THE STUDY ON SELENIUM NUTRITION: OPTIMUM DIETARY SELENIUM REQUIREMENT IN JUVENILE NILE TALIPIA, Oreochromis niloticus  

Qing Pan*, Tan Yuwen, Wu Shuanglong, Chen Feng
Department of Aquaculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China (qpan@scau.edu.cn )

An 8-week feeding experiment was conducted to estimate the optimum dietary selenium requirement for juvenile Nile tilapia, Oreochromis niloticus. Selenomethionine was added to the basal diet at 0, 0.20, 0.40, 0.60, 0.80 and 1.00 mg Se/kg respectively. Each diet was fed to triplicate groups of juvenile fish with average initial body weight of 3.00g in a recirculated-water system. The result showed that the final average body weight, weight gain, specific growth rate, feed efficiency and protein efficiency ratio of 0.60 mg/kg group were significantly higher than those of the control group (P<0.05). Viscerosomatic index and hepatosomatic index of selenomethionine-added groups were lower than those of the control group, while condition factor, whole body composition (except crude lipid) and muscle composition of tilapia were not significantly different among all groups (P>0.05). Whole body crude lipid contents in groups with selenium supplementation were significantly higher than that in control group (P<0.05). Based on the broke-line regression analysis of weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) (the following figures), the dietary selenium requirement of juvenile Nile tilapia was recommended at 0.57mg Se/kg diet.