trend of initial activation followed by inhibition with the extension of stress time, and in the 3.2 mg/L group, it dropped to the level of the control group after 96 hours of stress. The study shows that the immune function and gill Na+/K+-ATPase activity of Litopenaeus vannamei were significantly affected under acute nitrite stress of 0.4 to 3.2 mg/L. When the salinity is (24.0±1.0) parts per thousand, it is necessary to control the nitrite content within 0.4 mg/L during the healthy aquaculture process of the Litopenaeus vannamei. [ABSTRACT FROM AUTHOR]

The present work examined the effect of different chitosan sizes (bulk and nano) on the shelf life of fillets made of Cromileptes altivelis flesh in cold temperatures. Research procedures involved the characterization of chitosan and nanochitosan from the prawn skin (the study used the Litopenaeus vannamei species) and the preservation of C. altivelis fillet in chitosan and nanochitosan solution during the cooling process. Fresh C. altivelis flesh weighing 800-950 gram were sliced into skin-off fillets before being immersed in chitosan and nanochitosan solution for 15 minutes. The flesh was then covered and stored at a cold temperature (± 5°C) for nine days with an observation interval of three days. Observations were made on the values of TVB-N, TMA-N, pH, TPC, FFA, peroxide value, and the sensory values of humpback grouper fillets. The present work employed a randomized block group with a factorial pattern. All parametric data were analyzed using the ANOVA and Duncan tests. The experiment was divided into three chitosan and nanochitosan treatments with a duration of 0 day, 3 days, 6 days, and 9 days. The results showed that chitosan and nanochitosan caused significant differences (P< 0.05) in the values of TVB-N and TPC. Similarly, a significant difference was recorded in all test parameters' storage time (P< 0.05). Using nanochitosan solution can suppress the degradation of fish fillets in terms of the TVB-N and TPC values. Moreover, the best treatment was the fillet soaked in nanochitosan solution that was stored for six days. The present work concluded that nanochitosan affects the shelf life of C. altivelis fillet during the cooling process. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigates the nutritional quality and genetic diversity of Pacific white shrimp (Litopenaeus vannamei) from three different aquaculture farms in Guangdong Province, China. We assessed the shrimp's muscle tissue for key nutrients like protein, fat, and amino acids, alongside a detailed genetic analysis. Our findings reveal that the nutritional content is consistent across all three populations, indicating the reliable protein quality and essential nutrient levels critical for shrimp health and growth. However, significant differences in genetic diversity were observed, with one population exhibiting reduced genetic diversity and signs of inbreeding. These results underscore the necessity of implementing effective breeding strategies to enhance genetic diversity and ensure the sustainable development of L. vannamei in aquaculture. This study provides essential insights for optimizing breeding practices to maintain the long-term health and productivity of this vital species in the aquaculture industry. This study aimed to evaluate the quality and genetic diversity of farmed Litopenaeus vannamei across three distinct populations from Maoming City (MM), Zhanjiang City (ZJ), and Yangjiang City (YJ) in Guangdong Province. Muscle tissues from L. vannamei were analyzed for phenotypic traits, conventional nutrients, amino acids, and fatty acids, while genetic diversity was assessed using whole genome sequencing techniques. The analysis revealed that the crude protein content in shrimp across the three populations ranged from 20.87 to 21.95 g/100 g, crude fat content ranged from 0.90 to 1.50 g/100 g, essential amino acid content ranged from 5.55 to 5.86 g/100 g, total amino acid content ranged from 14.73 to 15.27 g/100 g, total fatty acid content ranged from 682.73 to 793.97 mg/100 g, total antioxidant capacity (T-AOC) ranged from 2.68 to 2.72 μmol/g, superoxide dismutase (SOD) activity ranged from 1021.97 to 1057.21 U/g, and catalase (CAT) activity ranged from 78.65 to 81.33 μmoL/min. No significant differences were observed in ash and crude fat levels among conventional nutrients, nor in the biochemical indexes T-AOC, CAT, and SOD. Genetic analysis showed that the single nucleotide polymorphism density (SNP/Kb) ranged from 15.323 to 17.461, nucleotide diversity (π) ranged from 2.98 × 10−5 to 15.84 × 10−5, polymorphism information content (PIC) ranged from 0.300 to 0.317, heterozygosity (Ho) ranged from 0.033 to 0.048, and inbreeding coefficients (FIS) ranged from 0.834 to 0.887. The genetic differentiation index (FST) values among the three populations ranged from 0.056 to 0.106. This study provides an evaluation of the germplasm resources and genetic diversity of farmed L. vannamei, offering insights for the efficient management and sustainable utilization of this species' germplasm resources. [ABSTRACT FROM AUTHOR]

There is inconsistent toxicity of nitrite and ammonia nitrogen at different salinities and temperatures. To study the effect of nitrite, ammonia, salinity, temperature stress about Litopenaeus vannamei, this experiment is a four-factor and three-level orthogonal test of 35 days, consisting of nitrite concentration (0.05, 0.5, 5 mg/L), ammonia nitrogen concentration (0.2, 0.9, 4 mg/L), salinity (0.5, 15, 30), temperature (20, 25, 30 ℃). The results showed that with increasing nitrite and ammonia nitrogen concentrations, survival rate and body length daily growth value decreased significantly (P<0.05), serum malondialdehyde (MDA), urea nitrogen (BUN) and blood ammonia (AMM) content increased significantly (P<0.05), and superoxide dismutase (SOD) activity in hepatopancreas increased significantly (P<0.05). With increasing salinity, serum activities of alanine aminotransferase (ALT) and azelaic aminotransferase (AST) were significantly (P<0.05) lower； daily growth values of body length, daily growth values of body weight, SOD and alkaline phosphatase (AKP) activities were significantly (P<0.05) higher. With increasing temperature, survival rate decreased significantly (P<0.05), serum BUN, AMM content and SOD activity increased significantly (P<0.05). The interaction between nitrite and salinity had the greatest effect on survival rate. Salinity had the greatest effect on daily growth values of body length and body weight. Ammonia nitrogen had the greatest effect on MDA content. Nitrite had the greatest effect on BUN and AMM content, as well as SOD activity. The interaction between nitrite and ammonia nitrogen had the greatest effect on ALT, AST, ACP activity. The interaction between nitrite and temperature had the greatest effect on AKP activity. The study showed that both interaction between salinity and nitrite and the interaction between ammonia and nitrite produced synergistic effects of ALT and AST activities, with the toxic effects of nitrite playing a dominant role at low salinity. In the external environment, the antioxidant capacity of the body under co-stress was mainly affected by the contents of nitrite and ammonia nitrogen. The antioxidant capacity was weaker at 20 ℃. About growth and antioxidant function of Litopenaeus vannamei, the interaction between nitrite and ammonia nitrogen, salinity, temperature had a greater effect than single factor. The present study may provide a reliable experimental basis for a healthy and sustainable industry of Litopenaeus vannamei, and the nitrite should be controlled to be lower than 0.5 mg/L, the ammonia nitrogen to be lower than 0.9 mg/L, the water temperature to be lower than 30 ℃ [ABSTRACT FROM AUTHOR]

Nitrogenous waste is a global concern in aquatic ecosystems. In the shrimp farming system, feeding is the main input of nitrogen, which leads to the accumulation of nitrogenous waste, such as ammonia, nitrite, and nitrate. Nitrogen cycling is crucial for nitrogenous waste removal and for the stability of the aquaculture system. Under the action of different functional microorganisms, a variety of nitrogen cycling pathways can be used for the transformation and removal of nitrogenous waste. Understanding the complexity of the nitrogen cycle is necessary for improving the aquaculture environment. This review examines the many components and mechanisms involved in the nitrogen cycle in shrimp farming system, including nitrification, denitrification, anammox, heterotrophic assimilation, and autotrophic assimilation. Because of the difference in aquaculture characteristics, nitrogen cycling pathways in different shrimp culture modes are diverse. The current application of the nitrogen cycle in shrimp farming system, including the outdoor pond mode and indoor industrialized mode, was presented in combination with the requirements for dissolved oxygen (DO), organic matter, carbon–nitrogen ratio, light, and other environmental factors. Overall, nitrification, heterotrophic assimilation, autotrophic assimilation, and heterotrophic denitrification are the main nitrogen cycle processes in the shrimp culture system. According to the characteristics of aquaculture modes and microorganisms, utilizing different nitrogen cycle processes can enhance the efficiency of the nitrogen cycle, facilitate the elimination of nitrogenous waste, optimize the aquaculture water environment, and improve overall aquaculture benefits. [ABSTRACT FROM AUTHOR]

Antibiotic resistance in shrimp farms has emerged as an extremely serious situation worldwide. The main aim of this study was to optimize the cultural conditions for producing new antibiotic agents from marine Streptomyces species. Streptomyces SK3 was isolated from marine sediment and was identified by its 16S rDNA as well as biochemical characteristics. This microbe produced the highest concentration of bioactive secondary metabolites (BSMs) when cultured in YM medium (YM/2). It produced the maximum total protein (41.8 ± 6.36 mg/ml) during the late lag phase period. The optimum incubation temperature was recorded at 30 °C; BSMs were not produced at ≤10 °C within an incubation period of 3–4 days. The suitable agitation speed was found to be 200 rpm with pH 7.00. The proper carbon, nitrogen, and trace elements supplementation consisted of starch, malt extract, calcium carbonate (CaCO3), and magnesium sulfate (MgSO4). The ethyl acetate extract was found to act strongly against three vibriosis pathogens, Vibrio harveyi, Vibrio parahaemolyticus, and Vibrio vunificus, as indicated by the inhibition zones at 34.5, 35.4, and 34.3 mm, respectively. The extract showed the strongest anti-V. harveyi activity, as indicated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.101 ± 0.02 and 0.610 ± 0.04 mg/ml, respectively. Basic chemical investigation of the crude extract using thin layer chromatography (TLC), bioautography, liquid chromatography tandem mass spectrometry (LC‒MS/MS), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (1H-NMR) revealed that the active components were the terpenoid and steroid groups of compounds. They showed carboxylic acid and ester functions in their molecules. [ABSTRACT FROM AUTHOR]

Abstract The present study was designed to investigate the effects of supplementation with freeze-dried Clostridium butyricum (CB) powder on the growth, immune function and intestinal health of Litopenaeus vannamei after replacing fishmeal in the diet with cottonseed protein concentrate (CPC). Six treatment groups were designed, namely the control group (CON, 25% fish meal) and five alternative groups (CPC replacing 40% fishmeal protein in the control group). Based on the alternative group, 0%, 0.065%, 0.26%, 1.04%, and 4.16% of freeze-dried CB bacterial powder (4.6 × 108 CFU/g) were added, recorded as CB 0, CB 0.065, CB 0.26, CB 1.04, and CB 4.16, respectively. Each treatment had 3 replicates of 40 shrimps (0.29 ± 0.01 g) each and breeding for 8 weeks. After the experiment, serum enzyme activities, muscle amino acids, and intestinal parameters (short-chain fatty acids, digestive enzymes, gene expression, and microbiota) were tested to explore the effects of freeze-dried CB powder in shrimp aquaculture. The results showed that the CB1.04 group had the highest final body weight, weight gain rate, and specific growth ratio (P > 0.05). Freeze-dried CB powder increased the activity of serum superoxide dismutase, glutathione peroxidase, complement 3, and complement 4. Muscle tyrosine, proline, and total essential amino acids were remarkably increased in the CB 1.04 group (P

Abstract Our work evaluated the possible underlying roles of dietary dried seaweed (Gracilaria verrucosa; GV) on the inherent immune response, antioxidant capacity, immune-related gene expression, and protection of whiteleg shrimp (Litopenaeus vannamei) contra white spot syndrome virus (WSSV). Three hundred and sixty healthy L. vannamei (15.26 g ± 1.29 g) were graded into four supplemental groups ( Triplicate/group) and fed with diets including 0 (control), 2, 4, and 8 g GV (kg diet) −1 for 21 days. Following the feeding period, each group of shrimp received an intramuscular WSSV injection (1.4 × 106 copies/ml). Hemolymph and gills samples were collected before and after the challenge with WSSV. Notably, the administration of dietary GV significantly enhanced the innate immune parameters of pacific white shrimp including total hemocyte count (THC), phagocytosis, phenoloxidase activity, reactive oxygen species (ROS) production, and lysozyme activity before and after challenge with WSSV. Additionally, dietary supplementation of 4, and 8 g of GV (kg diet)−1 remarkably elevated ACP, AKP, SOD, GPx, and catalase activities along with a decrease in the MDA level in gills of shrimp before and post-WSSV challenge. In response to the GV supplement, significant upregulation of expression of ALF1, CRU1, PEN4, and CTL with downregulation of TRAF6, STAT, TLR1, and NOS genes was recorded in the gills tissue before and post-challenge with WSSV, especially at a dose of 8.0 GV g kg − 1. Dietary inoculated shrimp with GV revealed notably higher survival percentages after being challenged with WSSV. Conclusively, these data indicate that Gracilaria verrucosa can be recommended as a valuable supplemented seaweed to stimulate the innate immunity and enhance the health of Litopenaeus vannamei against viral infection.

The stress level of vannamei shrimp (Litopenaeus vannamei) is affected by increased density and several genes are expressed under the condition. This study aimed to determine the expression of genes encoding white shrimp stress after density treatment and the infectious myonecrosis virus (IMNV) challenge test. A completely randomized design (CRD) was carried out with 6 treatment groups, i.e. 3 different stocking density groups without IMNV infection (100, 200, and 400 shrimp/m2) and 3 different stocking density groups + IMNV infection (100, 200, and 400 shrimp/m2). In addition, a shrimp density of 400 shrimp/m2 reported the fastest rate of developing the IMNV virus as seen from the clinical symptoms. The lowest cumulative number of shrimp deaths was at a density of 100 shrimp/m2 and was caused by the IMNV virus confirmed through RT-PCR. Expression of stress-coding genes was divided into upregulated and downregulated characteristics. The upregulated genes were lectin and translationally controlled tumor protein (TCTP), while the downregulated gene was Toll Receptor. The results showed that the expression of genes related to immunity in L. vannamei was upregulated after pathogen challenges such as lectin and TCTP, meanwhile, the Toll receptor gene was downregulated. Further study should also be performed to measure the expression of the three genes in revealing the immune pathways.

Aiming to investigate the impact of different stocking densities on the ability of Pacific white shrimp (Litopenaeus vannamei) to utilize Chlorella sorokiniana (CHL), a 3 × 2 factorial design stocking experiment was used in this study. Specifically, shrimp was fed with two dietary protein sources (fishmeal [FM] and CHL) at low (LSD; 100 per m3), medium (MSD; 200 per m3) and high (HSD; 300 per m3) stocking densities for 8 weeks. The growth performance and resistance to Vibrio parahaemolyticus (1.0 × 107 CFU/mL) of shrimp decreased with the increase of stocking density, but dietary CHL improved this result. Differences between the CHL and FM groups for V. parahaemolyticus resistance were significant only under high-density conditions (P

To address the issue of the poor antioxidant and preservative effects of gallic acid (GA) on the quality of aquatic products due to its poor water solubility, a novel water-soluble GA derivative GA-CONH-SO3H was successfully synthesized and confirmed by high resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), and spectroscopy. Theoretical calculations of non-covalent interactions (NCI) revealed that GA-CONH-SO3H exhibited abundant hydrogen bonding to water molecules, with binding energy stronger that than of GA. Moreover, the measured saturation solubility of GA-CONH-SO3H in water at room temperature was 290.02 mg/mL, which was 26-fold higher than that of GA. Meanwhile, the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxy, and superoxide anion radical scavenging capacities of GA-CONH-SO3H were 92.80%, 98.09% and 99.74%, while those of GA at 58.78 μmol/L, 1.76 mmol/L and 23.51 mmol/L were only 89.77%, 49.56% and 29.89%, respectively. After 8 days of storage at 4 ℃, the pH of shrimp (Litopenaeus vannamei) soaked in GA-CONH-SO3H solution was 7.44 compared to 7.71 with GA, and after 6 days, the total volatile basic nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS) value were total viable count (TVC) were 27.07 mg/100 g, 0.87 mg/kg and (5.09 ± 0.02) (lg(CFU/g)) as opposed to 35.47 mg/100 g, 0.94 mg/kg and (5.66 ± 0.03) (lg(CFU/g)) with GA, which indicated that the preservative effect of GA-CONH-SO3H was significant. It extended the shelf life by 2 days. Additionally, GA-CONH-SO3H was significantly superior to 4-hexylresorcinol (4-HR) as a commercial fresh shrimp preservative in inhibiting the increase of TVB-N, TBARS and TVC values. Furthermore, GA-CONH-SO3H exhibited very low cytotoxicity. Therefore, GA-CONH-SO3H has great potential as an antioxidant preservative for aquatic products.

In order to extend their storage life with low cost and high quality, the application of low-intensity direct current (DC) electric fields for the microbial inactivation of Litopenaeus vannamei were investigated in this study. By applying a constant electric field ranging from 0.2 A to 0.6 A (corresponding to electric field intensities 1.6 V/cm to 5.0 V/cm), the effects of the field on the microbial inactivation and storage quality of Litopenaeus vannamei were thoroughly examined. The findings indicated that treatment at 0.4 A (corresponding to electric field intensities 2.7 V/cm to 3.0 V/cm) for 20 minutes reduced the total viable count by 1.90 lg CFU/g, while maintaining a stable and controllable system temperature without significant changes in the sample's texture characteristics (P>0.05). The detection results during storage revealed that the electric field treatment not only inhibited the growth of microorganisms, but also significantly delayed (P

This study aimed to assess the water culture supplementation of fermented prebiotic (mannanoligosaccharide, MOS) and probiotic (Bacillus subtilis WB60) on water quality parameters, growth performance, feed utilization, immunity response, intestinal microbes, and histological investigations of Pacific whiteleg shrimp (Litopenaeus vannamei) challenged with Vibrio parahaemolyticus. Shrimp juveniles (4.98 ± 0.11 g) were distributed into four experimental groups (twelve 1 m3 hapa, 25 shrimps/m3/each hapa, 3 triplicates/group). The first group (G0) used only fermented B. subtilis at a rate of 0.2 g/acre. The 2nd, 3rd, and 4th groups contained the same constant level of B. subtilis (0.2 g/acre) with three different levels of fermented MOS at 25, 50, and 75 g/acre (G1, G2, and G3, respectively). The results showed that TAN and NH3 values were significantly lower in all fermented groups compared to G0. Increasing the levels of fermented MOS led to significant improvements in growth performance, feed utilization, shrimp biomass, survival rate, crude protein, and ash content (p < 0.05). Compared to G0, the values of SOD, CAT, and IgM were significantly improved, while MDA levels were significantly decreased in all fermented MOS levels (p < 0.05). The G3 group exhibited the highest values of immune responses, including total hemocyte count, phagocytic activity, phagocytic index, respiratory burst activity, and lysozyme activity, as well as phenol oxide activity and total aerobic bacteria compared to the other groups (p < 0.05). Moreover, the G2 and G3 groups showed significantly lower mortality (30%) of shrimp challenged with V. parahaemolyticus infection compared to G0. In conclusion, the commercial scale recommends using fermented MOS and B. subtilis (50–75 g/acre) as water culture additives for shrimp L. vannamei due to the improvements in growth performance, feed utilization, immunological, and antioxidant indicators. [ABSTRACT FROM AUTHOR]

Glycogen and lipid accumulation and mobilization exhibited significant variations among different tissues of female Litopenaeus vannamei during ovarian maturation, yet the underlying mechanism remained incompletely elucidated. This study was conducted to elucidate the distinctive differences in glycogen and lipid accumulation and mobilization throughout the ovary maturation process (stages II–V) in L. vannamei. Our findings revealed that during ovarian maturation, the ovary consistently accumulated substantial amounts of glycogen and fatty acids, which were actively mobilized not only from the hepatopancreas and muscle but also from their ovary synthesis. Moreover, a significant downregulation trend (P < 0.05) among all tissues was observed in glycogen and lipids metabolism-related genes and ILPs/AKT/PI3K signaling pathway–related genes. Consequently, we proposed that stages II–III represent the active period of rapid glycogen and lipid accumulation and mobilization in L. vannamei compared to stages IV–V. These results provided deeper insights into the mechanisms governing glycogen and lipid accumulation and mobilization during ovarian maturation in L. vannamei. [ABSTRACT FROM AUTHOR]

The biological effects of different particle sizes of bioflocs on Litopenaeus vannamei remain unclear. A 4-day short-term stress response experiment was conducted with small-sized group (SG), medium-sized group (MG), and large-sized group (LG), which were treated with bioflocs, and a control group (CG) treated with clear water. The diameters of the median particle size of SG, MG, and LG were 93.19 μm, 139.83 μm, and 173.09 μm, respectively; besides, the diameters of the coarse telomere of SG, MG, and LG were 181.40 μm, 279.60 μm, and 372.52 μm, respectively. The pathological observation of paraffin sections indicated varying degrees of tissue damage in SG, MG, and LG when compared with CG, with SG exhibiting more evident damage characterized by the presence of high-density vacuoles in the gill lumen. The activity of alkaline phosphatase and phenol oxidase exhibited varying degrees of fluctuation in all groups, with SG exhibiting a consistent downward trend. The activity of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, was enhanced by the influence of bioflocs. Additionally, the content of malondialdehyde in SG was significantly higher than that in MG and LG after 2–4 days of stress (P < 0.05). Gill transcriptome analysis showed that CA, PDIA3, V-ATPase, and genes related to oxidative phosphorylation pathway and tricarboxylic acid cycle were significantly up-regulated under the stimulation of bioflocs. Compared with MG, MHC, TnI, and GS were significantly down-regulated in SG. Compared with LG, DanjC9 was significantly down-regulated in SG. Overall, the results showed that the short-term biological effects of small-sized bioflocs on L. vannamei were the strongest. [ABSTRACT FROM AUTHOR]

To evaluate effects of microalga addition in the intensive Litopenaeus vannamei farming system, the amount of Picochlorum sp. in culture water was adjusted to be 1 × 104 cells/mL (KH_1), 2 × 104 cells/mL (KH_2), or 4 × 104 cells/mL (KH_4) respectively by artificial addition, and that without microalgal addition was set as the control. First, it was found that Picochlorum sp. addition was effective to reduce the total ammonia nitrogen (TAN), nitrite, phosphate, and chemical oxygen demand (COD) in culture water, and the water quality of KH_4 was the best among various groups after a 30-day culture, with reduction of 89.85% TAN, 78.17% nitrite, 50.00% phosphate, and 63.28% COD in comparison with the control. Second, addition of Picochlorum sp. had a significant impact on the microalgae community structure of shrimp culture system, and it has become the absolute dominant genus in KH_1, KH_2, and KH_4 group, with relative abundances of 86.57%, 95.48%, and 99.01% respectively, whereas Chaetoceros (51.05%) dominate in the control. Moreover, the growth performance of shrimp in KH_2 and KH_4 groups were better than those in the control (P < 0.05), and the superoxide dismutase (SOD) and lysozyme (LZM) activity in hepatopancreas increased by 31.73–78.05% and 16.93–73.74% for the Litopenaeus vannamei in KH_2 and KH_4. The results of this study indicated that artificial addition of Picochlorum sp. could be effective to improve the water quality and shrimp growth, and be a feasible environmental regulation method in shrimp aquaculture. [ABSTRACT FROM AUTHOR]

The genetic parameters for growth and multiple-stress resistance in Litopenaeus vannamei at 7 and 15 weeks of age were estimated using sixty full-sib families (including 29 half-sib families) in the present study. The heritability of growth traits was estimated to be medium to high (0.256 ± 0.119 to 0.441 ± 0.124), and that of multiple-stress [simultaneous stress of high salt (35), low pH (6 ± 0.1) and high ammonia nitrogen (56 mg/L)] tolerance traits was low (0.029 ± 0.034 to 0.053 ± 0.058), suggesting the feasibility of selecting increasing growth traits and that genetic improvement of stress tolerance traits requires multi-generation breeding by family and intra-family selection. The genetic correlations of growth traits (body weight, total length, body length, carapace length, carapace width and abdominal length) at identical ages were high (0.855 ± 0.031 to 0.999 ± 0.0002) (P < 0.01). The highly significant correlations between growth traits showed that any growth trait could be replaced by other growth traits for indirect selection. The genetic correlations between growth traits and multiple-stress tolerance traits at identical ages were low, but the positive correlation (0.081 ± 0.129 to0.224 ± 0.125) indicated that selection of growth traits will have a positive correlation response to multiple-stress tolerance traits. There was a weak genetic positive correlation (0.285–0.342) (P < 0.05) in the growth traits between the two different age stages, however the genetic correlation in the multiple-stress tolerance traits between the two different age stages were low and not significant (P > 0.05).This suggests that selection for growth traits in L. vannamei at an early age may not be optimal and should be undertaken at later stages of growth. [ABSTRACT FROM AUTHOR]

The technology of post-larval farming is increasingly being valued by aquaculture farmers and enterprises. The objective of this study is to determine an appropriate temperature restriction mode through temperature training to achieve greater compensatory growth potential. We cultured PL whiteleg shrimp (Litopenaeus vannamei) at either low (25℃) or high (31℃) temperature for 20 days (restriction stage) and then transferred them to a control temperature (28℃) for 20 days (compensation stage). The compensatory growth observed under low temperature restriction showed that shrimp can recover and exhibit over-compensatory growth after growth restriction. Specific growth ratio and enzyme activity analyses indicated that the shrimp required 10 days or more to adapt to temperature stress. The relative expression levels of hsp60, tor, and s6k in the low temperature group were downregulated during the early stage of the restriction period, but were continually upregulated during the compensation period. This result indicates that although short-term restrictions may lead to growth retardation, growth will resume as the temperature recovers. When shrimp were challenged with Vibrio parahaemolyticus E1, the damage caused by infection after low temperature restriction and compensation was delayed and not severe. This indicates that the disease resistance of shrimp was improved after low temperature restriction. In contrast, shrimp in the high temperature group showed more severe damage than those in the control group at all time points after pathogen infection, indicating that high temperature restriction made the shrimp more susceptible to pathogenic Vibrio. Transcriptome analysis revealed abundant pathways related to energy metabolism, amino acid biosynthesis, protein synthesis, and cell growth in the low temperature restriction-recovery group, which highlighted the importance of optimizing the nutrient supply, especially protein and amino acid to enhance compensatory growth. In summary, after 20 days of low temperature training, PL shrimp exhibited significant compensatory growth, which not only promoted the growth, but also enhanced the body's resistance to V. parahaemolyticus. Therefore, this culture technique can be used for aquaculture practices in PL shrimp cultivation. [ABSTRACT FROM AUTHOR]

5-Aminolevulinic acid (5-ALA) is an endogenous non-protein amino acid and has been used as a new type of growth promoter in aquaculture feed. This study explored the effects of 5-ALA on growth and intestinal health in juvenile shrimp, Litopenaeus vannamei. Shrimps were fed diets containing five different 5-ALA levels (0, 15, 30, 45, and 60 g/t) for 90 days. A concentration of 45 g/t 5-ALA significantly improved growth metrics, including the specific growth rate, protein efficiency, and feed conversion (P < 0.05). The optimal concentration of 5-ALA was 38.3 g/t, as indicated by broken-line regression. Dietary supplementation with 5-ALA increased the crude protein content of whole shrimp, but had no significant effect on the moisture, ash, or crude lipid content (P > 0.05). Suitable supplementation of 5-ALA (45 g/t, 60 g/t) improved the activities of the digestive enzymes alpha-amylase, pepsin, trypsin, and lipase, thus promoting digestion and absorption. Shrimp fed with 45 g/t 5-ALA had increased levels of essential amino acids in the muscles and a higher proportion of polyunsaturated fatty acids in the hepatopancreas. Supplementation with 45 or 60 g/t 5-ALA upregulated the expression of genes related to growth and molting, including chitinase, ecdysone receptor, retinoic X receptor, calcium/calmodulin-dependent protein kinase I, heat shock protein 60, and heat shock protein 70. Moreover, dietary supplementation with 5-ALA affected the abundance of intestinal flora, increased the number of beneficial bacteria, and improved intestinal health. These results indicated that 5-ALA may significantly benefit shrimp health and aquaculture productivity, providing a novel theoretical basis for further research into 5-ALA as a dietary supplement. [ABSTRACT FROM AUTHOR]

Abstract In recent decades, probiotics have become an acceptable aquaculture strategy for shrimp growth promotion and immune modulation. This study aimed to evaluate the effect of Bacillus velezensis on Litopenaeus vannamei following a 60-day trial. L. vannamei (3 ± 0.4 g) were distributed into four groups with three replicates per group and fed an isonitrogenous diet supplemented with B. velezensis at 0, 1 × 107, 1 × 108, and 1 × 109 CFU/g, which were defined as the control, G1, G2, and G3 groups, respectively. B. velezensis significantly improved the growth, survival rate, and proximate body composition of L. vannamei (P

The efficacy of Chromolaena odorata leaf flour components (CO) to increase the growth performance, non-specific immune activity, and resistance against Vibrio parahaemolyticus of whiteleg shrimp (Litopenaeus vannamei) culture was evaluated. To this purpose, whiteleg shrimp post larvae were fed on diets supplemented with 0 and a 1.5 g CO/kg diet for 45 days in a pond. After feeding trials, the shrimps were identified for their growth parameters, collected, and injected with V. parahaemolyticus, then their non-specific immune activity and resistance to V. parahaemolyticus was observed for 14 days. Findings showed that CO increased the average body weight (7.71 g, 37%), weight gain (7.69 g, 40%), and specific growth rate (13.23%/day, 5.7%) as compared to the control. In addition, CO supplementation also increases shrimp’s hematologic and immune activity (total hemocyte counts [6.8 × 107 CFU/mL, 242.9%], differential hemocyte counts [27%, 142.1%], and prophenoloxidase activity [0.085%, 566.7%]). Finally, shrimp resistance to V. parahaemolyticus infection also increased after CO supplementation, with survival rates of 73.33% as compared to 23.33% for the control. It suggests that C. odorata leaf flour component supplementation at an optimal dose in the diet may be an effective strategy to increase growth and resistance to bacterial disease with reduced mortality in shrimp farms.

Abstract 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

This study investigated the effects of different concentrations (0.1%, 0.3%, 0.5%, 0.8% and 1.0% by mass relative to shrimp meat) of hyaluronic acid (HA) on the gel and physicochemical properties of surimi made from Litopenaeus vannamei. The results showed that adding a certain amount of HA improved the textural characteristics, gel strength, brightness and whiteness of shrimp surimi gel, promoted the transformation of free and immobilized water into bound water, and increased the water-binding characteristics and water-holding capacity. Rheological analysis showed that addition of a certain amount of HA improved the storage moduli of shrimp surimi, but low concentrations of HA could have adverse effects on the apparent viscosity. Chemical force analysis showed that ionic bonds first decreased and then increased, while hydrogen bonds exhibited the opposite trend with the addition of HA. An appropriate amount of HA could improve hydrophobic interactions but the formation of disulfide bonds from sulfhydryl oxidation was also inhibited by HA. Moreover, HA could interact with shrimp surimi proteins, inhibit the formation of protein polymers, change the conformation of proteins, and promote the transformation of the secondary structure of proteins from α-helix to β-structure and random coil. The microstructure of shrimp surimi gel was improved by adding an appropriate amount of HA, becoming more uniform and denser. Among all samples with different levels of HA, shrimp surimi gel with the addition of 0.8% HA had the highest hardness, gumminess, chewiness, gel strength, storage modulus and the densest microstructure, and its water-holding capacity significantly improved when compared with that of the control group (P < 0.05). However, the textural characteristics, gel strength, water-holding capacity and storage modulus of shrimp surimi gel with 0.1% HA were lower than those of the control group, and the microstructure was looser.

Abstract Background Expansion of genomic resources for the Pacific white shrimp (Litopenaeus vannamei), such as the construction of dense genetic linkage maps, is crucial for the application of genomic tools in order to improve economically relevant traits. Sexual dimorphism exists in Pacific white shrimp, and the mapping of the sex-determination region in this species may help in future reproductive applications. We have constructed male, female, and sex-averaged high-density genetic maps using a 50 K single-nucleotide polymorphism (SNP) array, followed by a genome-wide association study (GWAS) to identify genomic regions associated with sex in white shrimp. Results The genetic map yielded 15,256 SNPs assigned to 44 linkage groups (LG). The lengths of the male, female, and sex-averaged maps were 5,741.36, 5,461.20 and 5,525.26 cM, respectively. LG18 was found to be the largest for both sexes, whereas LG44 was the shortest for males and LG31 for females. A sex-determining region was found in LG31 with 21 statistically significant SNPs. The most important SNP was previously identified as a sex-linked marker and was able to identify 99% of the males and 88% of the females. Although other significant markers had a lower ability to determine sex, putative genes were intercepted or close to them. The oplophorus-luciferin 2-monooxygenase, serine/arginine repetitive matrix protein and spermine oxidase genes were identified as candidates with possible participation in important processes of sexual differentiation in shrimp. Conclusions Our results provide novel genomic resources for shrimp, including a high-density linkage map and new insights into the sex-determining region in L. vannamei, which may be usefulfor future genetics and reproduction applications.

This experiment aimed to evaluate the impact of dietary hydroxyproline (Hyp) supplementation on the muscle quality of juvenile Pacific white shrimp (Litopenaeus vannamei) fed a low fishmeal diet. Six formulated diets included one high fishmeal (HF; 25% fishmeal content) and five low fishmeal diets (10% fishmeal content) with 0%, 0.2%, 0.4%, 0.6% and 0.8% Hyp (LF0, LF2, LF4, LF6 and LF8, respectively). Each diet was assigned to four replicates, and 40 shrimp (0.32 ± 0.00 g) per replicate were fed four times a day for 8 weeks. Dietary Hyp supplementation had little effects on growth performance, but increased the contents of Hyp, prolyl 4-hydroxylases (P4Hs), and collagen. The meat yield, springiness, hardness, chewiness, and cohesiveness of muscle were the highest in the LF4 group among the low fishmeal groups (P < 0.05). Cooking loss and freezing loss of muscle were the lowest in the LF4 group (P

This study was conducted to evaluate the effects of Monascus purpureus M-32 fermented soybean meal (MFSM) on growth, immunity, intestinal morphology, intestinal microbiota, and intestinal metabolome of Pacific white shrimp (Litopenaeus vannamei). Four groups of diets were formulated, including control group (30% fish meal and 30% soybean meal [SBM] included in the basal diet) and three experimental groups which MFSM replaced 20% (MFSM20), 40% (MFSM40), and 60% (MFSM60) of SBM in control group, respectively. Results showed that the soluble proteins larger than 49 kDa in MFSM were almost completely degraded. Meanwhile, the crude protein, acid-soluble protein, and amino acid in MFSM were increased. The results of shrimp culture experiment showed that the replacement of SBM with MFSM decreased FCR (P

[Objective] To establish a simple, rapid and visual pathogen detection method for shrimp, and to achieve self detection by fishermen. [Method]The specific primers of LAMP (loop-mediated isothermal amplification technique) were designed for decapod iridescent virus 1 (DIV1). After optimizing the conditions of reagent dosage, temperature and reaction time, a visual and rapid detection method of LAMP combined with hydroxynaphthol blue (HNB) was established. [Result] 12 mmol/ L Mg2+ and 250 μmol/ L HNB solution in the LAMP reaction system was the most suitable condition at 65 ℃ for 60 min. The minimum detection limits of LAMP-HNB of DIV1 was 10² copies/ μL plasmid. The stability and specificity of the detection of DIV1 had also been verified using positive plasmids with target genes, and the results of 16 repeated experiments were relatively stable, multiple template amplification experiments did not show false positives, which meets the experimental requirements. [Conclusion] The LAMP-HNB visualization rapid detection method established in this study is suitable for the on-site rapid detection of shrimp DIV1 mentioned above. [ABSTRACT FROM AUTHOR]

[Objective] To analyze the diversity and structure of sediment microbial flora in the middle and later stages of greenhouse recirculating-water aquaculture of Litopenaeus vannamei. [Method] The sediment samples were collected from the pond of L. vannamei on the 50, 65,80,95 and 110 days in the greenhouse recirculating-water aquaculture of L. vannamei. The characteristics and diversity of microbial communities in water environment were analyzed by using 16S rRNA high-throughput sequencing technology. [Result] In the middle and late stages of breeding, Proteobacteria and Bacteroidetes were the main dominant bacteria, and the relative abundance reached the highest values (84. 96% and 38. 08%) at 50 and 65 d respectively. At the level of the genus, Pelagibacter, Arcobacter, Rhodobacteraceae-unclassified were the dominant genera, Pelagibacter of Alphaproteobacteria was the common dominant group in the late stage of breeding (95 and 110 d), and its relative abundance reached 41. 02% at 110 d. There was no obvious dominant genus at 80 d. Shannon-Wiener diversity index showed a trend of first increase and then decrease, it reached the highest level at 80 d (7. 24). Principal component analysis and cluster analysis showed that the bacterial diversity of the samples collected at these two points had the highest similarity, and the bacterial diversity of the samples collected at other time points had no obvious difference. [Conclusion]The research results showed that the circular water aquaculture system could optimize the microbial community environment in the aquaculture water of L. vannamei, improve the structure and diversity of the water microbial flora, which had an important guiding role for the actual aquaculture production of L. vannamei. [ABSTRACT FROM AUTHOR]

LED light source has the advantages of energy saving and environmental protection, high photoelectric conversion efficiency, which can meet the demand for green, efficient and intelligent development of factory farming. To investigate the effect of LED culture lights on the muscle quality of Litopenaeus vannamei in the biofloc system, two treatment groups were set up:the LED light group (L group) and the natural light group (N group). The culture experiments were conducted over an 8-week period, utilizing larvae L. vannamei as the study material. The larvae had a mean body length of 5. 23±0. 61 cm and a mean body mass of 1. 52± 0. 47 g. The illumination parameters of the L group were a mixture of blue- green light ( green light 545 nm, blue light 450 nm); the photoperiod was 15L ∶9D; the light intensity was 2 000 Lx. The experimental results showed that there were no significant differences in conventional nutrients (moisture, crude protein, crude fat, ash) between L group and N group ( P > 0. 05). A total of 18 amino acids were detected in muscle. The contents of threonine (Thr), tyrosine ( Tyr), arginine (Arg), glycine (Gly) and ∑EAA/ ∑NEAA in the muscles of the L group were significantly higher than those of the N group (P < 0. 05). There were no significant differences in the contents of essential amino acids (EAA), semi- essential amino acids (HEAA) and aromatic amino acids (DAA) (P>0. 05). A total of 37 fatty acids were found in muscle. The contents of C12:0, DHA and EPA+DHA in the muscle of shrimp from the L group were significantly higher than those from the N group (P<0. 05). The contents of C21:0, C20:3n-3, C20:3n-3 and C22:5n-6 were significantly lower than those in the N group (P<0. 05). The results indicate that the LED light parameter could improve the nutritional quality of the muscle of L. vannamei. [ABSTRACT FROM AUTHOR]

The use of measures to prevent disease and enhance immune competence in shrimp is essential to ensure the sustainability of shrimp aquaculture. We assessed here differences in the immunological status of juvenile Litopenaeus vannamei reared in a mature chemoautotrophic biofloc system (BFT.C) compared to a less stable heterotrophic biofloc system (BFT.H). After 72 days of culture, we examined different standard hemato-immunological parameters (hemograms, phenoloxidase activity, total serum protein concentration, and hemolymph agglutination capacity), the expression of 50 immune-related genes in the midgut, and the transcriptional 16S rRNA levels of the predominant bacterial groups associated with the shrimp gut. Overall, BFT.C demonstrated greater environmental stability than BFT.H, leading to enhanced immunocompetence in the animals. Biofloc-reared shrimp showed enhanced Vibrio agglutination, indicating a superior ability to identify and immobilize bacterial invaders in the hemolymph. Besides, four genes involved in antimicrobial and antiviral defenses (Litvan ALF-A, Lvan-Stylicin1, LvPPAE2, and LvDicer1) showed to be differentially transcribed at basal levels in the midgut of shrimp from both systems of biofloc maturation. Finally, the 16S rRNA transcriptional profiling revealed a greater abundance and viability of Actinobacteria and Firmicutes in the midgut from shrimp reared in BFT.C and BFT.H, respectively. In conclusion, our study evidenced that the biofloc maturation system impacts both hemolymph- and intestine-based immunities of shrimp as well as their midgut bacterial communities. These findings may help to understand how the environment, shrimp immunity, and the bacterial microbiome interact to prevent disease in shrimp farming. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effectiveness of synbiotic microcapsules through feed on growth performance and immune response of Pacific white shrimp (Litopenaeus vannamei) in field testing during IMNV disease outbreaks and fluctuating weather. Four groups of shrimps (4.11 ± 0.05 g) with four replicates were fed with different doses of synbiotic microcapsules SIN 0 (0%), SIN 0.5 (0.5%), SIN 1 (1%), and SIN 1.5 (1.5%) for 60 days with a feeding frequency of 4 times a day (07.00, 11.00, 15.00, and 19.00) based on a feeding rate from 4% (w/w) for average body weight < 4 g, 3% (w/w) for average body weight 4–10 g, and reduced until 2% (w/w) for average body weight 10–25 g, depending on the feed index adapting to operational standards procedures for Pacific white shrimp cultivation production from PT Steladus. The synbiotic microcapsules consisted of prebiotic mannan oligosaccharide/MOS, probiotic Pseudoalteromonas piscicida (1UB), and Bacillus cereus (BR2). This study focused on parameters of growth performance (survival rate/SR, specific growth rate/SGR, feed conversion ratio/FCR), immune response (total hemocyte count/THC, differential hemocyte count/DHC, respiratory burst/RB, phenoloxidase/PO activity, phagocytic activity/PA), microbiology (total bacterial count/TBC, 1UB + BR2 TetR count, total Vibrio count/TVC), and histopathology. The results showed significant results that synbiotic microcapsules increased SR, SGR also reduced FCR with the best results in SIN 1.5 (SR: 93.50 ± 1.30%, SGR: 4.83 ± 0.01% days−1, and FCR: 1.16 ± 0.02). Immune response of THC, RB, PO, and PA in the synbiotic microcapsule treatment showed higher values with the best results in the SIN 1.5 treatment, while DHC had no significant difference. TBC, 1UB, and BR2 TetR count values increased until the 60th day, with the highest value in the SIN 1.5, while TVC showed the lowest value in both intestinal and hepatopancreas organs. Histopathological results showed that hepatopancreas and intestinal organs experienced tissue damage in all treatments, with synbiotic microcapsules showing less damage when compared to SIN 0. In conclusion, supplementation of dual-species synbiotic microcapsules through feed can improve growth performance and immune response and suppress Vibrio during the outbreak with the best dose of 1.5% synbiotic microcapsules. [ABSTRACT FROM AUTHOR]

Sexually dimorphic traits such as growth and body size are often found in various crustaceans. Methyl farnesoate (MF), the main active form of sesquiterpenoid hormone in crustaceans, plays vital roles in the regulation of their molting and reproduction. However, understanding on the sex differences in their hormonal regulation is limited. Here, we carried out a comprehensive investigation on sexual dimorphic responses to MF in the hepatopancreas of the most dominant aquacultural crustacean—the white-leg shrimp (Litopenaeus vannamei). Through comparative transcriptomic analysis of the main MF target tissue (hepatopancreas) from both female and male L. vannamei, two sets of sex-specific and four sets of sex–dose-specific differentially expressed transcripts (DETs) were identified after different doses of MF injection. Functional analysis of DETs showed that the male-specific DETs were mainly related to sugar and lipid metabolism, of which multiple chitinases were significantly up-regulated. In contrast, the female-specific DETs were mainly related to miRNA processing and immune responses. Further co-expression network analysis revealed 8 sex-specific response modules and 55 key regulatory transcripts, of which several key transcripts of genes related to energy metabolism and immune responses were identified, such as arginine kinase, tropomyosin, elongation of very long chain fatty acids protein 6, thioredoxin reductase, cysteine dioxygenase, lysosomal acid lipase, estradiol 17-beta-dehydrogenase 8, and sodium/potassium-transporting ATPase subunit alpha. Altogether, our study demonstrates the sex differences in the hormonal regulatory networks of L. vannamei, providing new insights into the molecular basis of MF regulatory mechanisms and sex dimorphism in prawn aquaculture. [ABSTRACT FROM AUTHOR]

Introduction: Screening excellent bacterial strains for fermentation is the key to improving the nutritional value and bioavailability of soybean meal (SBM). This study investigated the application of Bacillus subtilis-fermented soybean meal (FSBM) on the feed of Pacific white shrimp (Litopenaeus vannamei). Methods: FSBM was used to replace 0%, 25%, 50%, 75%, and 100% fish meal, and the feeding trial was lasted for 8 weeks (initial weight: 0.9 g). Results and discussion: The amino acid profile in the whole shrimp body was tested. FSBM substitution only significantly reduced the content lysine in whole shrimp body, but increased the content of arginine. Fatty acid data showed that the content of n-6 PUFAs in whole shrimp was significantly increased by FSBM substitution. In muscle, FSBM substitution significantly reduced the content of MUFAs, but increased the content of PUFAs including C18:3n-3, C18:2n-6 and C20:4n-6. No hepatopancreas structure modifications appeared in the 25% group compared with the control group. Subsequently, we investigated the response patterns of different organs to FSBM substitution from antioxidant, endoplasmic reticulum stress and immunity. A high proportion of FSBM significantly reduced the content of GSH in hemolymph and hepatopancreas, while increased the mRNA expression of cat. FSBM substitution did not affect the activities of antioxidant enzymes in the intestine. However, the mRNA expression level of hsp70 in the intestine was significantly reduced by FSBM. In terms of immunity, the mRNA expression levels of lgbp and penaeidin in the hepatopancreas showed a significant linear increase trend. In muscle, high proportion of FSBM significantly increased the mRNA expression of imd. FSBM substitution did not significantly affect the expression of immune genes in the intestine. In terms of endoplasmic reticulum stress, FSBM substitution significantly increased the mRNA expression of eif2a in the hepatopancreas. In muscle, FSBM substitution inhibited the mRNA expression of bip. In the intestine, FSBM replacing 75% of fish meal significantly increased the mRNA expression of bip and ire1. In summary, this study indicated that when the fish meal content account for 40% in diets (dry weight), the screened Bacillus subtilis-FSBM can replace 25% of fish meal protein without reducing the antioxidant and immune abilities of shrimp. [ABSTRACT FROM AUTHOR]

Hot water extract of Chlorella vulgaris (CVE) is a biologically substance that enhances organism's immune function and antioxidative capacity. This study evaluated the effect of supplementation with various concentrations of CVE on muscle nutritional components, non-specific immunity, antioxidation, and resistance to non-ionic ammonia (NH3-N) stress in Litopenaeus vannamei over 45 days using diets supplemented with CVE at five different concentrations (0%, 0.5%, 1%, 5%, 10%, and 15%). Specifically, fresh and sweet amino acids (Asp, Glu) significantly increased (P < 0.05) in shrimp fed the 1% CVE diet, reaching 18.12 g/kg and 33.08 g/kg, respectively. Bitter amino acids (Leu) and Hypoxanthine (Hx) significantly decreased (P < 0.05) in shrimp fed the 1% CVE diet, at 10.56 g/kg and 10.56 ug/g. CVE supplementary enhanced the activities of acid phosphatase, alkaline phosphatase, and nitric oxide synthase while decreasing malondialdehyde levels. Shrimp fed with a 1% CVE diet exhibited significantly higher enzyme activity than the control group under NH3-N conditions (P < 0.05). Overall, this study demonstrated that 1% CVE as a feed additive significantly improved the muscle mass, boosted immunity and reduced the stress response to NH3-N in L. vannamei. This research provides a valuable reference for the application of CVE as a feed additive in crustacean aquaculture. [ABSTRACT FROM AUTHOR]

Salinity is a crucial environmental factor influencing the survival, growth, development, and reproduction of aquatic animals. However, the underlying molecular mechanisms of the shrimp's response to salinity stress are not yet fully understood. Therefore, we used the Illumina NovaSeq 6000 platform to perform transcriptome sequencing of the hepatopancreas of Litopenaeus vannamei under high-salinity (30 PSU), medium-salinity (10 PSU), and low-salinity (0.5 PSU) conditions. We obtained 63.23 Gb of high-quality data and identified 3589 differentially expressed genes (DEGs), including 1638 upregulated and 1951 downregulated genes. Notably, a comparison between the control group (30 PSU) and the low-salinity group (0.5 PSU) revealed that the BBOX1 and CHE1 genes were significantly upregulated, while the ACOX1, MPV, CYP2L1, GCH, MVK, TREt1, and XDH genes were significantly downregulated. These genes are primarily involved in key metabolic pathways, such as fatty acid oxidation, cholesterol metabolism, and hormone synthesis and metabolism. The key genes involved in fatty acid β-oxidation, such as ACOX1, ACAD, HADH, HSD17B4, PECR, CROT, PIPOX, and CG5009, all showed a downward trend, suggesting that L. vannamei may respond to salt stress by regulating fatty acid oxidative metabolism, optimizing energy utilization, and maintaining cell homeostasis under low-salinity conditions. Functional annotation of gene ontology (GO) and KEGG pathway enrichment analysis highlighted the roles of these significant DEGs in the adaptation of L. vannamei to environments of varying salinity, underscoring the importance of metabolic pathways in their adaptive physiological responses. This study provides a crucial molecular biological basis for understanding the molecular mechanisms and physiological protection strategies of L. vannamei under salinity stress. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]