石莼饲料中添加非淀粉多糖酶对黄斑蓝子鱼(Siganus canaliculatus)生长以及肌肉营养成分的影响

为探讨酶制剂是否有助于提高黄斑蓝子鱼(Siganus canaliculatus)对石莼(Ulva pertusa)海藻饲料的消化利用率,在总蛋白水平为32%、总脂肪水平为8%情况下配置6种饲料,其中两个对照组(未添加石莼为C1、添加15%石莼为C2)、4个实验组,饲养黄斑蓝子鱼幼鱼56 d,通过比较鱼的生长性能、消化道消化酶的活性及饲料的表观消化率等,以确定酶制剂的效果及其适宜添加量。结果显示,4种实验饲料养殖的黄斑蓝子鱼在增重率、特定生长率、蛋白质效率等方面均优于C2对照组,与C1对照组无显著差异(T4实验组的蛋白质效率除外)(P0.05)。全鱼生化成分及胃、前肠、肝脏的蛋白酶、淀粉酶和脂肪酶活性在各组之间无显著差异(P0.05)。实验组鱼对饲料中蛋白质的表观消化率显著高于C2对照组(P0.05)。添加石莼组鱼肌肉中除多不饱和脂肪酸18:2n6、20:5n3、22:5n3和必需氨基酸Met、Tyr含量显著降低(P0.05)以及Glu与His氨基酸含量显著升高(P0.05)外,无其他显著变化。结果表明,石莼饲料中添加非淀粉多糖酶可提高黄斑蓝子鱼的生长效果和饲料利用率,且对鱼肉品质无较大影响。

Effects of Non-Starch Polysaccharide Enzymes in Diets with Seaweed Ulva pertusa on Growth, Dietary Apparent Digestibility and Flesh Nutrition Composition of Siganus canaliculatus

In order to evaluate the effects of non-starch polysaccharide （NSP） enzymes in the seaweed Ulva pertusa-containing diets on the feed utilization of Siganus canaliculatus, we prepared six isonitrogenous and isolipid compound diets with 32%crude protein and 8%lipid. Diets without seaweed were used as control diet 1 （C1）;diets that contained 15%seaweed powder were used as control diet 2 （C2）; four other diets that contained 15% seaweed powder together with different levels of non-starch polysaccharide enzyme were used as experimental diets （T1？T4）. S. canaliculatus juveniles were fed with these six diets for 8 weeks. We then compared their growth performance, the activities of digestive enzymes, and the apparent digestibility of nutrients, in order to determine the effects NSP and its optimal amount in the diet. The results showed that the weight gain rate, specific growth rate and protein efficiency rate in Groups T1？T4 were higher than those in Group C2, but displayed no significant difference from Group C1 （except for the protein efficiency in Group T4） （P〉0.05）. All six groups showed no significant differences in the body biochemical composition and activities of digestive enzymes in stomach, foregut and liver that included protease, amylase and lipase （P〉0.05）. The apparent digestibility coefficient of protein and the digestibility of dry matter in Groups T1？T4 were significantly higher than those in Group C2 （P〈0.05）. The whole body composition was similar between the seaweed groups and the control group. In terms of the amino acid and fatty acid composition in the dorsal muscles, seaweed groups showed no significant differences from the control, except that the levels of ALA, EPA, DPA, Tyr and Met in flesh were reduced in the seaweed groups, and the level of His was increased. These results indicated that the addition of NSP enzyme in seaweed-containing diets could improve the growth performance and feed utilization efficiency, and seaweeds in diet have little impac