Effects of dietary supplementation time with Schizochytrium microalgae meal on growth, meat quality and fatty acid composition of Nile tilapia

Abstract

Five hundred Nile tilapia were fed with two diets (with or without microalgae Schizochytrium sp. meal) for different periods (0, 15, 30, 45 and 60 days). The aim of the present study was to investigate the effects of the time of supply of Schizochytrium sp microalgae meat in the diet on growth, fatty acid profile and meat quality of Nile tilapia. At growth performance, only the feed consumption and the final weight of the animals varied quadratically, reducing the estimated period to 37 and 38 days respectively. For the characteristics of tilapia fillet meat, only the variable b* (yellowness) showed higher values (2.48) at 30 days of microalgae supply, differing from the control treatment. There was a quadratic effect (p < 0.05) for the total contents of omega-3 and DHA in the fillet with maximum deposition at 49 days and 52 days respectively. The levels of total omega-3 fatty acids and DHA in the head, viscera and spine of Nile tilapia increased linearly (p < 0.05) with the increase in the period of offering diets containing Schizochytrium sp. microalgae. Our results suggest that the supply of diets containing Shizochytrium sp microalgae meal for 49 days is enough to increase the omega-3 content, with massive participation of DHA, in the tilapia fillet without changing other parameters of its quality and zootechnical performance. With this period, the residues obtained from filleting, such as the head, spine and viscera, also benefit from an increase in omega-3 and DHA.