Effects of dietary growth promoter supplementation on growth performance and non- specific immunity function in rainbow trout Oncorhynchus mykiss
LI Chan, BAI Lan, XU Qi-you, XU Hong, ZHANG Tie-qi
1. Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China; 2. School of Life Science and Technology, Dalian Fisheries Univ. , Dalian 116023, China
Abstract: An 8 week feeding trial was undertaken to evaluate the effects of dietary growth promoter supplementation including Nosiheptide（2 mg/kg, 4 mg/kg）, Allitridum（ 15 mg/kg） and Flavomycin （8 mg/kg） on growth performance and non- specific immunity in rainbow trout Oncorhynchus mykiss with initial average body weight of （ 33.78 ± 1.99） g at water temperature of （ 14.5 ± 2.0） ℃. Triplicate groups of 80 rainbow trout juveniles held under identical culture conditions （ disolved oxygen level of 8.9 ± 1. 1 mg/L） were fed twice daily to satiation one of five diets with equivalent protein （43.05%） and lipid （23.02%） content on a dry weight basis, but with supple mented with Nosiheptide at a rate of 2 mg/kg, and 4 mg/kg）, Allitridum at a rate of 15 mg/kg and Flavomycin at a rate of 8 mg/kg and without any growth promoter. The results showed that the juveniles fed the diet containing 2 mg/kg Nosiheptide, 15 mg/kg Allitridum and 8 mg/kg Flavomycin had 8.5% , 6.9% and 8.5% higher specific growth rate （SGR） than the fish in the control group, and 8.3%, 7.5% and 2.5% lower feed conversion ratio （FCR） than the fish in the control group. There were 13.4% , 10.35% and 12.62% higher weight gain rate （WGR） and 2.69% and 8.58% and 2.88% higher crude protein contents in the juveniles fed the diets containing 2 mg/kg Nosiheptide, 15 mg/kg Allitridum and 8 mg/kg Flavomycin than in the juveniles the control group, respectively. The activities of SOD significantly increased（ P 〈0.05 ） in kidney and the activities of lysozyme （LSZ） significantly increased（P 〈 0.05 ） in liver of the fish fed the diet supplemented with different levels of dietary growth promoters. The activities of SOD in liver and plasma and the activities of LSZ in gill were increased. It can be concluded that the growth performance and non - specific immunity of rainbow trout could be improved evidently by addition of 2 mg/kg nosiheptide and 15 mg/kg allitridum and 8 mg/kg Flavomyein.
2008, Vol. 23 
