Organic diet supplemented with fish residuum flour for Nile tilapia juveniles

Abstract

This work was carried out to evaluate the inclusion of fish by-product from the filleting industry in organic food for Nile tilapia (O. niloticus) in the phase of growth, on livestock performance (weight gain, food conversion and survival), characteristics of carcass (carcass yield, clear trunk, fillet, visceral fat and hepatosomatic index) and chemical composition (humidity, gross protein, mineral matter and ethereal extract) of fish. A total of 440 tilapias with 84.11 ± 11.56 g average initial weight and 16.7 ± 0.80 cm in length, assigned into 20 8m³-aquaria, in a completely randomized design with five treatments and four replications. Four diets were prepared with levels of 0; 4; 8; 12 and 16% of fish by-product meal, with 28% in digestible protein and 3,100 kcal kg^-1 in digestible energy. There was a linear increase in the average of weight gain. However, no differences were observed (P < 0.05) for food conversion and survival. There were no significant differences (P > 0.05) for the treatments of body yield, humidity and gross protein of fillets. The mineral matter and the ethereal extract, on the other hand, showed differences (P < 0.05) among the treatments. The inclusion of 16% in fish by-product wastes from the filleting industry in diets formulated with ingredients certificated from organic origin improves livestock performance, does not impair body yield, but it alters the parameters of mineral matter and ethereal extract of tilapia in the phase of growth.