Dietary taurine improves reproductive performance of Nile tilapia (Oreochromis niloticus) broodstock

Abstract

This study was conducted to evaluate the effects of supplemental taurine on reproductive performance of Nile tilapia (Oreochromis niloticus) broodstock fed soybean meal-based diets. Four isonitrogenous (350 g kg−1 protein), isocaloric (18 MJ kg−1) diets were formulated to contain 0, 5, 10 and 15 g kg−1 taurine. The diets were fed to triplicate groups of juvenile Nile tilapia (10–15 g average body weight) at a female: male ratio of 3 : 1, to apparent satiation, three times per day for 130 days. The size at first maturation decreased with increasing dietary taurine to 10 g kg−1 and levelled off with further taurine supplementation. The time to first spawning was also significantly shorter at 10 g kg−1 taurine level. Spawning performances, including spawning frequencies, total number of spawnings per tank, number of spawnings per female and absolute fecundity, were all significantly improved with increasing dietary taurine up to 10 g kg−1. However, the quadratic regression analyses indicated that the maximum spawning performance occurred at 8 g kg−1 of supplemental taurine. Eggs produced from broodstock fed 10 g kg−1 taurine exhibited significantly higher hatchability and required shorter time for hatching and yolk-sac absorption and also resulted in higher larval weight than at other dietary taurine levels. The highest egg protein, total amino acids and taurine were also obtained at 10 g kg−1 taurine. These results suggest that 8 g kg−1 dietary taurine is required for optimum reproductive outputs of Nile tilapia broodstock.