水温和饲料蛋白质水平对松浦镜鲤幼鱼肠道消化酶活性的影响

摘要

本试验旨在研究水温和饲料蛋白质水平对松浦镜鲤(Cyprinus specularis Songpu)幼鱼肠道消化酶活性的影响.选取平均体重为(10.11±1.07)g的松浦镜鲤幼鱼1350尾,随机分成15组,每组3个重复,每个重复30尾鱼.试验鱼在不同水温(18、23和28℃)下饲喂不同蛋白质水平(30.0％、32.0％、34.0％、36.0％和38.0％)的5种饲料.试验期为60 d.结果表明:水温对松浦镜鲤幼鱼肠道蛋白酶、淀粉酶和脂肪酶活性均有显著或极显著影响(P ＜0.05或P＜0.01).饲料蛋白质水平对前肠、中肠和后肠蛋白酶以及前肠淀粉酶活性有显著或极显著影响(P＜0.05或P＜0.01).除了前肠蛋白酶活性外,水温和饲料蛋白质水平的交互作用对各肠段蛋白酶、淀粉酶和脂肪酶活性均未产生显著影响(P＞0.05).同一水温下,随饲料蛋白质水平的升高,肠道蛋白酶、淀粉酶和脂肪酶活性均呈现先升高后降低的变化趋势；同一饲料蛋白质水平下,肠道蛋白酶和淀粉酶活性随水温升高而升高,而脂肪酶活性则随水温的升高而降低.由此得出,水温和饲料蛋白质水平与松浦镜鲤幼鱼肠道消化酶活性关系密切；根据肠道蛋白酶活性,松浦镜鲤幼鱼最佳饲料蛋白质水平在水温18℃下为35.83％ ～ 36.96％,23℃下为37.40％～39.58％,28℃下为36.79％ ～39.99％.%This experiment was conducted to investigate the effects of water temperature and dietary protein level on intestinal digestive enzyme activities of juvenile Songpu mirror carp ( Cyprinus specularis Songpu). A total of 1 350 juvenile Songpu mirror carp with an average body weight of (10.11 ±1. 07) g were randomly assigned to 15 groups with 3 replicates per group and 30 fish per replicate. Juvenile Songpu mirror carp were fed five diets containing 30. 0% , 32. 0% , 34. 0% , 36. 0% and 38. 0% protein, respectively, and reared at different water temperatures (18, 23 and 28 ℃) for 60 days. The results showed as follows: water temperature significantly influenced the activities of protease, amylase and lipase in foregut, midgut and hindgut (P < 0.05 or P <0. 01). The protease activity in foregut, midgut and hindgut and foregut amylase activity were significantly influenced by dietary protein level (P<0.05 or P<0.01). In addition to foregut protease activity, the interaction effect between water temperature and dietary protein level was not significantly affected the activities of protease, amylase and lipase in each intestinal section (P >0. 05). At the same water temperature, the activities of protease, amylase and lipase in intestine were firstly increased and then decreased with the dietary protein level increasing; at the same dietary protein level, the activities of protease and amylase in intestine were increased with the water temperature increasing, while the lipase activity in intestine was decreased. In conclusion, the water temperature and dietary protein level are closely related to the intestinal digestive enzyme activities of juvenile Songpu mirror carp. Based on the intestinal protease activity, the optimal dietary protein requirements for juvenile Songpu mirror carp in different water temperatures are 35.83% to 36. 96% at 18 ℃, 37.40% to 39. 58% at 23 ℃, and 36. 79% to 39. 99% at 28 ℃.