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Seven potential feed ingredients were evaluated for digestibility with Florida pompano Trachinotus carolinus using extruded diets. Ingredients included Special Select™ menhaden meal, fishery processing by-product (Montlake meal), NuPro® yeast extract, canola protein concentrate, corn protein concentrate, barley protein concentrate and Spirulina. Digestibility values were determined when fish were held at 3 and 28 g L−1 salinity to determine the effect of salinity on digestibility. With the exception of the canola protein concentrate, the coefficients were numerically higher in pompano held at 28 g L−1. No significant differences were detected for apparent crude protein or apparent energy digestibility between the two salinities. Amino acids were highly available from the two marine-based ingredients and the barley and canola concentrates. The availability of alanine, leucine, isoleucine and phenylalanine was significantly higher ( P < 0.05) from the barley protein concentrate at 28 g L−1 than 3 g L−1 salinity. Methionine and phenylalanine were highly available from all the ingredients except the yeast protein. Conversely, glycine was not well utilised from any of the ingredients. The apparent digestibility coefficients provided here allow for more precise formulation of diets for Florida pompano reared in both seawater and low-salinity environments. [ABSTRACT FROM AUTHOR]

Our recent results in hybrid striped bass (HSB) concluded that ideal protein theory accurately predicts first-limiting amino acids in commercial diet formulations if accurate amino acid availability data are used and that appropriate levels of supplemental lysine are needed to improve fish performance from fishmeal-free diets. Our goal in this study was to elucidate how dietary lysine supplementation of a commercial fishmealfree diet influences the expression of two genes, myostatin and myogenin, controlling myogenesis in differentially growing groups of HSB. Real-time RT-PCR results in HSB suggest that the levels of lysine added to the diet (17.8, 35.1, 51.0 g kg -1 of diet) has an impact on myogenin relative to the basal unsupplemented diet, but no effect on myostatin. Moreover, our data further suggest that the amount of dietary lysine supplementation influenced the ratio of myostatin/myogenin expression in HSB and that this pattern mimicked that of most of the growth, composition of growth and nutrient retention data from our previous study and may therefore be a useful marker for selecting fish for improved growth performance. [ABSTRACT FROM AUTHOR]

Apparent digestibility coefficients ( ADCs) of nutrients (crude protein, amino acids, crude lipid, fatty acids, and minerals) were determined for fish meals derived from menhaden, Asian carp (combination of silver and bighead carps), and common carp in feeds for hybrid striped bass and rainbow trout. Extruded test diets were formulated to contain a 70 : 30 mixture of reference diet and test ingredient with yttrium oxide (1 g kg−1) serving as the inert marker. Diets were randomly assigned to triplicate tanks and fish were fed once per day at 2% body weight. Fecal samples were collected by manual stripping. The ADCs were calculated according to standard procedures. The composition and digestibility of Asian carp and common carp meals was broadly similar to menhaden meal. Protein digestibility ranged from 86.5% (Asian carp meal) to 93.1% (common carp meal). Lipid was highly digestible with ADCs >100% for all ingredients. Although the Asian carp meal was less digestible than the other two fish meals, it was still a highly digestible ingredient. Our data suggest that fish meals derived from Asian or common carp would be valuable feedstuffs in diets for hybrid striped bass, rainbow trout, and possibly other cultured fishes. [ABSTRACT FROM AUTHOR]

The refinement of hybrid striped bass feed formulations has been progressing rapidly. There is still, however, limited information available regarding nutrient digestibility and amino acid availability from common feedstuffs. A pair of experiments was conducted to determine the protein digestibility and amino acid availability to sunshine bass from an assortment of commercially available animal protein feedstuffs, blended animal products and plant protein feedstuffs in extruded diets. The feedstuffs tested were blood meal, poultry by-product meal, fish solubles, Pro-Pak 60, Pro-Pak 65, ProCon 65RDB, and 60FMC for the animal protein feedstuffs and brewer's yeast, canola meal, peanut meal, and sunflower meal for the plant protein feedstuffs. Test diets consisted of a mixture of nutritionally complete reference diet and test ingredient. Triplicate tanks of fish were fed their respective diets for 7 days prior to collection of faeces by stripping. Apparent digestibility coefficients of protein (ADC-CP) in the animal products ranged from 47% for 60FMC to a high of 70% for fish solubles. ADC-CPs for animal products were not different across products. Blood meal, poultry by-product meal, Pro-Pak 60, Pro-Pak 65, and ProCon had intermediate ADC-CPs of 63, 55, 63, 57 and 52%, respectively. ADC-CP in plant feedstuffs ranged from 43% for canola meal to 80% for peanut meal. Brewer's yeast, canola meal, and sunflower meal had intermediate ADC-CPs at 54, 43 and 69%, respectively. Apparent amino acid availability coefficients were variable across animal products and did not necessarily correlate to the ADC-CPs for a given feedstuff. Isoleucine availability was low in blood meal at 38% compared with 59% or better for the remaining amino acids. Lysine, tyrosine and phenylalanine availability from fish solubles was low at 31, 35 and 44%, respectively. Amino acid availability from Pro-Pak 60 was consistently higher across all amino acids for the animal products and blends tested. Of the plant products tested, peanut meal was the best performing feedstuff relative to amino acid availability. [ABSTRACT FROM AUTHOR]