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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]

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: 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]

The effects of four prebiotics (fructo-oligosaccharide, Bio-MOS, transgalacto-oligosaccharide and GroBiotic-A) on digestive enzymes and intestinal morphology were studied in juvenile hybrid striped bass (Morone chrysops × M. saxatilis) and red drum (Sciaenops ocellatus) using two separate 8-week feeding trials. Red drum were fed experimental diets with the four prebiotics each individually supplemented at 1% and hybrid striped bass were fed diets supplemented with GroBiotic-A at 1 and 2%. Both trials were conducted with each diet fed to apparent satiation twice per d to three replicate groups of fifteen juvenile fish. For histomorphological analysis, gastrointestinal tract (GIT) samples from three randomly selected fish per tank were taken at 4 and 8 weeks for hybrid striped bass and at 8 weeks for red drum. For both trials, GIT samples from two randomly selected fish per tank were taken at 4 and 8 weeks and analysed for pepsin, trypsin, chymotrypsin, aminopeptidase, α-amylase, lipase, and both acid and alkaline phosphatase activities. The results of the histological evaluation indicated that the inclusion of prebiotics was adequate to elicit structural changes in the GIT of both species. On the other hand, no significant changes in the enzyme activities were detected at week 8 in both species. However, there was a transient effect of Bio-MOS supplementation on the activities of aminopeptidase, α-amylase and alkaline phosphatase at week 4 in red drum only. Thus, previously observed improvements in nutrient digestibility by these fish in response to prebiotic supplementation appear to be mostly related to changes in GIT structure as opposed to the enhancement of digestive enzyme activity.