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The study aimed to assess the impact of stocking density on the growth performance, survival rate and production of seabass (Lates calcarifer) fingerlings in floating net cages conducted at the Maheshkhali Channel, Cox's Bazar, Bangladesh. A triplicate group of seabass, with an average initial weight of 86.82 ± 1.9 g, was randomly stocked in floating net cages at densities of 15, 12, 10 and 8 fish m−3, referred to as T15, T12, T10 and T8, respectively. The fish fingerlings were supplied with freshly chopped sardine (Sardinella fimbriata) at 10% of their body weight for 4 months and 5% for 2 months, administered twice daily. The water quality metrics were measured fortnightly. The initial and the final proximate composition of seabass was not significantly different (p > 0.05). Upon completion of the experiment on the 180th day, the growth performance and additional measures, including final body weight, weight gain (WG), percent weight gain (PWG), specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency ratio (FER), survival rate and total production, were assessed. Comparisons of growth and yield demonstrated that fish stocking density significantly (p < 0.05) influenced growth and productivity. Fish cultivated at maximum density (T15) exhibited lower mean weights than those raised at lower densities. This study demonstrated that T10 had better results for all growth and other metrics examined, indicating the appropriateness of this density. Therefore, it may be inferred that seabass exhibits optimal growth at a stocking density of 10 fish m−3 along the coast of Cox's Bazar, Bangladesh. [ABSTRACT FROM AUTHOR]

This study aimed to improve the production environment for the Nile tilapia (Oreochromis niloticus) through developing a new automatic feeding system (AFS), focusing on optimizing water physicochemical parameters, fish growth rates, and the economic viability of the Nile tilapia farming. The experiment was conducted using six fiberglass tanks, each with a capacity of 0.25m³. Three of these tanks were equipped with a new AFS, while the other three utilized a conventional AFS. A total of 150 fingerlings, each with an initial weight of 13.50g, were randomly distributed at a density of 25 fish per tank. Throughout the duration of the experiment, water quality parameters were systematically measured and recorded. The fish were fed with a sinking commercial diet containing 30% crude protein, administered at a rate of 5% of their body weight. The obtained results revealed statistically significant differences (P<0.05) between the two AFSs, with the newly developed AFS exhibiting an improved water quality, enhanced growth rates, and a greater economic viability. [ABSTRACT FROM AUTHOR]

Simple Summary: Identification and counting of fish are relevant tools for managing the stocking, harvesting, and marketing of farmed fish. Researchers have used convolutional networks for these purposes and employed various approaches to improve network learning. Batch normalization is one technique that enhances network stability and accuracy. The study aimed to evaluate machine learning for identifying and counting pirapitinga Piaractus brachypomus fry with different batch sizes. The researchers used one thousand photographic images of Pirapitinga fingerlings, labeled with bounding boxes. They trained the adapted convolutional network model with batch normalization layers inserted at the end of each convolution block. The training involved one hundred and fifty epochs, with batch sizes for normalization set to 5, 10, and 20. Identifying and counting fish are crucial for managing stocking, harvesting, and marketing of farmed fish. Researchers have used convolutional networks for these tasks and explored various approaches to enhance network learning. Batch normalization is one technique that improves network stability and accuracy. This study aimed to evaluate machine learning for identifying and counting pirapitinga Piaractus brachypomus fry with different batch sizes. The researchers used one thousand photographic images of Pirapitinga fingerlings, labeled with bounding boxes. They trained the adapted convolutional network model with batch normalization layers added at the end of each convolution block. They set the training to one hundred and fifty epochs and tested batch sizes of 5, 10, and 20. Furthermore, they measured network performance using precision, recall, and mAP@0.5. Models with smaller batch sizes performed less effectively. The training with a batch size of 20 achieved the best performance, with a precision of 96.74%, recall of 95.48%, mAP@0.5 of 97.08%, and accuracy of 98%. This indicates that larger batch sizes improve accuracy in detecting and counting pirapitinga fry across different fish densities. [ABSTRACT FROM AUTHOR]

The purpose of the current study was to assess the effect of dietary supplements of either aqueous (AE) or ethanolic (EE) (Juniperus communis) leaf extracts on growth performance, intestinal health, hemato-biochemical indices, antioxidant, inflammation cytokine responses, and resistances against infection in Nile tilapia, Oreochromis niloticus. Fish groups were controlled with no extract (J1) and fed diets (J2, J3, J4, and J5) containing 1.0 and 2.0 g/kg aqueous and ethanolic extract for 60 days. Fish were given an intraperitoneal injection (IP) of Aeromonas hydrophila for 10 days after the feeding trial; then, the fish mortality was recorded. Growth, feed efficiency, and activity of endogenous enzymes (lipase, trypsin, chymotrypsin, and amylase) were significantly improved in all dietary J. communis groups, especially in J5, compared to other groups. Also, J5 showed the highest absorption area, muscularis, goblet cells, villi width, and fewer gut bacterial counts than the other groups. In addition, the J4 and J5 groups of tilapia fish exhibited a significant increase in the levels of total protein, serum albumin, globulin, hemoglobin, white blood cells, and hematocrit (P < 0.05), as well as a significant decrease in the levels of serum alanine, aspartate aminotransferases, glucose, and cholesterol compared to the J1 groups. Moreover, the J4 and J5 fish showed a significant decline in the levels of MDA with improvements in antioxidant (SOD, CAT, and GPX) and immunological (lysozyme, immunoglobulin M, and complement C3) indices compared to the J1 group. Fish in J4 and J5 exhibited downregulated levels of il-8, il-10, il-1β, tnf-α, ifn-γ, and hsp70 genes compared to other groups. In contrast, hepatic catalase (cat), superoxide dismutase (sod), and interleukin (il-10) gene expressions were upregulated. The lowest fish mortality after the bacterial challenge was recorded in the J5 group. These findings suggest that 2.0 g/kg feed ethanolic extract of J. communis-fed Tilapia fish fingerlings improved their growth and intestinal health, boosted their immune systems and antioxidant responses, and increased their resistance to A. hydrophila. [ABSTRACT FROM AUTHOR]

The intestine is the principal digestive organ which is generally divided into three segments as the proximal intestine (PI), the mid intestine (MI), and the distal intestine (DI) in fish. In this study, the role of dietary vitamin D3 (VD3) in regulating the function and health of different intestinal segments was evaluated in grass carp (Ctenopharyngodon idella) fingerlings through the supplementation with the increasing levels of dietary VD3 (0, 500, 1000, 1500, 2000, and 2500 IU/kg). The results showed that VD3 supplementation (1000–2000 IU/kg) significantly enhanced the fish growth performance, and the correlation analysis suggested that this effect was positively correlated with intestinal somatic index (ISI) and intestinal length index (ILI) of MI and DI except PI. In support of this finding, dietary VD3 enhanced the activities of digestive and brush border enzymes in the fish mainly in MI and DI rather than PI. Furthermore, the intestinal microbiota analysis revealed that VD3 increased the abundance of intestinal flora at the genus level rather than the phylum level. Meanwhile, hematoxylin and eosin staining presented that VD3 supplementation reduced epithelial goblet cell hyperplasia and lamina propria edema compared with the VD3 deficiency group in the MI and DI. Further studies showed that feeding VD3 decreased malondialdehyde levels but increased total antioxidant capacity, glutathione levels, and total superoxidase activity in MI or DI but not PI, suggesting the antioxidant potential of VD3 in two intestinal segments. Moreover, in MI and DI but not PI, dietary VD3 suppressed pro-inflammatory cytokine (il1 β and tnf α ) but enhanced antimicrobial peptide (hepcidin and βdefensin) mRNA levels and increased the activities of immune-related enzymes (lysozyme and acid phosphatase), highlighting the ability to improve fish immunity. Corresponding to these effects, dietary VD3 was able to mediate NF-E2-related factor 2 (Nrf2) and NF-κB pathways in MI and DI. Finally, quadratic regression models based on weight gain (PWG), feed efficiency (PE), ISI, and ILI suggested that the appropriate VD3 requirements for grass carp fingerlings were 1233.70–1387.11 IU/kg. Taken together, our findings strengthened the potential of dietary VD3 in managing the functions and health of particular intestinal segments and provided valuable reference data for VD3 requirements of fingerling fish. [ABSTRACT FROM AUTHOR]

Objective: A genetically distinct strain of Walleye Sander vitreus (southern Minnesota strain [SMS]) persists in southern Minnesota lakes despite decades of stocking more easily obtained strains from outside of the region. Because of the regional performance advantage inferred by this persistence, we conducted in situ experiments to compare survival and stocking cost of SMS Walleye fry against those of a frequently stocked northern Minnesota strain (Mississippi headwaters strain [MIS]) to determine whether it is beneficial to expand SMS fry stocking in lieu of historic practices. Methods: We conducted four paired stockings of oxytetracycline‐marked SMS fry and MIS fry into six southern Minnesota lakes and then sampled the fish as fall fingerlings during 2018, 2019, 2021, and 2022. We then used fluorescent microscopy and parentage‐based tagging techniques to discern the stocked strains for comparison of growth and survival. We also obtained production and stocking cost data from agency records to calculate relative stocking costs. Result: By the end of their first summer, SMS Walleye from all but two stockings exhibited higher survival than MIS Walleye. Despite higher initial costs to produce SMS fry, their higher survival to fall fingerlings made the stocking of SMS fry more cost effective than MIS fry stocking. Natural reproduction was also identified in several stocked lakes, most of which consisted of either high or increasing levels of SMS ancestry. Conclusion: A local strain can outperform nonlocal strains at a level that can overcome additional costs of developing a new egg source. In addition, natural reproduction of local‐strain Walleye may reduce or eliminate the need for future stocking. Impact statementWe show that a local Walleye strain can outperform nonlocal strains at a level that can overcome additional costs of developing a new egg source. In addition, higher natural reproduction of the local strain may reduce or eliminate the need for future stocking. [ABSTRACT FROM AUTHOR]

Present study aimed to evaluate the dietary impact of commercial zinc oxide (ZnO) nanoparticles (NPs) on the growth performance of commercially important fish fingerlings. A 90-days feeding trial was carried out to evaluate the impact of dietary supplementation of commercial ZnO-NPs on the growth performance and survival rate of commercially important fish of carp family-rohu (Labeo rohita) fingerlings (2.23±0.38g in average weight and 5.74±0.28 cm in average length). ZnONPs (Sigma-India) supplemented feed was prepared at a concentration (10, 100, 200 mg/kg) and experimental fish fingerlings were exposed for 90 days. Mid-term, fish fingerlings were randomly sampled every 30 days from both the dietary exposed and unexposed groups to assess growth parameters, including weight gain (WG), weight gain percentage (WG%), specific growth rate (SGR), and feed conversion ratio (FCR). After 90 days of feeding, the results indicated that the ZnO inclusion diet at a concentration of 100 mg/kg significantly improved growth performance, with a weight gain of 5.50±0.51g, weight gain percentage of 143.6±53.22%, and FCR of 1.41±0.32, compared to other treatment and control groups. [ABSTRACT FROM AUTHOR]

Objective: We sought to assess the efficacy of feeding tocotrienol, a member of the vitamin E family, as it impacts physiological functions in fingerling fish. Methods: Fingerling Largemouth Bass Micropterus nigricans with an initial mean body weight (±SD) of 0.98 ± 0.09 g were fed five diets containing tocotrienol at 0, 10, 20, 30, and 40 mg/kg (T0, T10, T20, T30, and T40 diets, respectively) for 42 days. After the feeding experiment, fish were challenged with Largemouth Bass ranavirus (LMBV) and monitored for 48 h. Result: Findings indicated a positive impact of tocotrienol‐supplemented diets on fingerling survival. Furthermore, the weight gain and specific growth rate of fish that received the T30 and T40 diets were significantly higher than those of fish that were fed the T0 diet. Tocotrienol supplementation improved the protein efficiency ratio and condition factor and increased the whole‐body lipid and protein content. Conversely, the hepatosomatic index, viscerosomatic index, and feed conversion ratio were significantly decreased by tocotrienol supplementation. Fish that were fed the T30 and T40 diets exhibited significantly higher hepatopancreas lipase activity and intestinal protease activity. Generally, superoxide dismutase and catalase activities in the liver increased as the tocotrienol level increased. Additionally, the liver malondialdehyde concentration decreased, and there was an improvement in the structure of liver cell tissue. Survival at 48 h after the LMBV challenge was significantly higher in fish that were fed the T30 and T40 diets compared to fish that were given the T0 diet. Maximum specific growth rate was observed at a tocotrienol concentration of 33.63 mg/kg. Conclusion: Results suggest that supplementation of Largemouth Bass fingerling diets with appropriate quantities of tocotrienol can enhance survival, growth, antioxidant capacity, digestion, and uptake of nutrients as well as disease resistance. Impact statementThe survival and growth performance of Largemouth Bass fingerlings were improved by adding tocotrienol at a concentration of 33.63 mg/kg in the diet. [ABSTRACT FROM AUTHOR]

This experiment was performed to identify the influence of dietary Saussurea lappa root (SLR) on the performance and general health status of Nile Tilapia fingerlings (O. niloticus). Four formulated diets with different SLR levels of 0.0, 2.5, 5 and 10 g/kg, respectively, were afforded to fingerling fish (15.42 ± 0.05 g) for 8 weeks. The feed efficiency ratio (FER), feed intake (FI) and feed conversion ratio varied with dietary SLR level in a linear model and a high feed efficiency rate was recorded at the 10 g/kg group, while FI and FCR exhibited an opposite trend (P < 0.001). Dietary SLR level influenced serum protein constituents, liver and renal function enzymes, triglycerides, cholesterol and glucose (P < 0.001). Serum Catalase (CAT), total antioxidant capacity (T‐AOC) and superoxide dismutase (SOD) remarkedly increased with dietary SLR level and attained a level at 10 g/kg. Furthermore, serum lysozyme, complement C3 (C3), IgA and IgD were stimulated by 10 g/kg SLR. Intestinal digestive enzymes (lipase and amylase) increased with SLR level up to 10 g/kg. As the dietary SLR level raised, the cumulative survival percentage aginst A. hydrophila challenge increased and then reached a maximum at 10 g/kg SLR group. Moreover, gene expression of pro‐inflammation cytokines (TNF‐2a, IL‐1β, and IL‐10) in liver and kidney transcriptomes demonstrated effective immunostimulant capabilities of greater SLR inclusion levels in fish diet. Meanwhile, intestinal microbial investigation, revealed that high levels of SLR in tilapia fish feed significantly suppressed total bacterial count, and pathogenic bacterial count (such as, E. coli, Coliform, Aeromonas spp, Pseudomonas spp.), and stimulated lactic acid bacteria development. Finally, it is recommended to include a high level of SLR (5 or 10 g/kg) in the diet of O. niloticus fingerlings to enhance feed efficiency, antioxidant characteristics, and immunological response against bacterial infections. [ABSTRACT FROM AUTHOR]

The ectoparasitic copepod Lernaea cyprinacea (anchor worm) has more than 100 host species among teleost fishes and affects cyprinids both in fish farms and natural waters. In addition, while L. cyprinacea infection in amphibians has been recorded in Asia, North and South America, there is no data available in the literature on their presence in Europe. In this study, we first reported L. cf. cyprinacea parasitising an anuran tadpole in Europe. Specimens of L. cf. cyprinacea were observed attached to a tadpole of the agile frog (Rana dalmatina), which was caught during fishing of crucian carp fingerlings (Carassius carassius) from a small fish pond in Hungary during the summer of 2012. The infected tadpole was collected from a rearing pond, where juvenile crucian carps were kept. The tadpole was inspected in the laboratory, and digital photos were taken. The parasites were found attached to the body-tail junction and to the leg of the tadpole (at Gosner stage 41). The parasite species was identified as L. cf. cyprinacea based on morphological traits. [ABSTRACT FROM AUTHOR]

Simple Summary: This study was carried out to examine how different diets with vitamin solutions/vitamin premixes and plant oils (algae and fungi oils) affect the reproduction of Pangasius catfish broodstock, growth performance, and survival rates of fish larvae and fingerling. The experiment was designed as a factorial setup, with Pangasius catfish broodstock fed six different diets in triplicate groups of ten fish (three males and seven females) cultured in separate hapa nets in an the earthen pond for about two months. Results showed significant differences among the six tested diets. Diets containing 35% CP, supplemented with 0.6% vitamin solutions and 1.26% algal oil, produced the best results in terms of the highest growth performance, reproductive indices, and fingerling survival rates. These findings provide valuable information for Pangasius catfish farmers and the fish production industries in the Mekong Delta, Vietnam. This study evaluates the effect of different diets supplemented with vitamin solutions on Pangasius catfish broodstock reproduction, growth performances, and the survival rates of fish larvae and fingerling. The growth and reproductive performances of breeders fed with different test diets showed significant differences among the six tested diets (p < 0.05). The highest final body weight (FBW), weight gain (WG), daily weight gain (DWG), specific growth rate (SGR) of broodstock, and survival rate of Pangasius fingerlings were found in Treatment 5, which contained 0.6% H-OVN mixed with 12.6% algal oil, and Treatment 3, which contained 0.6% vitamin premix H-OVN. The average gonadosomatic index (GSI), relative fecundity index (RFI), fertilized eggs, hatching rates of eggs, and survival rate of fingerlings was 9.1 ± 2.8 (6.7–12.8%), 133,224 ± 39,090 (104,267–199,512 eggs/kg), 77.9 ± 22.2 (62.2–93.6%), and 45.3 ± 17.4 (22.0–66.3%), respectively. The findings of this study showed that the diet containing 35% CP contents supplemented with 0.6% vitamin premix H-OVN mixed with algal oils showed the highest results in terms of growth, reproductive performance indices, and survival rates of Pangasius catfish fingerlings. [ABSTRACT FROM AUTHOR]

The spotted scat (Scatophagus argus) is an important ornamental species with sexually biased ornamental values that favor males. Therefore, it makes sense to breed mono-male fingerlings as ornamental fish. The spotted scat has an XX/XY sex determination system; therefore, the first step in producing genetically all-male offspring should be the induction of a fertile sex-reversed XY pseudo-female, which would then be mated with a normal XY male to produce a YY super-male. However, the XY pseudo-female produced by estradiol (E2) treatment failed due to ovarian malformations. Here, male to female sex reversal was induced in spotted scat through a combination of E2 and an androgen inhibitor (trilostane, TR). Spotted scat fingerlings of approximately 2.8–3.5 cm were fed a diet containing both E2 (300 µg/g) and TR (300 µg/g). The fish were treated for 90 days and then fed a normal diet until they reached one year of age, when they were sampled. Twenty-eight treated XY individuals were identified using sex-linked markers. According to their gonadal histological characteristics, these treated XY fish could be divided into three groups: males with testes (n = 21), intersex individuals with ovaries–testes (n = 3), and fully sex-reversed individuals with ovaries (n = 4). All treated XX fish (n = 8) developed into normal females. There were no obvious abnormalities in the ovaries of the XY sex-reversed fish compared to the treated XX fish. Serum 11-ketotestosterone (11-KT) levels were significantly lower in XY-reversed females and treated XX females than in XY males. Compared with XY male fish, the expression of female (42sp50, foxl2, figla, zar1, and zp2) and male (dmrt1, gsdf, amh and cyp11b2) biased genes was up- and down-regulated, respectively, in the gonads of XY-completely sex-reversed fish. Immunohistochemical results indicate that 42Sp50 was expressed in oocytes of XY-partially and completely sex-reversed fish, while strong Gsdf signals were mainly detectable in testicular somatic cells of XY-partially sex-reversed fish and XY male fish. XY females were successfully produced by the combined treatment of E2 and TR in the spotted scat. Their fertility will be tested in the future. [ABSTRACT FROM AUTHOR]

Especially in arid regions, developing tilapia culture with the ability to survive a wide range of salinities is crucial due to the limited availability of fresh water for aquaculture. The present study focused on evaluating the growth performance of Nile tilapia in a biofloc system under three salinity levels: 0 (BFT0), 4 (BFT4), and 8 g/L (BFT8). Fingerling fish were raised for 37 days in tanks with a water volume of 140 liters and a stocking density of one fish per liter. The results of the water quality parameters showed that dissolved oxygen and pH decreased with increasing salinity. Furthermore, the BFT8 group had the highest concentrations of settled solid (19.98 ml/L) and total suspended solid (428.37 mg/L), while the BFT8 group had the lowest TAN concentration (4.32 mg/L). The final weight and specific growth rate were significantly higher in the BFT8 and BFT4 groups compared to the BFT0 group. Survival rates were not significantly different across treatments, and all of them were higher than 97%. The protein and lipid content of Nile tilapia bodies and bioflocs decreased with increasing salinity, while the ash content increased. The highest body ash content in Nile tilapia (13.81% of dry weight) and bioflocs (31.78% dry weight) was found at 8 g/L salinity. Based on the present study, it is suggested that salinities of 4 and 8 g/L can improve water quality, growth performance, survival, and carcass composition of Nile tilapia fingerlings in the biofloc system. This finding suggests that brackish waters can be utilized for sustainable aquaculture for the rearing of Nile tilapia. [ABSTRACT FROM AUTHOR]

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Objective: The Largemouth Bass Micropterus salmoides is an important freshwater fish that is native to the southeastern United States and is cultured for conservation, food, and for the sports fishing industry. Francisella orientalis is a globally distributed bacterial pathogen of warmwater fish species and is associated with granulomatous inflammation and high mortalities. Outbreaks of piscine francisellosis in the United States have been reported in only a few fish species. This study describes three case presentations of francisellosis in Largemouth Bass from a public display system in north‐central Florida. Additionally, laboratory‐controlled immersion challenges using an F. orientalis isolate from tilapia Oreochromis spp. evaluate susceptibility of Largemouth Bass fingerlings to F. orientalis infection and mortality through this exposure route. Methods: Necropsy, histologic examination, immunohistochemistry, bacterial recovery and culture, and quantitative polymerase chain reaction were used as diagnostic tools to evaluate both the affected display fish and the immersion‐challenged fingerlings. Result: Although the display fish and immersion‐challenged fingerlings presented with nonspecific clinical signs, gross and histological changes were indicative of granulomatous disease. Immunohistochemical and molecular testing methods confirmed F. orientalis infection in affected fish. Conclusion: The three case presentations described here mark the first reporting of naturally occurring piscine francisellosis in Largemouth Bass that were held in a public display exhibit. Additionally, causality was proven in the Largemouth Bass fingerlings through the immersion challenges. These findings demonstrate susceptibility through immersion‐based exposure and assert that francisellosis should be considered among the list of differential diagnoses for Largemouth Bass with granulomatous disease. Impact statementLargemouth Bass are the most popular Florida freshwater sport fish and are also commonly raised in hatcheries and displayed in public aquaria. Disease can threaten the health and longevity of both wild and managed fish populations, making it important to identify infectious and emerging diseases, including those caused by bacteria. The discovery of new diseases in Largemouth Bass can illuminate opportunities for improved management and husbandry practices pertaining to this species. [ABSTRACT FROM AUTHOR]

Background: Fish in aquatic environments are end consumers of the food chain and are widely used for the evolution effects of environmental pollution and their interactions in aquatic ecosystem. Objective: In the present study, common carp (Cyprinus carpio) fingerlings were selected to assess the potential risk and aquatic toxicity of meloxicam as a non‐steroidal anti‐inflammatory and a commonly used pharmaceutical drug. Methods: In order to evaluate meloxicam toxicological effect on haematological, antioxidant status, enzymological and histological parameters, based on its LC50 24 h acute toxicity (10.05 mg L−1), fish fingerlings were exposed to four doses of meloxicam including; 0 (control), 0.1 (low), 1 (medium) and 2 mg L−1 (high) under static bioassay method for 28 days. Results: The results showed that sublethal doses of meloxicam significantly decreased alanine aminotransferase, alkaline phosphatase, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) levels in comparison with the control group after 28 days (p < 0.05). However, red blood cell, haematocrit, haemoglobin and malondialdehyde values in fish exposed to meloxicam significantly increased alongside its concentration (p < 0.05) more than the control group after 28 days. SOD, CAT and GPX mRNA expression levels in gill, liver, kidney and brain organ of fish under meloxicam treatment were significantly down‐regulated compared to the control group (p < 0.05). Histopathological assessment showed the increased vacuolation in hepatocytes in liver of fish exposure to medium and high doses of meloxicam. Conclusion: In conclusion, meloxicam induces oxidative stress in common carp which results a disruption of physiological and health status of this species based on our current findings. [ABSTRACT FROM AUTHOR]

The present research work was done to elucidate tomato vegetable plant growth cultivated in a floating raft aquaponics system with rohu and tilapia fishes. The experiment was conducted for 60 days in two treatments i.e., plant+rohu fish (T1) and plant+tilapia fish (T2). The replications (10) containing 400 L water stocked with fish fingerlings in the ratio of 1:1 (plants and fish) were reared to follow the standard cultivation methods, e.g., aeration, supplementary feeding, water exchange, etc. and growth measurements were taken every 15 days. The findings show that initial and final growth of 13.763 cm and 25.643 cm of plants were noted in T1, whereas 13.581 cm and 22.467 cm were recorded in T2. The net gain in plant growth was 11.880 cm in T1 and 8.886 cm in T2. Similarly, these findings indicated the increasing order 2.314<2.621<3.010<3.935 and 1.462<1.966<2.547<2.911 of plant growth at fortnightly intervals in T1 and T2, respectively. On the basis of these findings, it can be concluded that the growth of the tomato plant was more in T1 compared to T2 and plant growth in T1 and T2 variation was significant (p<0.05) may be due to more nitrogenous compounds released by the fish waste. [ABSTRACT FROM AUTHOR]

Therapeutically popular controlled release-enabling technology has forayed into the nutrition sector. Polymer coated forms of L-methionine used in soy protein diets, and its intermediate metabolite, S-adenosyl-L-methionine, used in myriad of medical conditions have proved more efficacious over (highly catabolized) free forms. In this premier study, L-methionine-loaded chitosan nanoparticles (M-NPs) were synthesized using ionic gelation method and their efficacy was evaluated. Biophysical characterization of the NPs was done using a Nanopartica SZ 100 analyser, transmission electron microscopy, and Fourier transform infrared spectroscopy. The M-NPs were spherical and smooth and 218.9 ± 7.4 nm in size and in vitro testing confirmed the controlled release of methionine. A 60-days feeding trial in L. rohita fish fingerlings was conducted. A basal diet suboptimal (0.85%) in methionine was provided with one of the supplements as under: none (control), 0.8% chitosan NPs (0.8% NPs), 1.2% L-methionine (1.2% M) (crystalline free form), 0.6% M-NPs and 1.2% M-NPs. While the addition of 0.6% M-NPs to the basal diet complemented towards meeting the established dietary requirement and resulted in significantly highest (P < 0.05) growth and protein efficiency and sero-immunological test scores (serum total protein, serum globulin, serum albumin: globulin ratio, phagocytic respiratory burst/NBT reduction and lysozyme activity), 1.2% supplementation in either form (free or nano), for being 0.85% excess, was counterproductive. Liver transaminases and dehydrogenases corroborated enhanced growth. It was inferred that part of the methionine requirement in nano form (M-NPs) can confer intended performance and health benefits in animals relying on plant proteins-based diets limiting in this essential amino acid. The study also paves the way for exploring chitosan NPs-based sustained delivery of amino acids in human medical conditions. [ABSTRACT FROM AUTHOR]

Probiotics play vital roles in improving growth, survival, and immune responses and inhibit the growth of pathogenic bacteria in freshwater fish. This study was conducted to isolate potential probiotics from Channa punctatus and Channa striatus and to evaluate their effect on Labeo rohita fingerlings. Among the isolates, Bacillus paramycoides PBG9D and BCS10 (1) exhibited antimicrobial activity against the fish pathogen Aeromonas hydrophila. Both strains showed tolerance to acidic and alkaline pH (2, 3, 4, 7, and 9) and bile salts (0.3%) and exhibited strong adhesion capacity. After in-vitro assessment, these strains were evaluated on the growth performances of rohu fingerlings challenged by Aeromonas hydrophila for 4 weeks. The study consisted of six groups, each containing 6 fish. Group (I) was the control, fed a basal diet; group (II) contained a pathogen and was also fed a basal diet; group (III & IV) was given a probiotic supplemented experimental diet; Fourth group (V & VI) contained a pathogen and was given a probiotic supplemented experimental diet. After the 12th day of experiment, rohu fingerlings of pathogen (II) and probiotic + pathogen (V & VI) groups were intraperitoneally injected with 0.1 mL of Aeromonas hydrophila. After 4 weeks, no significant differences in weight gain, weight gain %, and feed conversion ratio were observed in probiotic (III & IV)- fed groups compared to control. However, the specific growth rate was significantly improved in probiotic fed groups compared to other groups. Survival rate and condition factor were significantly similar in all groups. After injection, abnormal swimming, loss of appetite and weight loss were observed in the pathogen (II) group, while no such symptoms were found in the probiotic + pathogen (V & VI)- groups, confirming the effects of probiotics. The overall results of the study revealed that dietary supplementation with Bacillus paramycoides strains could improve the specific growth rate and disease resistance against Aeromonas hydrophila in Labeo rohita. [ABSTRACT FROM AUTHOR]

In mariculture, often the locations of fish hatcheries and farming are distantly situated, and hence, there is a need to transport the seeds/seedlings to a longer distance with maximum survival rate. In the present study, length and weight of fingerlings, duration of starvation, packing density, water volume, water temperature and oxygen level in the packing bags were standardized to ensure maximum survival during transportation. The cobia fingerlings with mean length and weight of 48±12 mm and 3.0±1.0 g, respectively were transported for a duration 48 h at 25 °C with 100 % survival at a packing density of 2.5 fingerlings per litre (L) (7.5±2.5 g/L). Similarly, silver pompano fingerlings with mean length and weight of 24±0.48 mm and 0.6±0.08 g, respectively were transported for a duration of 48 h at 25 °C with 100 % survival at a packing density of 18.75 fingerlings/L (11.25±1.9 g/L). Experiments on bulk transportation of pompano fingerlings in 1000 litres capacity HDPE tanks containing 600 litres of seawater with continuous aeration using oxygen cylinders fitted in a transportation vessel revealed that the silver pompano fingerlings can be transported for a duration of 48 h at 25 °C and 5 - 6 ppm dissolved oxygen concentration with 100 % survival at a packing density of 8.3 fingerlings/L (4.98±0.8 g/L). [ABSTRACT FROM AUTHOR]

Rapidly increasing hatchery-raised Nile tilapia (Oreochromis niloticus) in most developing countries lack informed recommended fingerling weight for stocking in semi-intensive grow-out ponds. The current study assessed the growth performance, survival and productivity of all-male Nile tilapia fingerlings of 0.2 g, 1 g, and 5 g in an on-farm experiment. The final mean weight of fingerlings stocked at size 5 g was significantly higher (113.80±4.21 g) (P<0.05) compared to the 0.2 g (36.99±1.14 g) and 1g (91.93±5.59 g) fingerling sizes. The mean daily weight gain was highest in 5 g stocked fingerlings (0.91±0.04 g day -1) resulting in significant differences in the final mean weight. The coefficient of correlation between fish body length and weight was high and positive ranging (R=0.95-0.98). Significantly low percent survival was recorded in 0.2 g stocked fingerlings (64.4 3±1.93%). The net annual fish yield (NAY) and profit index (PI) were significantly lower at the 0.2 g. The highest NAY and PI were recorded in the 5 g stocked fingerlings (8.59±0.09 tons ha-1 year-1 and 6.6±2.08), respectively. Thus, with appropriate Nile tilapia fingerling weight at stocking, fish farmers can maximize fish growth, yield and profits. [ABSTRACT FROM AUTHOR]

Crowding stress in intensified aquaculture system reduces growth of fish. However, dietary pineapple peel ethanolic extract derived bioactive compounds are expected to minimize stress with augmented fish production. Therefore, a 60-day study with dietary pineapple peel ethanolic extract (PPEE) at 0, 0.5 and 1 % levels evaluated growth performance and physio-immunological responses of Labeo rohita fingerlings reared under different stocking densities (10, 15 and 20 fish/75 L). Fish fingerlings (405 numbers) of 4.15 ± 0.006 g were distributed among nine groups in triplicate following 3 (PPEE level) × 3 (stocking density) factorial design. Three isonitrogenous (30 % crude protein), isolipidic (6 %) and isocaloric (370 kcal DE/100 g) diets were prepared and fed respective groups on satiation basis twice daily. High stocking density significantly (p < 0.05) reduced final body weight, weight gain percentage, specific growth rate, hepatic IGF-1 expression, whole-body crude protein, lipid and total carbohydrate, intestinal protease and lipase activities, serum proteins and total immunoglobulin and respiratory burst activity (NBT) and increased feed conversion ratio and hepatic superoxide dismutase and catalase activities of fish. However, irrespective of stocking density, 1 % dietary PPEE could enhance the growth performances and physio-immunological responses of fish. In conclusion, feeding of PPEE at 1 % level can sustain intensified aquaculture production. • Crowding stress reduced growth, antioxidant status and immunological responses of Labeo rohita fingerlings. • Crowding stress caused down-regulated expression of the hepatic IGF-1 gene in fish. • Dietary supplemented pineapple peel ethanolic extract (PPEE) could minimize crowding stress in fish. • 1 % dietary PPEE could be the most effective level to alleviate crowding stress mediated negative impacts on fish. [ABSTRACT FROM AUTHOR]

In intensive culture fish cannot digest the plant-based diets properly and negatively affects their overall performance. Addition of organic acids in plant-based diets and their salts improves the performance of C. carpio. Current research was conducted to estimate the influences of dietary Tau addition in linseed meal-based diet on growth, hematological indices and carcass composition of common carp fingerlings. C. carpio fingerlings were fed (@4% of live wet body weight) on linseed meal-based diet supplemented with graded levels (0, 2, 4, 6, 8 and 10 gkg-1) of dietary taurine for 60 days. The linseed meal-based diets were given to triplicate groups of fish fingerlings (6.22 g average initial body weight) twice a day. Fish fed with linseed meal supplemented with Tau at 4gkg-1 indicated maximum retention of CHO, CP as well as gross energy as compared to fish in control treatment. Growth performance of fish was significantly improved (p<0.05) by dietary Tau up to optimal level of 4gkg-1, after which a noticeable decline in fish growth was observed due to poor retention of various essential nutrients and minerals while, EE absorption was maximum at 6gkg-1 diet. Maximum weight gain (18.31) and survival (97.78) were found maximum at 4gkg-1 level based diet. Similarly, best values of various hematological indices i.e., RBCs, Hb, PCV, MCHC, MCH were also found at 4gkg-1 diet. These results indicate that the taurine supplementation at 4gkg-1 level is most suitable for highest fish performance as well as its ability to combat various pathogens. [ABSTRACT FROM AUTHOR]

Use of microalgae as a source of food in aquaculture production is gaining recognition due to their rapid growth rate that promises high biomass generation within a short time. The challenge faced is getting good and inexpensive nutrients source to be used in mass production of the required microalgae. This study investigated the effect of different nutrient combination in influencing the growth rate of the of the green algae Oocystis sp. which has been identified as a possible protein source for the raising of Orechromis niloticus fingerlings for fish farming. Modified Bolds 3 N Medium and commercial agricultural fertilizers (urea, NPK and DAP) media were compared to establish the appropriate combinations that would result into high biomass generation but at the lowest cost possible. The Modified Bold 3 N Medium acted as the control, at a cost of 11.28 KSh per litre; the other media were derived from urea, NPK, and DAP (varying the ratio of each) at a cost of treatment 1 (0.14 KSh per litre), treatment 2 (0.18 KSh per litre), and treatment 3 (0.22 KSh per litre). The algae was cultured for 5 weeks with samples taken daily for biomass analyses using chloropyhll-a concentration as the surrogate for Oocystis sp. biomass for 30 days, from each treatment was determined. The growth rate, doubling time, and divisions per day were then estimated based on this chlorophyll-a concentration. The results showed that the mean concentrations of chlorophyll-a in treatment 1 was highest (7.715 ± 0.667 µg/ml), while treatment 3 (6.441 ± 0.555 µg/ml) had the least. There were no significant differences in the mean concentrations of chlorophyll-a in the four treatments (Kruskal–Wallis H test: P > 0.05). The chlorophyll-a concentration varied significantly in each treatment with time (Kruskal–Wallis H test: P < 0.001). There was no significant difference in the growth rate (Kruskal–Wallis H test: P > 0.05), divisions per day (Kruskal–Wallis H test: P > 0.05), and doubling time (Kruskal–Wallis H test: P > 0.05) from the different treatments. The results of this study showed that inorganic fertilizers can be used as cost-effective media in the mass scale culture of Oocystis sp. [ABSTRACT FROM AUTHOR]

Gamma-aminobutyric acid (GABA) is a four-carbon neurotransmitter and plays a major role in an increasing feed intake and nutrient utilization in aquatic animal. GABA used as a feed additive to determine its effect on Labeo rohita fingerlings growth, haemato-immunological status, antioxidant enzymes activity and expression of ghrelin and IGF-I gene. A 60-day experiment was conducted to test five isonitrogenous (CP 35%), isolipidic (CL 6%) and isoenergetic (383 kcal/100 g) diets with varying level of GABA viz., 0 (control), 25 (T1), 50 (T2), 75 (T3) and 100 (T4) mg/kg of GABA respectively. The 225 fingerlings with 15 fish/tank (ave.b.w. = 6.05 ± 0.20 g) were randomly distributed in five treatments with having three triplicate each following a CRD. The T3 group had significant (p < 0.05) higher WG%, SGR and PER than T2, T4, T1 and control treatment groups. However, opposite trend was observed in case of FCR. Similarly, the T3 group showed the significantly higher blood Hb, RBC, PCV, total protein, albumin and globulin content as compared to control and other treatment groups. However, WBC, A/G ratio, glucose, cortisol and whole-body composition did not affected. In comparison to the control and T1, T2 and T4 treatment groups, the SOD and catalase activity in the liver and gills were considerably reduced in the T3 group. The T3 treatment group was shown to have the highest levels of ghrelin and IGF-I mRNA expression in the brain and liver, respectively. According to second-order polynomial regression analysis, the highest SGR and expression of IGF-I were determined between 65 and 72 mg/kg inclusion level of GABA. The diet containing 68 mg/kg GABA level is therefore determined to be the best inclusion for promoting maximal growth and feed utilization in L. rohita fingerlings. [ABSTRACT FROM AUTHOR]

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Present research work was conducted to measure the effects of tertiary metals mixture (Fe+Zn+Mn) on superoxide dismutase (SOD) activity in various tissues of two major carps, Cirrhina mrigala and Labeo rohita at controlled laboratory conditions. 90-day-old fingerlings of both fish species were exposed to 1/4th and 1/5th of their respective 96-hr LC50 value of Fe+Zn+Mn mixture, for 24 days. After 6, 12, 18, and 24-day exposure, fish from each treatment will be sampled, dissected and their tissues viz. brain, gills, kidney, and heart isolated for the SOD enzyme assay. The physical and chemical parameters of test media viz. pH, temperature, dissolved oxygen, total hardness, carbon dioxide, total ammonia, magnesium, and calcium were determined on a 12-hourly basis. It was observed that with an increase in metal concentration, the activity of enzymes increased significantly in both fish species which was maximum at 1/4th of LC50< with the mean value of 49.35±10.04 UmL-1 in C. mrigala. In Labeo rohita, SOD activity decreased with an increase in exposure duration. SOD activity was maximum on day 6 at 52.22±12.91 UmL-1, and on day 24, it was minimum at 35.01±6.91 UmL-1. Among the organs, the SOD activity followed the trend: gills > heart > kidney > brain. The various tissues of metals mixture treated fish Cirrhina mrigala showed significantly increased activity of SOD in comparison to Labeo rohita. All the physicochemical parameters varied significantly at p<0.05 during this study period. [ABSTRACT FROM AUTHOR]

Mycobacteriosis caused by Mycobacterium fortuitum is becoming the main problem in giant gourami culture because of significant morbidity and mortality, which restricts the development of giant gourami aquaculture. The oral vaccination strategy was evaluated as a means of immunizing fish at the fingerling stage of production when fish possess a more complete immune response. A completely randomized design (CRD) consisting of four treatments which were 105, 107, and 109 CFU of killed M. fortuitum per gram of feed was given to fish for 14 days, using a nonvaccinated control. On the 31st day, the fish were challenged by 106 CFU/fish of pathogenic M. fortuitum. The results of this study indicated that orally vaccinated fish showed a significantly higher relative percent survival and immune responses (p < 0.05), compared to the nonvaccinated control fish. The relative survival rates of fish vaccinated with 105, 107, and 109 CFU g−1 feed were 69.23%, 96.15%, and 96.15%, respectively. This value was suitable for protecting fish against M. fortuitum. The best oral concentration vaccine was 107 CFU g−1 feed with an RPS value of 96.15%. The administration of M. fortuitum oral vaccine to giant gourami through commercial feed was effective in increasing immunity, relative survival, and resistance to M. fortuitum. This research demonstrates giant gourami can be successfully immunized orally against pathogenic M. fortuitum. [ABSTRACT FROM AUTHOR]

Background and Aim: Coccidian infection (coccidiosis) is one of the most important causes of illness and death in the fish population, including Asian sea bass. The fingerling developmental stage is sensitive to various infectious agents. Economic losses are sustained by the sea bass aquaculture industry due to coccidiosis annually. However, the related pathological changes in the Asian sea bass fingerlings' three-part intestine remain unknown. This study aimed to investigate the Asian sea bass fingerlings' infection rate, infection location and site, and specific pathological lesions in the small intestinal tissues in a marine cage farming operation. Materials and Methods: A cross-sectional study was conducted on 44 fingerling fishes. Major coccidia proportions were identified morphologically at both the macroscopic and microscopic levels. The infection number was determined based on coccidia presence at various intestinal locations and sites. All areas were assessed for pathological lesions using semi-quantitative grading. Analysis of variance was used to perform all data analyses using the SPSS software. Data were expressed as means ± standard deviation. p < 0.05 was considered statistically significant. Results: All Asian sea bass fingerlings studied were infected with coccidia. Enteritis and mucosal necrosis were distinct lesions found in the anterior intestine, which had the highest infection rate (49.94%), followed by the mid intestine (35.63%), and the posterior intestine (22.43%). The most common coccidian infection site was extracellular (subepithelial), followed by intracytoplasmic, and epicellular sites. Histopathological lesion determination revealed that intestinal tissue inflammation and epithelial injuries were predominantly seen in the anterior gut (p < 0.05). Conclusion: There was a high coccidian infection rate in Asian sea bass fingerlings from marine cage farming operations. Infection and intestinal damage at the anterior intestine, a major site, led to fingerling death. Disease prevention in the nursery should be intensive from the fingerling period to decrease the fatality rate caused by coccidia. [ABSTRACT FROM AUTHOR]

The pace of research efforts has been extraordinarily accelerated across the globe to address the contamination issues caused by pesticides, and fertilizers, especially in the aquatic ecosystem. The sole aim of this study was to assess the effect of urea on Nile tilapia (Oreochromis niloticus). For this purpose, the fish fingerlings were exposed to increasing concentrations of urea such as 0, 1, 2.5, 5, 10, 20, and 40 g/l for 72 h. Survival analysis suggested a strong correlation between the increasing doses of urea and the mortality rate among tested fingerlings. This study reported remarkable morphological, and behavioural alternation such as increased operculum movement, bottom-dwelling, lethargy, secretion of mucus, reduction in food intake, and bleeding in the fin and around the mouth in the treated group. Haematological analysis revealed that a significant reduction in RBC count and Hb along with an increase in WBC number is associated with urea toxicity. Our study showed a significant rise in glucose concentration upon urea toxicity in Nile tilapia fingerlings for the first time, emphasizing the adverse effect of fertilizers on carbohydrate metabolism. Significant rises in the enzymatic activity such as alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) upon urea treatment emphasize the possibilities of liver damage, biliary obstruction, and abnormal glucose metabolism. Histological analysis of urea-treated fish compared to normal fish revealed that urea toxicity drastically altered the tissue architecture of fish's gills, eyes, intestine, and stomach. As the visual systems of mammals and fish resemble in more aspects, our findings may be useful in understanding the impact of pollutants on sensory organs concerning humans. We conclude that our findings highlight the importance of urea toxicity on Nile tilapia fingerlings and invite multidisciplinary research to uncover molecular mechanisms underlying urea toxicity. [Display omitted] • Urea toxicity disorganized morphological, and behavioural response of Nile tilapia. • Urea contamination induced histological alteration in gills, intestine, and stomach. • Urea contamination induced disturbance in carbohydrate metabolism. • This study helps to understand the impact of pollutants on sensory organs. [ABSTRACT FROM AUTHOR]

Streptococcosis and columnaris diseases caused by Streptococcus iniae and Flavobacterium covae, respectively, crucially impact Asian seabass aquaculture in Thailand. In this study, we built upon research in which Asian seabass larvae were immersed and orally immunized with a bivalent nanovaccine formulated from S. iniae and F. covae. Control and vaccine-primed fingerling fish (2.38 ± 0.67 g and 5.68 ± 0.53 cm) from two different nursery farms underwent consecutive vaccination trials and were orally booster vaccinated 2 times. The first and second vaccinations were orally administered on days 0 and 15 at the same concentration (1 × 108 CFU/fish) via experimental feed. At 0, 15, and 30 days after the first vaccination (DAFV), tissues from the head kidney, spleen, gills, and intestine were sampled to investigate total IgM, specific IgM to S. iniae and F. covae , innate immune responses, histology, and expression analysis of immune-related genes. The results showed that the nanovaccine strongly increased the total IgM concentration in the head kidney and spleen of vaccinated fish to a significantly greater extent than that in the control group (P < 0.05) for both farms. IgM specific to S. iniae and IgM specific to F. covae , as well as the expression of genes involved in specific immune responses (IgM, IgT, IgD, CD4, MHCIIα , and TCRα) in all target organs, were significantly greater in all vaccinated groups than in the control group (P < 0.05). Histopathological examination revealed greater interbranchial lymphoid tissue (ILT) size, more lymphocyte-like cells in the gills, and increased goblet cell density in the intestines of vaccinated fish than in those of control fish. Furthermore, the fish that received the nanovaccine exhibited a significantly greater cumulative survival rate than those in the control group, regardless of whether the nanovaccine was tested against S. iniae or F. covae. This highlights the effectiveness of the vaccine in stimulating the immune system to provide sufficient disease resistance against both types of diseases in fish. [Display omitted] • Chitosan-bivalent nanovaccine (CBNV) was prepared Streptococcus iniae and Flavobacterium covae isolated from Asian seabass. • CBNV strongly elevated total and specific IgM to S. iniae and F. covae in the 90-days-old CBNV-primed vaccinated fish. • CBNV was effective in elevating expression levels of IgM, IgT, IgD, CD4, MHCIIα , and TCRα genes in vaccinated fish. • CBNV significantly improved histological changes in the intestines and gills of vaccinated fish. • CBNV finally significantly improved disease resistance against both S. iniae and F. covae of vaccinated fish. [ABSTRACT FROM AUTHOR]

Plasma-activated water (PAW) is a useful tool for producing pathogen-free seed fish. This study aimed to apply dielectric barrier discharge (DBD) plasma to reduce the microbial population in the water of a recirculating aquaculture system (RAS) for Nile tilapia larval culture. Initially, a PAW system prototype was developed and found to effectively reduce bacterial populations in both stagnant and circulating water. Additionally, a slight increase in water temperature was observed in the circulating water. Subsequently, the optimisation of PAW conditions in the circulating water was performed. The PAW system, with a copper anode distance of 2 cm and a 1 cm distance between the copper tip and the water surface, combined with a non-spaced cathode pad, exhibited the highest bactericidal effect. Using the optimised PAW conditions, for Experiment I, Nile tilapia larval culture was established in the RAS, supplemented with a bacterial suspension (Bacillus subtilis , Streptococcus agalactiae and Aeromonas hydrophila) to assess the bactericidal effects. Three treatments were applied: 1) control (no PAW or antibiotics), 2) PAW, and 3) antibiotic treatment for Nile tilapia larvae cultured in the RAS system for 672 h. The results demonstrated that both PAW and antibiotic treatments significantly reduced the bacterial populations in the water in relation to the control (P < 0.05). Moreover, a substantial reduction in bacterial population was observed in the whole body of the fingerlings in both the PAW and antibiotic groups in relation to the control fingerlings (P < 0.05). In Experiment II, Nile tilapia larval culture in the RAS was conducted under three different conditions: 1) control (no PAW or antibiotic), 2) PAW, and 3) antibiotic treatment, to evaluate the antimicrobial effects of PAW on waterborne bacterial populations for 672 h. Similar to Experiment I, both antibiotic and plasma treatments significantly reduced the bacterial populations in the water and whole-body fingerlings in relation to the control (P < 0.05). Notably, the growth performance and whole-body composition (moisture, crude protein, crude fat, and ash) of the fingerling fish appeared comparable among the experimental groups (P > 0.05), suggesting that PAW had no detrimental effects on long-term fish culture. Therefore, PAW can be employed to effectively reduce bacterial populations in water, thus minimising bacteria-related issues in fish without adverse impacts on fish growth. • PAW reduces bacterial populations in stagnant and circulating water. • Strongest bactericidal effect in a RAS for Nile tilapia larval culture. • PAW and antibiotic treatments reduce bacteria in water and whole-body fingerlings. • Antimicrobial effects on waterborne bacteria without affecting fish growth. • Plasma technology is a safe, green option for water disinfection in aquaculture. [ABSTRACT FROM AUTHOR]

Deltamethrin (DLM), in combination with the synergist piperonyl butoxide (PBO), is extensively used in pest control programs due to its potent pesticidal properties and appreciable safety margin. However, various research studies report their adverse effects on non-target organisms. In this study, we investigated the toxicity of DLM, PBO, and a DLM-PBO (3:1) combination on Labeo rohita (L. rohita) fish fingerlings. Fish behavior and mortality rates were recorded at different time intervals up to 96 h for concentrations of 0.003, 0.007, 0.015, 0.031, and 0.062 µg/mL, respectively. Biochemical, hematological, and histopathological studies were carried out. High-performance liquid chromatography (HPLC) was used to detect and quantify residues in fish samples. The LC50 values after 48 h for DLM, PBO, and DLM-PBO exposed fish fingerlings were found to be 0.028, 0.066, and 0.007 µg/mL, respectively. At a concentration of 0.003 µg/mL of DLM, PBO, and DLM-PBO, the treated fish fingerlings exhibited similar behavior to the control group. Hematological parameters, such as red blood cell (RBC) and white blood cell (WBC) counts, were reduced in the treated groups compared to the control. Biochemical parameters showed increased levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), while total serum protein levels decreased in DLM, PBO, and DLM-PBO treated fingerlings. Histopathological examination of liver, gill, and heart tissues revealed lesions with hydropic degeneration in the liver and fusions of gill lamellae in the treated tissues. Fish fingerlings exposed to the DLM-PBO combination appeared highly prone to toxicity compared to those treated with DLM and PBO separately. [Display omitted] • Combined DLM-PBO exposure was more toxic to L. rohita fingerlings than single exposures. • Notable tissue damage was observed, including hydropic degeneration and gill lamellae fusion. • Significant behavioral disruptions were evident at higher concentrations. • PBO accumulated more in fish tissues than DLM, highlighting differential bioaccumulation. • Findings suggest potential environmental risks of prolonged DLM use, emphasizing the need for careful management. [ABSTRACT FROM AUTHOR]

Francisella orientalis infections, known as francisellosis, are one of the most important diseases affecting the production of Nile tilapia, causing high mortality rates in the most susceptible fish stages: fingerlings and juveniles. Antibiotic therapy is the method of choice for treating the disease, as there are no commercially available vaccines. In this study, we developed an inactivated whole-cell vaccine using an isolate of F. orientalis in combination with the aqueous adjuvant Montanide IMS 1312 VG, which was administered to Nile tilapia through immersion. Two immunization trials (1 and 2) were conducted with fish at the fingerling and juvenile stages. For each trial, five different experimental groups were established: a complete vaccine (bacterin in combination with aqueous adjuvant), bacterin, aqueous adjuvant, and positive and negative controls. Thirty days after vaccination, an experimental challenge was performed through intraperitoneal injection of the same F. orientalis isolate. As a result, the vaccinated fingerlings were the only group in which mortality and progression of clinical signs of francisellosis were statistically significantly reduced, although relative percentage of survival (RPS) was low at 50%. In the juvenile group, RPS was higher at 63%, but not statistically significant. Nevertheless, an RPS of only 50% is acceptable for using vaccines in the field. The bacterin and adjuvant treatments alone were not effective, showing an RPS of 37% and 0%, respectively. Post-vaccination mortality was observed in the group exposed only to the adjuvant, which may indicate excessive immune stimulation at this stage. Interestingly, the immune response elicited by the vaccine was unable to eliminate the pathogen from the host; therefore, the surviving animals became carriers. Although the immune response elicited by the vaccine was unable to eliminate the pathogen from the host, this vaccine formulation could be a viable alternative for use in the field and serve as another means of controlling the mortality caused by the pathogen. Our study provides the first report of vaccination, using immersion, against francisellosis at the most susceptible stages of farmed Nile tilapia. Future studies should address the efficiency of immersion vaccines under field conditions. • This is the first report of an inactivated whole cell immersion vaccine against francisellosis. • The vaccine was effective to prevent mortality in Nile tilapia juveniles. • The vaccine was partially effective in Nile tilapia fingerlings. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of taurine, an amino acid additive, on grass carp Ctenopharyngodon idella fingerlings (3.16 ± 0.14 gm) growth and feed utilization in glass aquaria for 70 days. Before beginning the feeding experiment, 120 fish were acclimatized for 10days in the laboratories of fisheries department and marine resources, Agriculture College, University of Basrah. Fish fed dietary taurine at levels of 1% (T2), 2% (T3), and 3% (T4) were compared to fish fed a control diet with no taurine (0%, T1). The weight gain (WG) in the T1 was 16.95 g, which was significantly (P≤0.05) higher than the other treatments. T1 had a higher (P≤0.05) mean relative growth rate (RGR) (54.89± 5.66 %) than the other treatments. The specific growth rate (SGR) and daily growth rate (DGR) of T1 were 0.72 ± 0.06 % day-1, and 0.28 ±0.01 g, which was also higher (P<0.05) than other treatments supported with different levels of taurine. Significant differences (P≤0.05) were found in the food conversion ratio (FCR) and food conversion efficiency (FCE) between T1 and the other treatments (T2, T3, and T4). It is clear from the current study that the T1 (0% taurine) better than the other treatments in growth and food utilization indicators. It is concluded from the current study that the addition of taurine (1, 2 and 3%) had inhibited the growth in grass carp fingerlings. [ABSTRACT FROM AUTHOR]

The present study was carried out in FRP pools (1.5 × 1.0 × 0.75 m) for the period of 120 days to evaluate the possibility of dietary incorporation of kinnow peel powder (KPP) as feed additive in supplementary feed of common carp (Cyprinus carpio L.) fingerlings. Healthy fingerlings of common carp were equally distributed (@15 nos. /pool) in five feeding treatments having three replicates each. Five iso-proteinous experimental feeds, containing KPP at 0 (KPP0), 0.5 (KPP1), 1.0 (KPP2), 1.50 (KPP3) and 2.0% (KPP4) inclusion levels were fed to fingerlings at 2% of fish body weight. The overall result revealed that all the water quality parameters stayed well within the optimum range throughout the experimental period in all the treatments, which showed that addition of KPP in fish feed has no adverse effect on water quality. Fish survival % ranged between 88.89 to 93.33% in KPP fed treatments (KPP1-KPP4) as compared to 88.89% in control (KPP0). Growth performance, with respect to net weight gain (NWG) and specific growth rate (SGR) of fish was significantly improved (P≤0.05) in all the KPP fed treatments, being highest (22.0 g and 0.93%, respectively) at 1.5% inclusion level (KPP3) and lowest in control (15.97g and 0.78%, respectively). Inclusion of KPP in fish feed also improved the feed utilization efficiency (FCR and PER) and among all the treatments, best (P≤0.05) feed utilization efficiency (FCR 1.94 and PER 1.96) was recorded in 1.5% KPP fed treatment as compared to control (FCR 2.37 and PER 1.58). Inclusion of KPP in fish feed also improved the flesh quality of fish. The total protein content (wet weight basis) in fish flesh was significant (P≤0.05) higher in all the KPP fed treatments and depicted maximum enhancement (16.25%) at 1.5% inclusion level (KPP3) as compared to control. The overall results revealed that dietary inclusion of KPP @ 1.5% in the fish feed can enhance growth performance, feed utilization efficiency and flesh quality of common carp. [ABSTRACT FROM AUTHOR]

Biofloc technology is considered as a culture system for fish production reduced environmental impacts. In the present study investigated the impact of zeolite nanoparticle on water quality, growth performance, digestive enzymes and immune response of common carp (Cyprinus carpio) reared under biofloc conditions. Fish fingerlings (initial weight of 7.99 ± 0.36 g) were divided into four treatments and fed four levels of zeolite nanoparticles in the following 0 (control), 50, 100 and 200  mg kg−1 diet in biofloc system (NZ1, NZ2 and NZ3) for 60 days. Carbon to nitrogen ratio (15:1) was provided using sucrose. Water quality parameters such as nitrogen compounds were measured during the test period. At the end of the experiment, the highest growth indices and the lowest feed conversion ratio were obtained in 50 mg kg−1 diet (NZ1). Intestinal protease activities in NZ1 and NZ2 treatments were significantly higher than in the other treatments, and the highest lipase and amylase activity was related to the NZ1 treatment. The 50 and 100 Zeolite diets in biofloc conditions significantly enhanced fish immune system activity. The present study suggests that dietary supplementation with 50 and 100 mg Zeolite nanoparticles in biofloc system significantly increases growth performance, digestive enzyme, and immunological response in common carp in fish culture tanks. [ABSTRACT FROM AUTHOR]

The present study was designed to evaluate the effect of soluble polysaccharides in Spirulina platensis microalgae on growth performance, body composition and immune response of rainbow trout (Oncorhynchus mykiss). In this regard, 180 rainbow trout (17.22 ± 0.5g) were selected and distributed in five experimental treatments (with three replications). Treatments included different levels of polysaccharide in dosage of 0 (control), 500, 1000, 2000 and 3000 mg / kg of feed distributed in 15 fiber glass tanks (100 liters). Fish fingerlings were fed three times a day by satiation for 8 weeks. According to the results, in growth indices (final weight, body weight gain, specific growth factor, protein efficiency, feed conversion ratio and condition factor), no significant difference was observed among the treatments, However, the slight improvement was observed at 500 mg polysaccharide / kg diet. The survival was high in all treatments without any significant difference. Regarding the chemical composition of the body, the highest and the lowest amount of carcass proteins were observed in the diet containing 500 mg polysaccharide and control, which showed a significant difference. No significant difference was observed in the amount of ash, moisture and fat in treatments (P <0.05). The amount of fatty acids of the muscle of the fish body did not show any significant difference among the treatments. The amount of SFA in the control treatment was higher than other treatments. MUFA in 500 mg treatment, PUFA in the treatment of 2000 mg and HUFA and n3 / n6 levels in the treatment of 3000 mg polysaccharides per kg of diet were highest. The level of lysozyme and alternative complement activity of serum was significantly different in different treatments (P <0.05), so that the highest and lowest levels of lysozyme activity were observed in treatments of 2,000 mg polysaccharide and control and the highest and lowest levels of complement activity were observed in treatments containing 3000 mg polysaccharide and control respectively (P <0.05). In general, the use of polysaccharide extracted from micro-algae did not significantly improve rainbow trout growth, but a slight improvement in growth and body composition (protein) in 500 mg polysaccharide per kg of diet was observed. In terms of safety indicators, treatments of 2,000 and 3,000 mg of polysaccharides per kg of diet had a good performance and could be used whenever needed. [ABSTRACT FROM AUTHOR]

Stocking density of fish is species specific and is considered as one of the crucial aspects for optimizing feed and water-quality management in biofloc system. The present study was carried out to determine the optimum stocking density of a prime aquaculture species, climbing perch Anabastestudineus in biofloc system. Fish fingerlings with a mean initial weight of 0.80 ± 0.02 g were reared in biofloc tanks for 13 weeks under three different stocking densities, 300 (T-300), 450 (T-450), and 600 (T-600) fish m−3 in triplicates, and the fish were fed with a commercial diet at 3% of their body weight. At final harvest, significant differences in growth and body composition were observed among the treatments. T-300 and T-450 showed similar growth pattern (p > 0.05), while fish in T-600 registered significantly poor growth (p < 0.05). The fitted models for all the growth variables were quadratic, and daily individual feed intake was linear. Although the regression model for yield was not significant (p = 0.072), the highest yield (kg m−3) was attained in T-450. Dry matter, protein, and lipid content of fish remained unaffected (p > 0.05), while significant (p < 0.05) difference in ash content was observed among the treatments with the highest being found in fish from T-600. These results suggest that at the initial stage of culture the optimum stocking density of climbing perch in biofloc system is 300–450 fish m−3 although higher stocking might be feasible considering periodic water exchange and solid management, a proposition awaits further elucidation. [ABSTRACT FROM AUTHOR]

This research is done to reveal the effect of water flow on the round container to increase the growth and survival rate in bonylip barb. The method used in this research is an experimental method using a Completely Random Design (CRD) which is consist of three treatments and five repetitions. The treatments are round container without water flow (A), round container with 0,1 m s-1 of water flow (B) and round container with 0,1 m s-1 of water flow with an additional venturi aerator. The numbers of bonylip barb fingerlings used in this research are 900 with a length of 1-3 cm. The container used in this research is 15 water gallons with a volume of 19L. The density of the container is 60 fish per container. Fish maintained for 40 days. The feeding rate given is 5% of the biomass. The observed parameters are survival rate, daily growth rate and feed conversion ratio observed every 10 days. The result showed that the water flow combined with the venturi aerator give the best result with 77.3% of survival rate, 3.12% of daily growth rate and 1.42 feed conversion ratio. [ABSTRACT FROM AUTHOR]

Background: Stunting is a process of suppressing growth from unfavourable conditions. The protein supplementation during stunting gives scope to maintain the nutrient reserves of fish and its quality. Methods: A feeding trial was conducted for eight months to study the effect of three hetero-nitrogenous diets with 25% (control), 30% (T1) and 35% (T2) crude protein (CP) levels on growth and physio-metabolic responses of Chanos chanos fingerlings during stunting. Milk fish fingerlings with a mean body weight of 11.71±0.18 g were stocked in earthen ponds @ 20 no/m2 in each replicate (n=3) was fed @ 2% biomass throughout the experiment. Result: Fish fed with T1 diet showed better specific growth rate (0.64±0.01% d-1), weight gain percentage (362.56±14.95) and protease activity (7.53±0.25 U/mg protein). Whereas, lower activity was observed for the enzyme assay, namely superoxide dismutase (45.41±2.50 U/min/mg protein), aspartate aminotransferase (34.01±1.88 U/min/mg protein) and alanine aminotransferase (39.64±0.64 U/min/mg protein). Hence, it may be concluded that the dietary protein inclusion level of 30% CP showed better growth performance and lower physio-metabolic response in milkfish fingerlings during the stunting. [ABSTRACT FROM AUTHOR]

Immobilized microalgae are a promising approach to incorporate microalgae in recirculating aquaculture system (RAS) for water purification. In the present study, two types of biosorbents including sodium alginate–immobilized Scenedesmus spp. and Chlorella spp. beads (algal beads) and sodium alginate beads without microalgae (alginate beads) were prepared. In the first experiment (static test), the potential of two biosorbents to remove different concentrations of total ammonia nitrogen (TAN) and total phosphorus (TP) from water was investigated. In the second experiment, two prepared biosorbents were used as biofilter in a RAS for rearing African cichlid (Labidochromis lividus) for 30 days. The survival rate and growth indices of fingerling fish and removal efficiency of two biosorbents for TAN, NO3—N, and TP were determined. The results of static test showed that the removal efficiency and uptake capacity of the two biosorbents for TAN and TP increased during 30 days of the experiment, and these values for the algal beads were higher than the alginate beads. The TAN removal efficiency of the two biosorbents increased with increasing TAN concentration from 0.5 to 5 mg L−1. The application of algal beads in the RAS improved the survival rate, final weight, final length, weight gain, and daily growth index (DGI%) indices of fish compared to those cultured in the RAS containing the alginate beads and the control (P<0.05). The algal and alginate beads decreased the TAN concentration by 42.85% and 28.57% compared to the control after 30 days of cultivation period, respectively. The uptake of nitrate was not observed by the two biosorbents during cultivation period. The TP removal efficiency of algal beads reached 44.90% after 30 days. The findings of this study indicated that the sodium alginate–immobilized microalgae could be considered as a suitable biofilter to be incorporated into a RAS to improve water quality and consequently enhance the growth and health of fish. [ABSTRACT FROM AUTHOR]

Nursery rearing is the critical interim phase in farming of Asian seabass fish (Lates calcarifer), which produce fish fingerlings as an input for grow-out farming. The present study evaluated the techno-economic performance of seabass nursery rearing in low and high saline coastal waters. The results indicated that seabass nursery rearing is technically efficient with a mean technical efficiency of 99.83% and 92.45%, respectively under low and high saline conditions. The mean survival of young fishes was 63.50% and 42.50% with a mean daily weight gain of 0.08 g and 0.15 g, respectively in low and high saline waters. While the benefit cost ratio (BCR) was 2.76 and 1.9, the internal rate of return (IRR) was calculated to be 300% and 130%, respectively, indicating the economic viability of nursery rearing under different salinity regimes. Furthermore, it was observed that nursery rearing in low saline waters was more efficient and highly remunerative. In the Indian socio-economic scenario, a mean monthly income per person spending 2 h per day was found to be 129 USD and 317 USD respectively in high and low saline nursery systems which is a considerable earning. The results explicitly stated that nursery rearing itself is an exclusively livelihood development activity for the coastal fisher families with an active participation of fisher women. Establishment of finfish hatcheries to ensure continued supply of seabass seeds is the key factor in facilitating wider adoption of nursery rearing as a sustainable farming activity. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the effects of dietary non-encapsulated and microencapsulated Lactobacillus delbrueckii subsp. bulgaricus on growth performance, intestinal enzymatic activities, antioxidant capacity and hepato-biochemical parameters of rainbow trout before or after exposure to lead via diet. Fingerling fish (16 ± 4 g) were divided into four groups: negative control (NC), positive control (PC), probiotic (PR) and encapsulated probiotic (EN-PR). During the pre-exposure period (days 0–45), fish in the NC and PC groups received the basal diet, whereas fish in the PR and EN-PR groups were fed with basal diet containing 108 CFU g−1 feed of non-encapsulated and microencapsulated probiotic, respectively. During the exposure period (days 46–66), the fish in the probiotic and PC groups were co-treated with 500 μg g−1 feed of lead nitrate. Blood, liver and gut samples were taken at days 0, 45, 52, 59 and 66. The results revealed that growth performance and intestinal enzymatic activities were significantly (P<0.05) improved in the probiotic groups compared to the NC group (day 45). Dietary exposure to lead resulted in the highest levels of liver aspartate aminotransferase (AST), liver alkaline phosphatase (ALP) and serum malondialdehyde (MDA), and the lowest activities of serum superoxide dismutase (SOD) and catalase (CAT) in the PC group (day 66). The levels of liver ALP were significantly (P<0.05) lower in the probiotic groups compared to the NC and PC groups prior to and after exposure to dietary lead. Serum levels of total protein, albumin, SOD, CAT and glutathione (GSH) were significantly increased in fish fed with both non-encapsulated and microencapsulated probiotics (P<0.05). However, microencapsulated probiotic showed the greatest potential for alleviation of the disturbed activities of intestinal and hepatic enzymes, and improvement of serum biochemical and antioxidant parameters. Our findings suggest that L. delbrueckii subsp. bulgaricus, particularly in the microencapsulated form, can be used as a potential probiotic to protect rainbow trout from dietborne lead toxicity. [ABSTRACT FROM AUTHOR]

The study was carried out for three (3) months to determine the influence of a commercial probiotic Antox® which is a mono-strain probiotic consisting of live Saccharomyces cerevisiae at 4.125 × 106 cfu per 100ml on growth, nutrient utilization and body composition of Clarias gariepinus fingerlings. Fish fingerlings (7.6 - 7.9g) were randomly distributed into five triplicate treatment groups in fifteen plastic tanks (80L) at a stocking density of ten (10) fish per tank. The probiotic was administered in the culture water of the treatment groups; 0mls (control, T0), 0,5ml (T1), 1.0 (T2), 1.5 (T3), 2.0 (T4) ml probiotic/80l. Water quality parameters were regularly monitored. The growth performance, nutrients utilization and body composition of C. gariepinus fingerlings between probiotic treated groups were significantly increased (P < 0.05) with increasing dosage of the probiotic. The best Final Mean Weight (121.3g), Mean Weight Gain (113.5g), Percentage Mean Weight Gain (1456.5g), Feed Conversion Ratio (0.92g) and Protein Efficiency Ratio (2.6g), were recorded in probiotic treatment group T4 (2.0ml). Similarly, the highest increase in carcass crude protein (69.9g), moisture (10.34), ash (15.26g) and dry matter (29.46) were recorded in treatment group T4 (2.0ml). Probiotic (Antox®) is recommended for administration in C. gariepinus fingerlings culture water at 2.0mls/80L. [ABSTRACT FROM AUTHOR]

The aim of the present research is to study the efficacy of rosemary oil as an anesthetic for bighead carp (Hypophthalmichthys nobilis Richardson, 1845) and as an anesthetic used for transport of fingerlings. The fish used in the experiment have an average body weight (BW, g) of 42.13±17.90 and an average total length (TL, cm) of 16.54±2.32. Five treatments are conducted with five experimental concentrations: 0.20 ml.l-1, 0.30 ml.l-1, 0.40 ml.l-1, 0.50 ml.l-1 and 0.60 ml.l-1. For each concentration 10 fish are used or a total of 50 fish. For the transport experiment, 3 concentrations are used: 0.06 ml.l-1, 0.08 ml.l-1 and 0.10 ml.l-1. The applied stocking density is 3 fish/l. A total of 60 fish are used for each concentration or a total of 180 fish. The established results, for the first experiment, show that at concentration of 0.60 ml.l-1 the induction of anesthesia is the fastest (3.46 min). From all tested concentrations the recovery time is the shortest at the lowest concentration - 2.16 min (p≤0.001). The concentration of 0.10 ml.l-1 of rosemary oil can be used for transport of bighead carp fingerlings for a period from 1 to 2 hours. The concentration of 0.08 ml.l-1 can be applied when the duration of the transport is from 1 to 3 hours. [ABSTRACT FROM AUTHOR]