Digestibility of gross nutrients by sunshine bass in animal by products and commercially blended products used as fish meal replacements

To more accurately formulate feeds for hybrid striped bass (white bass Morone chrysops X striped bass M. saxatilis), data on the availability of nutrients from feedstuffs are needed to complement information on nutritional requirements. An experiment was conducted to determine the apparent digestibility coefficients (ADCs) of protein, lipid, energy, and organic matter for an assortment of commercially available feedstuffs and blended products used as fish meal replacements. The feedstuffs tested were ring-dried blood meal, poultry by-product meal, fish solubles, and four commercially blended fish meal substitutes (PRO-PAK, PRO-PAK 65, Pro-Con 65RDB, and 60FMC). Organic matter ADCs for these products ranged from 47% for 60FMC to 130% for fish solubles, while energy ADCs paralleled these values and ranged from 48% (60FMC) to 114% (fish solubles). Lipid ADCs ranged from 49% for PRO-PAK 65 to 79% for poultry by-product meal, and protein ADCs ranged from 47% for 60FMC to 70% for fish solubles. These values provide needed information to feed manufacturers and will allow for more accurate substitutions for these feedstuffs in aquafeeds.