Proximate Composition of Bioflocs in Culture Systems Containing Hybrid Red Tilapia Fed Diets with Varying Levels of Vegetable Meal Inclusion

Abstract

Biofloc culture systems, which are based on the development of microorganisms that recycle inorganic nutrients and organic matter, may contribute to the nutrition of some farmed species. Juvenile red tilapia (Nile Tilapia Oreochromis niloticus × Mozambique Tilapia O. mossambicus) cultured in saltwater were fed pelleted diets in which 0, 33, 67, or 100% of the fish meal was substituted with a vegetable meal mix (corn, wheat, and sorghum meals). The proximate composition of the biofloc produced in the culture systems was evaluated. Four experimental diets and one control diet (isocaloric and isoproteic) were randomly assigned to 15 experimental tanks. Samples of biofloc were periodically collected to measure the total suspended solids, organic matter, and ash content and to determine the protein, lipid, and carbohydrate contents. At the end of the study, variables describing red tilapia production were determined. The biofloc volume, total suspended solids, ash, and organic matter showed significant differences among treatments, but carbohydrate (33.0–39.0%), lipid (2.6–3.5%), and protein (23.7–25.4%) levels were similar. No significant differences were observed in red tilapia survival, final biomass, or feed conversion ratio. We conclude that the substitution of fish meal with vegetable meal in the pelleted feed had no adverse effect on the production response of saltwater‐cultured red tilapia.