饲料蛋白质和脂肪水平对亚东鲑亲鱼生长性能、消化酶活性和血清指标的影响

摘要

This study was conducted to estimate the effects of dietary protein and lipid levels on growth performance, gonad index, digestive enzyme activities and serum indices of Salmo trutta fario broodstock.Ten kinds of practical experimental diets were formulated to contain five protein levels (36％, 39％, 42％, 45％and 48％) and two lipid levels (9％ and 18％) using 5×2 two-factor randomized design, and each diet was randomly assigned 3 replicates of 19 bloodstocks.The Salmo trutta fario with the initial body weight of(462.53±45.40) g were cultured in the water flow-through system for 77 days.The results showed as follows:weight gain rate was increased with the increase of dietary protein level under the same lipid level, on the contrary, feed conversion ratio was gradually decreased, but was increased at the 48％ dietary protein level.Dietary protein and lipid levels had no significant effect on the gonad index of female bloodstocks (P>0.05).The gonad index of male bloodstocks was decreased firstly with the increase of dietary protein level, and then was increased at the 48％ dietary protein level.The lipase activity of stomach, intestine and pyloric caeca was gradually increased with the increase of dietary protein level under the same lipid level, and 48％ dietary protein level was significantly higher than 36％ dietary protein level (P<0.05), the protease activity of stomach, intestine and pyloric caeca was also increased, but no significant difference was observed among the groups (P>0.05).Under the same protein level, the protease and lipase activities of stomach, intestine and pyloric caeca in 18％ lipid level groups were slightly higher than those in 9％ lipid level groups.The serum ammonia content was gradually increased with the increase of dietary protein level under the same lipid level.Dietary protein and lipid levels had no significant effect on the activities of serum superoxide dismutase and lysozyme, and the contents of malonaldehyde, glucose, triglyceride, total protein, albumin (P>0.05).In conclusion, Salmo trutta fario broodstock can respond to dietary protein (36％ to 48％) and lipid (9％ to 18％) levels.With the weight gain rate as an index, the dietary protein requirement for Salmo trutta fario broodstock is 43.11％ and 45.69％when the dietary lipid level is 9％ and 18％ base on the broken-line model analysis, respectively.[Chinese%本试验旨在研究饲料蛋白质和脂肪水平对亚东鲑亲鱼生长性能、性腺指数、消化酶活性和血清指标的影响.试验采用5×2两因素随机设计,设5个蛋白质水平(36％、39％、42％、45％、48％)和2个脂肪水平(9％、18％),共配制10种实用试验饲料.每种试验饲料投喂3个重复,每个重复19尾鱼.初重为(462.53±45.40)g亚东鲑在室内水族箱中流水饲养,饲养周期为77 d.结果表明:同一脂肪水平下,随饲料蛋白质水平的升高,增重率有所升高,而饲料系数逐渐降低,至蛋白质水平为48％时又有所升高.饲料蛋白质和脂肪水平对雌性亲鱼性腺指数无显著影响(P>0.05),雄性亲鱼性腺指数随蛋白质水平的升高而降低,但至蛋白质水平为48％时又有所回升.同一脂肪水平下,随着饲料蛋白质水平的升高,胃、肠道和幽门盲囊的脂肪酶活性逐渐增加,蛋白质水平为48％时显著高于蛋白质水平为36％时(P<0.05);而胃、肠道和幽门盲囊的蛋白酶活性虽有所增加,但各组间无显著差异(P>0.05).同一蛋白质水平下,18％脂肪水平组胃、肠道和幽门盲囊的蛋白酶和脂肪酶活性均略高于9％脂肪水平组.同一脂肪水平下,血清氨含量随饲料蛋白质水平的升高而逐渐增加.饲料蛋白质和脂肪水平对血清超氧化物歧化酶、溶菌酶活性以及葡萄糖、甘油三酯、总蛋白、白蛋白和丙二醛含量均未产生显著影响(P>0.05).由此得出,亚东鲑亲鱼对饲料蛋白质(36％ ～48％)和脂肪(9％～18％)水平有一定的适应性反应;以增重率为指标进行折线模型分析,得出饲料脂肪水平为9％和18％时,亚东鲑亲鱼对蛋白质需要量分别为43.11％和45.69％.