Replacement of fishmeal with poultry by-product meal in the diet of Florida pompano Trachinotus carolinus L.

Abstract

The development of cost-effective and growth-promoting diets for Florida pompano (Trachinotus carolinus L.) is necessary for a feasible pompano aquaculture industry in the United States. However, research efforts to reduce the utilization of marine ingredients in aquatic feeds are needed to accomplish such a goal. Three independent growth trials were conducted to evaluate the replacement of fishmeal in the diet of Florida pompano. The basal diets were formulated to contain 40% crude protein and 10% lipid using solvent extracted soybean meal and corn gluten as the primary and fixed protein sources. In Trial I (10weeks) the basal diet containing 15% fishmeal (FM15) was modified by the isonitrogenous replacement of fishmeal with poultry by-product meal resulting in diets containing 10% (FM10), 5% (FM5) and 0% (FM0) fishmeal. In Trial II (12weeks), the FM0 diet was supplemented with methionine (M), lysine (L), and taurine (T), serving as the basal diet (MLT) for the evaluation of potential limitations in these amino acids. By deleting individual amino acids, test diets without methionine (LT), lysine (MT) or taurine (ML) supplements were formulated. In Trial III (8weeks), the FM0 diet from Trial I served as the basal diet (0% Tau) for the evaluation of potential limitations in taurine. Fish in replicate tanks (n=3) were fed one of the randomly assigned test diets two times daily. The total replacement of fishmeal in Trial I resulted in depression of fish performance while the performance of fish offered test diets with 5–15% fishmeal did not differ significantly. Reductions in weight gain (from 338.1 to 260.4%), feed efficiency (from 0.53 to 0.40), protein and energy retention (from 19.6 to 12.4% and from 20.4 to14.2%, respectively) were observed in fish fed the FM15 and FM0 diets, respectively (P<0.05). In Trial II, growth performance of pompano did not change (P>0.05) by the removal of supplemental methionine, lysine or taurine from the FM0 diet albeit, numerically the removal of taurine produced the smallest fish. In Trial III, the supplementation of taurine to the FM0 diet at 0.75g/100 (0.75% Tau) improved the weight gain (from 587.7 to 773.3%), feed efficiency (from 0.50 to 0.64), and protein retention (from 20.5 to 24.3%) of pompano (P<0.05). Based on these results, we concluded that poultry by-product meal is a good alternative ingredient for fishmeal in the diet of Florida pompano and that this species appears to have a minimum dietary requirement for taurine.