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The present study investigated the effects of short-chain fructooligosaccharides (FOS) as dietary supplements on stress, immune response, gut microbiota, growth, and survivability of three different treatment groups of Pacific white shrimp, Litopaneous vennamei, cultured in a recirculating system. The experiment was conducted over a 35-day trial period. Shrimps were fed diets, 15 times a day using automated feeder, supplemented with GOS at 0%, 0.15%, and 0.30% by weight. Denaturing gradient gel electrophoresis analysis revealed that the enteric microbial community of shrimp fed the basal diet differed markedly (<80.0% similarity coefficient) from those fed FOS-supplemented diets. However, shrimp survival, weight gain, and immune responses among the treatment groups were good but not significantly different (P > 0.05), probably due to the limited length of the feeding trial. [ABSTRACT FROM AUTHOR]

This study was designed to examine the effects of a prebiotic compound on the immune system, digestive tract histology, and stress physiology of shrimp. The specific effects of dietary supplementation of the prebiotic galactooligosaccharide (GOS or GTGOS) on shrimp health are scarce. This experiment, therefore attempted to evaluate the effects of GOS on growth, survival, intestinal microbiota, stress resistance and immune responses of Pacific white shrimp, Litopaneous vannamei. Over a 35-day trial, shrimps were fed diets, 15 times a day using automated feeder, supplemented with GOS at 0%, 0.25%, and 0.40% by weight. Shrimp survival and weight gain among the treatment groups were good but not significantly different (P >.05). Shrimp fed GOS-supplemented diets had reduced stress (glucose, P <.05) and increased immune responses (total hemocyte counts and phagocytic capacity, P <.05) compared to shrimps fed only basal diet with no supplementation. These results suggest that GOS not only changed the populations of gut microbiota but also reduced stress levels and enhanced immune response in shrimp. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to characterize the pantothenic acid deficiency signs and quantify the dietary requirement of juvenile hybrid striped bass, Morone chrysops × Morone saxatilis . A basal diet composed of fish muscle and crystalline amino acids was analyzed to contain 5 mg of pantothenate/kg and supplemented with calcium d -pantothenate resulting in five diets with graded pantothenate levels of 5, 10, 20, 30 and 40 mg/kg diet. Each diet was fed to triplicate groups of hybrid striped bass juveniles (initial average weight 1.6 g) in a recirculating system at 26.0 ± 1 °C. Fish fed the unsupplemented basal diet performed poorly in terms of growth parameters and exhibited typical signs of pantothenic acid deficiency such as hemorrhages, sluggishness, high mortality, anemia and severe hyperplasia of the epithelial cells of gill lamellae. Fish fed the diet containing 10 mg of pantothenate/kg diet performed significantly better than fish fed the basal diet but poorly when compared with the responses of fish fed diets containing 20, 30 and 40 mg of calcium d -pantothenate/kg diet. Also, pantothenic acid-deficiency signs were apparent in fish fed the diet containing 10 mg/kg diet; whereas, no deficiency signs were observed in fish fed diets supplemented with the higher levels. Based on these data, the dietary pantothenic acid requirement of hybrid striped bass was quantified at 18.8 mg/kg diet based on broken-line regression analysis of weight gain data. Statement of relevance Pantothenic acid deficiency in hybrid striped bass was characterized and the minimum dietary pantothenic acid requirement was determined to be 18.8 mg/kg based on weight gain. This information will assist in refining diet formulations for hybrid striped bass. [ABSTRACT FROM AUTHOR]

A study was undertaken to examine the potential of two non-genetically modified (non-GM) soy products, differentially processed, as fishmeal (FM) replacements. Dietary protein (DP) was replaced at 50, 60 and 70% using the 3011 meal or 40, 50 and 60% with the 3032 meal. Ingredient 3011 was a cooked and solvent-extracted meal from a high protein and low oligosaccharide soy cultivar; whereas, ingredient 3032 was a cold-pressed, low fat cake ground to a meal that originated from a medium protein, low oligosaccharide, low protease inhibitor soy cultivar. Experimental diets were isonitrogenous (45% crude protein, CP), isolipidic (13% lipid), isocaloric (12.6 kJ energy kg − 1 of diet) and were balanced for lysine (3.2%) and methionine + cysteine (2%). Taurine was supplemented at 1.5% in all diets. A commercial control diet (52% CP and 13% lipid) was included for a total of eight test diets. Twenty four round tanks (330 L) were each stocked with 20, 4 g yellowtail ( Seriola lalandi ). Tanks were supplied with recirculated seawater and each diet was randomly assigned to three replicate tanks. After a 10-week feeding trial, growth, survival, feed conversion ratio, protein efficiency ratio, protein retention, condition factor and carcass proximate composition were contrasted among dietary treatments. Results indicate that juvenile yellowtail fed diets in which the 3032 meal provided 50 and 60% of DP grew significantly ( P < 0.001) better than those fed all other diets, including the FM-based (menhaden FM) and commercial control diets. Fish fed with the 3011 meal providing 50% of DP and those fed with the 3032 meal providing 40% of DP had similar growth performance which was slightly greater than the fish fed the FM reference diet. Minor intestinal histology differences were found among fish fed the 8 diets. Taken together these data indicates that the improved non-GM soybean meals supported better performance of juvenile yellowtail than fish fed the FM reference diet. No enteritis was detected even at high dietary inclusion levels. [ABSTRACT FROM AUTHOR]

Fishmeal (FM) replacement in diets for intensive aquaculture has become a high priority area for the global aquaculture industry. In this study, a twelve week growth trial was conducted with juvenile cobia (18 g initial weight) to examine the effects of non-genetically modified soybean meals as potential replacement protein sources. Genetically modified (GM) crops and their intended and unintended effects have become major topics of controversy worldwide, with several regions banning their use in food and feeds. Therefore, it is especially critical to develop and evaluate non-GM feedstuffs for use in aquaculture diets where GM products are prohibited as the global aquaculture industry continues its expansion to meet increasing demands. Navita Premium Feed Ingredients (NPFI's) 3010 solvent extracted meal and 3032 cold-pressed cake meal were utilized to replace 50, 60 or 70% and 40, 50, or 60% of FM protein, respectively and were compared to a FM based reference formulation. None of the experimental diets performed significantly different from the reference diet in terms of weight gain (WG) or specific growth rate (SGR). However the 3010 50% diet performed significantly better than the 3032 50 and 60% diets in regard to WG, SGR, and protein efficiency. There were no significant differences between the seven diets at the conclusion of the trial in regard to their effects on filet quality as determined by organoleptic testing. These two non-GM soybean protein sources appear to be valuable FM replacement options for juvenile cobia, with none of the typical indicators of intestinal enteritis developing as has been observed in various other teleost species when high quantities of commodity soybean meal have been utilized. [ABSTRACT FROM AUTHOR]

Juvenile channel catfish Ictalurus punctatus were fed casein-gelatin-based semi-purified test diets with graded amounts of arginine ( ARG, 0.5%, 1%, 2% and 4% of dry diet) for a 6-week period, to evaluate the effects of dietary ARG supplementation on performance indicators, levels of plasma ARG, ornithine, citrulline, glutamine and glutamate, as well as selected innate immune parameters. Incremental dietary ARG resulted in significant improvements in weight gain, feed efficiency and protein efficiency ratios, protein retention, protein deposition and arginine deposition. Fish fed the 4% ARG diet had significantly higher values for all performance indicators, although these values were not different from those of fish fed the 2% ARG diet with the exception of protein retention, protein deposition and arginine deposition. Conversely, fish fed the 0.5% ARG diet had significantly lower values for all analysed plasma amino acids. Similarly, both phagocyte superoxide anion production and neutrophil respiratory burst were significantly decreased in fish fed the 0.5% ARG diet. These results demonstrate that the indispensability of dietary ARG is not only related to optimized protein utilization for growth but also its supplementation to fish diets may significantly impact several aspects of the immune system, including phagocyte function and thus improve overall fish health. [ABSTRACT FROM AUTHOR]

Abstract: Thyroid (TH) and growth (GH) hormones, and insulin-like growth factor I (IGF-I) are anabolic regulators in fish and responsive to nutrient intake. A study was conducted to determine if previously reported growth effects of dietary arginine (ARG) in channel catfish were related to the activation of endocrine axes. In a first experiment, catfish were fed incremental levels of ARG (0.5 – 4% of diet) for 6weeks and sampled at 2-week intervals. In a second experiment, fasted (48h) fish were fed a single ration of ARG (0.5 or 4% of diet) and sampled at various intervals (0 to 72h postprandial, PP). Experiment 1 did not reveal any influence of ARG on circulating TH, GH, or IGF-I despite the significantly increased growth of fish fed ARG-enriched diets. In experiment 2, feeding the 4% ARG diet significantly increased the amplitude of pulsatile plasma GH levels and also significantly increased IGF-I mRNA in liver and muscle, (at 2h PP) and plasma IGF-I levels (at 6h PP). Although relatively infrequent sampling failed to reveal alterations in TH or GH levels in response to ARG-induced growth activation, PP high frequency sampling unveiled high amplitude pulsatile GH secretions and may be important in activating IGF production in target tissues. Additionally, expressed and secreted IGF-I exhibited discernible patterns which closely correlate with ARG-induced growth effects in catfish. [Copyright &y& Elsevier]

Abstract: The present experiment was conducted to investigate the effects of graded amounts of dietary GLN on the intestinal morphology, plasma amino acids and growth performance of juvenile channel catfish. Six experimental diets (280gkg−1 crude protein, 80gkg−1 lipid) were composed of casein, gelatin and crystalline amino acids and supplemented with 0, 5, 10, 15, 20 or 30g free glutamine kg−1. These diets were fed to triplicate groups of fish (average initial weight of 6.1) for 10weeks after which blood and intestinal samples were collected. Intestinal microstructures were positively affected by dietary GLN at the highest levels of supplementation (20 and 30gkg−1), significantly (P <0.05) increasing enterocyte and microvilli height in anterior, mid and posterior intestinal sections. Moreover, a subsequent experiment revealed that GLN supplementation significantly (P <0.05) increased the enterocyte migration rate in all sampled intestinal segments. In contrast, immunohistochemical staining of proliferating cells with mouse anti-proliferating cell nuclear antigen (PCNA), revealed an increased number of proliferating cells only at the distal intestine. Plasma amino acid levels 15h postprandial showed significantly (P <0.05) higher levels of asparagine, serine, glycine and threonine in fish fed the diet supplemented with 20g GLN kg−1 diet. Despite the consistent trend of higher values seen in fish fed the diet supplemented with 20g GLN kg−1, there were no significant (P >0.05) differences in growth-related parameters among treatments. The present results demonstrate an efficient utilization of free GLN by intestinal mucosal cells of channel catfish, which resulted in enhancement of the enteric microstructure along with increased migration rates of enterocytes and modified plasma amino acid profiles. However, these results were not translated into improved growth at the end of the 10-week feeding trial. [Copyright &y& Elsevier]

Abstract: Channel catfish was used to investigate the enhancement of vaccine efficacy following dietary supplementation with arginine (ARG, 4% of diet), glutamine (GLN, 2% of diet), or a combination of both. After vaccination against Edwardsiella ictaluri, humoral and cellular immune responses, along with lymphoid organ responses were evaluated. E. ictaluri-specific antibody titers in plasma were higher (P < 0.05) in fish fed the supplemented diets compared to those fed the basal diet as early as 7 d post-vaccination (dpv). B-cell proportion in head-kidney was higher (P < 0.05) at 14 dpv in vaccinated fish fed the GLN diet. The responsiveness of spleen and head-kidney lymphocytes against E. ictaluri was enhanced (P < 0.05) by dietary supplementation of ARG or GLN at 14 dpv. Additionally, at 7 dpv, vaccinated fish fed the GLN diet had higher (P < 0.05) head kidney weights relative to the other dietary treatments, and vaccinated fish fed ARG-supplemented diets had higher (P < 0.05) protein content in this tissue. Results from this study suggest that dietary supplementation of ARG and GLN may improve specific cellular and humoral mechanisms, enhancing the acquired immunity in vaccinated channel catfish. [Copyright &y& Elsevier]

Abstract: Specific components of both the innate and adaptive immune systems of channel catfish were evaluated after supplementation of culture media with arginine (ARG) and/or glutamine (GLN). Primary cell cultures of head-kidney macrophages (MØ) were used for phagocytic and bactericidal assays against Edwardsiella ictaluri. Additionally, proliferation assays were conducted with naïve peripheral blood lymphocytes (PBL) exposed to non-specific mitogens. To indirectly assess amino acid utilization of both MØ and PBL, amino acid levels, with emphasis on ARG and GLN, were evaluated in the basal medium before and after activation or mitogenic exposure. After bactericidal and proliferation assays, the sum of the media free amino acid pool significantly (P < 0.05) decreased 23% and 45%, respectively. Glutamine levels in medium decreased by 38% and ARG by 18% during the bactericidal assay. Also, decreases of 52 and 46% from initial values were found after the proliferation assay for GLN and ARG, respectively. Macrophage phagocytosis and killing ability was significantly (P < 0.05) enhanced by ARG supplementation to culture media regardless of GLN supplementation. Proliferation of naïve T- and B-lymphocytes upon mitogenic exposure was significantly (P < 0.05) enhanced by supplementing ARG and GLN to the media, but limited synergistic effects were observed. These results suggest that in vitro, ARG and GLN are important substrates and immunomodulators of both innate and adaptive responses in fish leukocytes, and further highlights the potential use of ARG and GLN as immunonutrients in aquafeeds. [Copyright &y& Elsevier]

Abstract: Both arginine and glutamine play important roles in tissue repair, cell replication and collagen synthesis which impact animal growth and survival. Thus, a 7-week feeding trial was conducted to determine the effects of dietary arginine and glutamine on growth performance, innate immune responses and intestinal structure of juvenile red drum, Sciaenops ocellatus (6.9±0.04g, initial average weight). Protein in all experimental diets was derived from menhaden fishmeal and dehulled, solvent-extracted soybean meal to provide isonitrogenous (44% crude protein) and isolipidic (10%) diets. The basal diet contained 0.14% glutamine and 1.72% arginine on a dry-matter basis, which exceeds the established dietary requirement of red drum. Experimental diets were prepared by supplementing the basal diet with either arginine at 1% of dry weight, glutamine at 1%, glutamine at 2%, or both arginine and glutamine at 1%, with adjustments in glycine to maintain equal nitrogen among all diets. Feed efficiency was significantly (P <0.05) improved by supplementation of glutamine at 2% and the combination of both arginine and glutamine at 1% of diet. Neutrophil oxidative radical production in fish fed the glutamine and/or arginine-supplemented diets was significantly (P =0.03) higher compared with that of fish fed the basal diet, with a synergistic effect observed in fish fed the combined arginine–glutamine diet. Significantly (P <0.05) higher serum lysozyme activity also was observed in fish fed the diet supplemented with 1% of both arginine and glutamine. Extracellular superoxide anion production by red drum macrophages was significantly (P <0.05) higher for fish fed diets with glutamine at either 1 or 2% and the 1% arginine–glutamine combination compared to fish fed the basal diet. Similarly, macrophages from fish fed the diet with glutamine at 2% and the arginine–glutamine combination at 1% produced significantly higher amounts of intracellular superoxide anion. Morphometric analyses – i.e., measurements of enterocyte, microvillus and fold heights – demonstrated positive effects of both dietary glutamine and arginine in different portions (proximal, mid and distal) of the gastrointestinal tract of red drum. In general, fish fed the diet supplemented with 2% glutamine had the greatest increases in magnitude of the chosen structures, although those fed the diet with arginine at 1% also yielded improved scores for some enteric portions. Therefore, results from the present study establish the importance of both dietary arginine and glutamine supplementation in improving feed efficiency, as well as eliciting positive changes to several components of the innate immune system and intestinal functionality of red drum. [Copyright &y& Elsevier]

Abstract: Dietary nucleotides have been shown to benefit many physiological and nutritional functions in higher vertebrates and fish. Therefore, a 6-week feeding trial was conducted to evaluate the effects of graded levels of a commercial nucleotide product on growth performance, immune responses and intestinal morphology of juvenile red drum (initial average weight of 7.1g). The basal diet was formulated to contain 40% protein, 10% lipid and a digestible energy level of 3.5kcalg−1. Two levels of nucleotide (Ascogen P®, 0.5% and 1% of diet) were added to the basal diet with menhaden fishmeal and menhaden oil adjusted to provide isonitrogenous and isolipidic diets. Nucleotide supplementation tended to improve weight gain and survival of red drum, but not at a significant level. Neutrophil oxidative radical anion production and serum lysozyme activity tended to be higher for fish fed diets supplemented with nucleotide, while extracellular superoxide anion production of head kidney macrophages from fish fed diets with 1% nucleotide was significantly (P <0.05) increased, although no significant differences were observed between fish fed 0.5% nucleotide diet and the basal diet. Nucleotide supplementation significantly (P <0.05) increased fold height in the proximal intestine, and enterocyte height in the pyloric caeca, proximal and distal enteric sections. A significantly (P <0.05) higher microvilli height was observed in all evaluated enteric sections of fish fed with diets supplemented with nucleotides. It is therefore possible to use dietary nucleotides supplementation to significantly enhance the intestinal structure of red drum. Likewise, nucleotides in the diet may improve some components of the non-specific immune response of this sciaenid fish. [ABSTRACT FROM AUTHOR]

Twelve ingredients obtained from new, non-genetically modified soybean cultivars as well as commercially available sources of soybean meal (SBM) were evaluated in practical feed formulations for the Pacific white shrimp, Litopenaeus vannamei , using both digestibility and growth trials. Apparent digestibility coefficients for energy (ADE) and protein (ADP) were determined using chromic oxide as inert marker and the 70:30 replacement technique. Digestibility coefficients for ADE and ADP ranged from 76.6 to 91.3% and 93.6 to 99.8%, respectively. In general, two distinct groups of high and moderate digestibility values were observed. A separate 8-week growth trial was conducted to evaluate selected SBMs using six replicate tanks per dietary treatment (10 shrimp per tank, initial weight 0.52 ± 0.04 g). An SBM-based reference diet was formulated using commercial SBM (45.3), which was then completely replaced on iso-nitrogenous basis with other experimental SBMs. Significant differences ( P ≤ 0.05) were observed in growth performance but not survival. In general, trends in digestibility values were similar to those of the growth trial. Ingredients (I)-16, I-17, I-18, and I-19 demonstrate relatively higher values in terms of digestibility as well as supporting good growth. Results indicate that genetic selection of soybean for nutritional characteristics of the meal has the potential to increase the nutritional values of SBM for shrimp feeds. Statement of relevance This study provides useful and important information of 12 varieties soybean meal in shrimp to support the aquaculture feed industry development. [ABSTRACT FROM AUTHOR]

Abstract: Various studies with fish species indicate that dietary arginine (Arg) and glutamine (Gln) supplementation may support an enhanced performance beyond simply improving weight gain. Therefore, a feeding trial was conducted to determine the effects of dietary Arg or Gln on growth performance, immune responses and intestinal morphology of juvenile hybrid striped bass, Morone chrysops × Morone saxatilis (4.1±0.02g, initial average weight). The basal diet was formulated from menhaden fishmeal and solvent-extracted soybean meal to contain 45% crude protein and 10% lipid. Arginine and Gln were singularly added to the basal diet at either 1% or 2% or both amino acids were added in combination at 1% to formulate experimental diets with adjustments in glycine to maintain all diets iso-nitrogenous. Fish were fed the experimental diets for a period of 8weeks, at the end of which final weight, specific growth rate and feed efficiency were significantly (P <0.05) higher in fish fed diets supplemented with Arg at either 1 or 2%, Gln at 1%, Arg and Gln both at 1%, but not in those fed the diet supplemented with Gln at 2%. Arginine and/or Gln supplementation tended to improve neutrophil oxidative radical production, but not significantly (P >0.05). However, significantly higher serum lysozyme activity was observed in fish fed the diet supplemented with Arg at either 1 or 2% and Gln at 1%. Intracellular superoxide anion production by hybrid striped bass macrophages also tended to increase, while extracellular superoxide anion production was significantly improved by supplementation of Arg at 1% and Gln at either 1 or 2% of diet. Morphometric analyses demonstrated positive effects of both dietary Arg and Gln on histo-morphological measurements in different portions of the gastrointestinal tract of hybrid striped bass. The 1% Arg diet resulted in the greatest increases in size of the chosen enteric structures, but the other four experimental diets also significantly improved the scores for various intestinal portions compared to fish fed the basal diet. Results from the present experiment demonstrate the importance of dietary supplementation of both Arg and Gln in improving growth performance, eliciting positive changes to several components of the innate immune system, and also benefiting the intestinal functionality of hybrid striped bass. [Copyright &y& Elsevier]

Highlights: [•] Ig μ and τ were analyzed in the Pacific bluefin tuna, Thunnus orientalis. [•] Repertoire analysis shows one shared diversity (DH) segment by μ and τ. [•] The shared DH segment suggests a divergent isotype control mechanism. [•] qPCR shows a lower relative predominance of IgM in the gills to IgT. [•] Ig μ and τ CDR3 lengths are similar in tuna, perhaps owing to the shared DH. [Copyright &y& Elsevier]

Abstract: A constraint for the expansion of cobia aquaculture is the availability of high quality formulated diets which reduce or eliminate fish meal (FM) protein. Therefore, the nutritive value of a novel soybean cultivar, Navita™ (Navita, non-genetically modified and selectively bred soy), and regular, commodity soybean meal (SBM, de-hulled, defatted, roasted and solvent-extracted) was evaluated for cobia, Rachycentron canadum via separate digestibility and growth trials. In the first experiment Navita's apparent digestibility coefficients (ADC) were higher than those of SBM for nearly every nutrient evaluated. Crude protein ADCs were 82 and 69% for Navita and SBM, respectively. Apparent DC for amino acids ranged from 68 to 109% for Navita whereas, amino acid ADCs for SBM varied from 42 to 98%. The feeding trial utilized fish of a size that more closely resembles commercial cobia stocking (1.8kg), and was conducted over a 91-day period. Experimental diets (iso-nitrogenous and iso-energetic) were formulated such that 67% of the FM protein in the reference diet was replaced by either a combination of SBM+soy protein concentrate (SPC, Solae Profine®) labeled MXSB-diet, or by a combination of SPC+Navita; Navita-diet, hereafter. A fourth experimental diet had 80% of the FM protein replaced by a combination of Navita+SPC and was identified as Navita-high. No significant differences (P >0.05) were observed in fish fed the experimental diets for feed conversion ratio, protein efficiency ratio, feed efficiency, mean daily intake, gross protein intake, gross energy intake, visceral somatic index, muscle ratio, and hepatosomatic index. Fish fed the Navita-high diet had the lowest fish in:fish out ratio (FIFO) at 0.9±0.16. These results indicate that Navita meal can be incorporated at very high levels in the diet of marine carnivorous fish such as cobia with no detriment to performance, making it a prime candidate for FM replacement in aquafeeds. [Copyright &y& Elsevier]

Aflatoxin B1 (AFB1) is a potent carcinogen that causes growth stunting, immunosuppression and liver cancer in multiple species. The recent trend of replacing fishmeal with plant-based proteins in fish feed has amplified the AFB1 exposure risk in farm-raised fish. NovaSil (NS), a calcium montmorillonite clay, has previously been shown to reduce AFB1 bioavailability safely and efficaciously in several mammalian species. This study was designed to: (1) evaluate AFB1 impact on cultured red drum, Sciaenops ocellatus, over the course of seven weeks; and (2) assess NS supplementation as a strategy to prevent aflatoxicosis. Fish were fed diets containing 0, 0.1, 0.25, 0.5, 1, 2, 3, or 5 ppm AFB1. Two additional treatment groups were fed either 5 ppm AFB1 + 1% NS or 5 ppm AFB1 + 2% NS. Aflatoxin B1 negatively impacted red drum weight gain, survival, feed efficiency, serum lysozyme concentration, hepatosomatic index (HSI), whole-body lipid levels, liver histopathological scoring, as well as trypsin inhibition. NovaSil inclusion in AFB1-contaminated diets improved weight gain, feed efficiency, serum lysozyme concentration, muscle somatic index, and intraperitoneal fat ratios compared to AFB1-treated fish. Although not significant, NS reduced AFB1-induced histopathological changes in the liver and decreased Proliferating Cell Nuclear Antigen (PCNA) staining. Importantly, NS supplementation improved overall health of AFB1-exposed red drum. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate the ability of NovaSil (NS) clay to sorb and mitigate the toxic effects of aflatoxin B1 (AFB1) in Nile tilapia (Oreochromis niloticus). Growth performance, targeted innate immunological function, intestinal microbial community and histology were evaluated after feeding tilapia diets with or without AFB1 and/or NS for 10weeks. Aflatoxin B1 at concentrations of 1.5 and 3.0ppm significantly (P <0.05) decreased weight gain, feed efficiency, hepatosomatic index and macrophage extracellular superoxide anion production in tilapia, regardless of NS addition to the diet. The overall results regarding the efficacy of NS were mixed; however, there was a trend (P =0.157) towards AFB1-toxicity prevention in regards to macrophage extracellular superoxide anion production. Additionally, when 0.5 and 1% NS was included in diets containing 1.5ppm AFB1, total histopathological score was lowered; however, this protective effect was not evident when fish were exposed to 3.0ppm AFB1. Denaturing gradient gel electrophoresis was performed to assess the effects of both AFB1 and NS on gut microbiota, but no significant differences were found among treatment groups. [Copyright &y& Elsevier]

Abstract: The relative importance of proteins (amino acids) and protein–lipid interactions for reproduction of channel catfish can be assessed qualitatively. We conducted a feeding/spawning trial to determine the effects of protein source and protein–lipid interactions of channel catfish broodstock diets on egg biochemical composition and egg and fry production. A general linear mixed model was used to examine statistical significance (α =0.05) among the diets and to compare the main effects using adjusted marginal means (Bonferroni) in order to examine the significance of the lipid source × protein source interaction (contrast statements). All diets contained 36% crude protein and the broodfish were fed on 69d of the 141-d trial based upon a water temperature dependent schedule. Broodfish fed an all plant protein (PP) diet with 10% fish oil (FO) had lower spawning success (33.3%) than fish fed three diets containing animal protein (58.3%). Fecundity of broodfish fed a control diet containing fish meal (FM), poultry byproduct meal (PBM) and 10% FO (6432±1915eggskg female−1), or a diet containing FM–PBM–5% FO and 5% poultry fat (PF);(6420±1930eggskg female−1) was greater than fecundity of fish fed the PP–FO diet (1072±371eggskg female−1), while fecundity of females fed a diet containing PBM and 10% FO was intermediate (4060±1261eggskg female−1). Total egg production was greater for fish fed the FM–PBM–FO–PF diet (38174.6±11031.8eggs·tank−1) than fish fed the PP–FO diet (6571.0±2212.1eggs·tank−1), while fish fed the FM–PBM–FO (32114.9±7034.4eggs·tank−1) or PBM–FO (20619.3±6084.1eggs·tank−1) diets had intermediate total egg production. Broodstock fed the FM–PBM–FO–PF diet produced heavier egg masses than broodstock fed the PBM–FO or PP–FO diets. The number of eggs per spawn was greater from fish fed the control and FM–PBM–FO–PF diets than from fish fed the PP–FO diet. No differences in protein-bound amino acid (AA) or free amino acid (FAA) composition were found among eggs when only dietary protein source (FM–PBM, PBM, or PP) was examined. A significant (P <0.05) dietary protein by lipid source interaction was found among diets when protein and lipid sources (diet) were used to examine FAA composition among eggs. Eggs produced by fish fed the FM–PBM–FO diet contained greater amounts of total FAA, essential isoleucine and leucine, and non-essential glycine, than eggs from fish fed the other diets. Eggs from broodfish fed the control or FM–PBM–FO–PF diets exhibited greater hatching success and total fry production than eggs from broodstock fed the PP–FO diet. A diet can be formulated to improve reproductive efficiency of channel catfish compared to current production diets. Results from the present experiment indicate that such a diet should contain 10% supplemental lipid as menhaden FO or a 1:1 or greater mixture of FO and PF. Also, the diet should contain 35% crude protein from a variety of plant and animal protein sources. Broodstock performance was enhanced when animal protein sources (two or more preferable) comprised at least 15% of the total diet and menhaden FM comprised at least one third of the animal protein sources. [Copyright &y& Elsevier]