Effects of Ala-Gln on Growth and Feed Intake of Cyprinus carpio var.jian Reared at Different Stocking Densities

Isonitrogen (350 g/kg CP) and isoenergetic(17 kJ/g) feed were formulated at five Ala-Gln levels (0,0.30%,0.60%,0.90% and 1.20%).Cyprinus carpio var.jian（10.07±0.15）g of three stocking density（20,40 and 80 g/L）were respectively fed with feed of five Ala-Gln levels. Effects of Ala-Gln on growth and feed intake of C. carpio var.jian reared at different stocking densities were investigated. Results indicated that feed intake and protein productive ratio were significantly lower with the increase of stocking density, but coefficient of mass variation was higher（P<0.05）.In a certain range of Ala-Gln, growth of C. carpio var.jian improved with the increase of feed intake and protein productive ratio and the decrease of coefficient of mass variation（P<0.05）.Under the current conditions,it could be concluded that optimum Ala-Gln level for C. carpio var.jian in the stocking densities of 20, 40 and 80 g/L should respectively be 0.30%-0.60%,0.60%-0.88% and 0.90%-1.08%.