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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]

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: 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]

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]

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]