饵料中不同淀粉水平对中华绒螯蟹消化酶活力的影响

Effect of different dietary starch levels on digestive enzyme activity of Eriocheir sinensis

试验旨在探究中华绒螯蟹肝胰脏和肠道中消化酶最适温度和pH值,研究饵料中小麦淀粉水平对中华绒螯蟹消化酶比活力的影响。选择平均体重为(10.0±0.1) g的中华绒螯蟹300只,随机分为5组,每组3个重复。各组中华绒螯蟹分别投喂小麦淀粉水平为12.0%、17.0%、22.0%、27.0%、32.0%的配合饵料。试验期60 d。结果显示,中华绒螯蟹肝胰脏和肠道中蛋白酶最适温度均为55℃,肝胰脏和肠道中蛋白酶最适pH值均为6;肝胰脏和肠道中淀粉酶最适温度分别为55、30℃,最适pH值分别为6、7;肝、胰脏和肠道纤维素酶最适温度均为65℃,最适pH值均为5;12%、17%淀粉组肠道蛋白酶比活力显著高于其他3组(P<0.05),17%淀粉组肝胰脏蛋白酶比活力显著高于其他4组(P<0.05);12%淀粉组肠道淀粉酶比活力最低,显著低于其他4组(P<0.05),27%淀粉组肝胰脏淀粉酶比活力最高,显著高于除32%淀粉组以外的其他3组(P<0.05);27%、32%淀粉水平组肠道纤维素酶比活力显著高于其他3组(P<0.05);12%淀粉组肝胰脏纤维素酶比活力最低,显著低于27%淀粉组、32%淀粉组(P<0.05)。研究表明,随着饵料淀粉水平增加,淀粉酶活力呈升高趋势,蛋白酶活力呈下降趋势;中华绒螯蟹通过调节消化酶活力适应饵料组分的变化。

The experiment explored the optimal temperature and pH value of digestive enzymes in liver, pancreas and intestines of Eriocheir sinensis, to study the effect of wheat starch level in the diet on the specific activity of digestive enzymes of Eriocheir sinensis. 300 Eriocheir sinensis with an average weight of(10.0±0.1) g, were randomly divided into five groups, with three replicates in each group. The Eriocheir sinensis in each group were fed with mixed bait with wheat starch levels of 12.0%, 17.0%, 22.0%, 27.0% and 32.0%. The test period was 60 d. The results showed that the optimal temperature of the protease in liver and pancreas and intestine of Eriocheir sinensis was 55 ℃, the optimal pH value of the protease in the hepatopancreas and intestine was 6. The optimum temperature of amylase in hepatopancreas and intestine was 55 ℃ and 30 ℃, and the optimum p H value was 6 and 7, respectively. The optimum temperature of cellulase in liver,pancreas and intestine was 65 ℃, and the optimum p H value was 5. The specific activity of intestinal protease in 12%starch group and 17% starch group was significantly higher than the other three groups(P<0.05), the hepatic trypsin specific activity in 17% starch group was significantly higher than the other four groups(P<0.05). The 12% starch group had the lowest intestinal amylase specific activity, which was significantly lower than the other four groups(P<0.05). The27% starch group had the highest hepatopancreas amylase specific activity, which was significantly higher than the other three groups except the 32% starch group(P<0.05). The specific activity of intestinal cellulase in the 27% starch group and 32% starch group was significantly higher than that of the other three groups(P<0.05). The specific activity of hepatopancreas cellulase in 12% starch group was the lowest, significantly lower than 27% starch group and32% starch group(P<0.05). The experiment indicates that as the level of bait starch increases, the amylase activity shows an upward trend, while the protease activity shows a downward trend. Eriocheir sinensis adapts to the changes in the composition of the food by adjusting the digestive enzyme activity.