Metabolic, Antioxidant and Hematologic Adjustment of Red Tilapia (Oreochromis sp) Fed Commercial Diets with Different Protein Levels and Reared in Sea Water with Biofloc

Abstract

This study was conducted to evaluate the physiological response of juvenile red tilapia Oreochromis sp. (initial average body weight of 2.82 ± 0.02 g) reared in seawater with biofloc and fed extruded commercial diets containing 25, 35 and 40% of crude protein (P25, P35 and P40, respectively). After 7 weeks of assay, fish fed P35 and P40 showed similar weight gain, specific growth rate, fed conversion ratio and Fulton's condition factor. Both, P35 and P40 showed higher values of growth performance than P25 treatment. Otherwise, fish from P35 showed the lower activity of metabolic enzymes (ASAT, ALAT, GK, FBPase, G6PD and FAS) than P40. While, fish from P25 showed the highest levels of catalase activity and lower values of hepatic lipid peroxidation (like MDA). However, the decrease in protein in the diets was reflected in the decrease in Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration, as well as a decrease in the concentration of albumin in the blood plasma. In conclusion, the marine biofloc allows hybrid red tilapia juveniles to be fed with 35% CP without compromising their productive performance, antioxidant system and hematological parameters.