Growth performance of sea bass fed increasing levels of pea-wheat protein in diets varying in fish meal quality

A 11-week trial was carried out to compare the growth performance of sea bass (D. labrax) fed six isonitrogenous isocaloric diets where protein from two fish meals of different nutritive value was replaced with graded levels (0, 50 or 75%) of a mixture made up by a pea protein concentrate and wheat gluten. Fish meal quality did not affect (P>0.05) weight gain or feed efficiency in fish fed graded levels of plant protein in the diet. Feed intake decreased (P<0.05) as the level of plant protein was increased in the diet but this did not led to impaired growth or feed conversion rate. Protein efficiency and retention were equally improved (P<0.05) only with diets where a poor quality fish meal was substituted by protein rich-plant ingredients. Calculations based on the mass balance of nutrients of sea bass proven the inclusion of a mixture of highly purified plant-protein derivatives in complete diets for the sea bass, to be beneficial in reducing pollution load.