Growth, nutritional efficiency, and profitability of juvenile GIFT strain of Nile tilapia (Oreochromis niloticus) reared in biofloc system on graded feeding rates

Abstract

This study was conducted to evaluate the effects of the feeding rate (0%, 2.5%, 5.0%, 7.5%, and 10% of body weight per day; BW.d−1) on growth performance, nutritional efficiency, and profitability of Nile tilapia (Oreochromis niloticus) juveniles (3.1 ± 0.1 g) using the biofloc technology (BFT) system for 70 days. Fish were randomly stocked (15 fish. Tank−1) in 24 experimental units (50 L), while water quality parameters remained within acceptable limits for the species during the experiment. Animal performance parameters were influenced by feeding rates (P < 0.05), but not survival (P > 0.05), which remained around 81%. Final body weight, weight gain, and thermal growth coefficient increased significantly (P < 0.05); however, the gradual increase in feeding rates had reduced feed efficiency, protein, and energy productive values (P < 0.05). Whole-body lipid and gross energy increased significantly (P < 0.05) as the feeding rate increased, while the moisture content showed an opposite trend up to 5.0% BW.d−1. The results show that Nile tilapia juveniles raised in the BFT system should be fed between 4.3 and 6.1% BW.d−1 to exhibit improved profitability and growth.