Partial and full replacement of menhaden fishmeal protein by soybean meal protein supplemented with or without amino acids and attractants in the diets of juvenile black sea bass Centropristis striata.
Presentation
Overview
Overview
Description
A series of experiments were conducted to test the effect of varying dietary levels of solvent-extracted soybean meal supplemented with or without amino acids and attractants in the diets of juvenile black sea bass. In experiment 1, seven diets were formulated replacing menhaden fishmeal protein (FP) by soybean meal protein (SP) at 0, 10, 20, 30, 40, 50, and 60% without supplementing amino acids but adding 1% attractants. In experiment 2, six diets were formulated replacing FP by SP at 0, 60, 70, 80, 90 and 100% without supplementing amino acids but adding 1% attractants. Experiment 3 and 4 were designed the same as experiments 1 and 2, respectively, but without attractants. Experiment 5 was designed as experiment 4, but supplementing coated L-methionine and L-lysine. In each experiment, diets were formulated to have about the same protein (44% crude protein) and lipid level (10% lipid). All diets contained 7.5% squid meal and 5% krill meal. Each test diet was fed to triplicate groups of juvenile black sea bass held at 15 fish per 74-L recirculating sea water tank for 6 weeks in experiments 1, 3 and 4, 5 and 10 weeks in experiment 2. The fish were fed two times a day up to apparent satiation.
After the feeding trials, survival was more than 85% in all experiments, and there were no significant differences in survival among treatments in all five experiments. In experiment 1, growth results showed no significant differences (P<0.05) in body weight gain (BWG) among fish fed diets replacing 0% to 60% FP by SP. In experiment 2, BWG decreased significantly when FP was replaced by SP at more than 70% in the diets. Experiments 3 and 4 suggested that FP replacement by SP could be not more than 60% without supplementing attractants in the diets. Experiment 5 indicated that supplementation of methionine and lysine could increase BWG slightly compared to diets without supplementation. Feed conversion efficiency, specific growth rate, feed intake and protein efficiency for each experiment will be presented. Body proximate composition of the fish was analyzed and will be discussed in relation to the replacement level of FP by SP for each experiment.
Results of these experiments indicated that the optimum level of FP replacement with solvent extracted SP was 70% with 7.5% squid meal and 5% krill meal and with or without supplementing methionine and lysine in the diets without impairing growth of juvenile black sea bass. An experiment to test the replacement of FP by SP without adding squid meal and krill meal is in progress. These results will be used to develop environmentally-sound and cost-effective pre-dominantly plant protein based diets for the aquaculture of black sea bass.
