饲料脂肪水平对胭脂鱼生长性能、肠道消化酶活性和脂肪代谢的影响

Effects of Dietary Lipid Levels on Growth Performance,Intestinal Digestive Enzyme Activities and Lipid Metabolism of Chinese Sucker(Myxocyprinus asiaticus)

试验选用平均体重为（6.73±0.21）g的胭脂鱼（Myxocyprinus asiaticus）幼鱼540尾,随机分成6个组（每组3个重复,每个重复30尾）,分别饲喂脂肪水平为2.04%、4.43%、6.88%、9.02%、11.98%和13.39%的试验饲料,研究脂肪水平对胭脂鱼生长性能、肠道消化酶活性及脂肪代谢的影响。试验期为56d。结果表明：1）饲料脂肪水平对胭脂鱼的生长性能有显著影响（P〈0.05）。当添加量为6.88%时,胭脂鱼增重率、特定生长率和RNA与DNA比值达到最大值,饲料系数达到最小值,二元回归分析确定当增重率和饲料系数达到极值时,饲料脂肪水平分别为6.62%和7.02%,能蛋比分别为45.77和45.96kJ/g;2）饲料脂肪水平显著影响胭脂鱼肠道消化酶活性（P〈0.05）,随着饲料脂肪水平增加,蛋白酶活性逐渐降低,脂肪酶活性先升高后稳定,淀粉酶活性则先降低后稳定,转折点均出现在脂肪水平为6.88%时;3）饲料脂肪水平对脂肪代谢亦有显著影响（P〈0.05）,随饲料脂肪水平增加,血清总脂、甘油三酯和总胆固醇含量增加,肝胰脏苹果酸脱氢酶和血清脂蛋白脂酶活性降低。由此得出,胭脂鱼的适宜脂肪水平为6.62%~7.02%,最佳能蛋比为45.77~45.96kJ/g;饲料脂肪水平增加,使肠道蛋白酶和淀粉酶活性受到抑制,血脂水平增加,脂肪合成代谢酶和脂肪分解酶活性降低。

Five hundred and forty Chinese sucker（Myxocyprinus asiaticus）with average body weight of（6.73±0.21）g were randomly divided into 6 treatments with 3 replicates in each treatment and 30 fish in each replicate to investigate the effects of dietary lipid levels on growth performance,intestinal digestive enzyme activities and lipid metabolism of Chinese sucker by feeding diets with six lipid levels（2.04%,4.43%,6.88%,9.02%,11.98% and 13.39%）.After a 56-day feeding trial,the results showed as follows：dietary lipid levels had significant effect on the growth performance of Chinese sucker（P0.05）.At the 6.88% level,the weight gain rate,special gain rate and RNA to DNA ratio reached the maximum,while the feed conversation ratio got the minimum.According to the second-order regression,the optimal dietary lipid level of Chinese sucker had the extremum of weight gain rate and feed conversation ratio was 6.62% and 7.02%,respectively,and the optimal energy to protein ratio was 45.77 and 45.96 kJ/g,respectively.Dietary lipid levels had significant effect on the intestinal digestive enzyme activities of Chinese sucker（P0.05）.With the increase of dietary lipid levels,the protease activity was decreased,and the lipase activity was increased at first and then maintained at a steady state,while the amylase activity was decreased at first and then maintained at a steady state.Dietary lipid levels had significant effect on the lipid metabolism of Chinese sucker（P0.05）.With the increase of dietary lipid levels,contents of total lipid,triglyceride and total cholesterol in serum were increased and activities of malate dehydrogenase in hepatopancreas and lipoprotein lipase in serum were decreased.In conclusion,the optimal dietary lipid level of juvenile Chinese sucker was 6.62%～7.02%,and the optimal energy to protein ratio was 45.77～45.96 kJ/g.Protease and amylase activities were negatively correlated with high dietary lipid levels.Serum lipid level was increased and enzyme activities for lipogenic and lipolysis function were decreased with the increasing of dietary lipid levels.