饲料中添加两株乳酸菌及其发酵上清液对凡纳滨对虾消化酶活性的影响

Effects of two lactic acid bacteria species and the corresponding supernatants on the activities of digestive enzymes in Litopenaeus vannamei

为了探讨前期实验获得的益生菌及其发酵上清液对凡纳滨对虾消化功能的影响,将初始体质量3.5 g±0.06 g的凡纳滨对虾(Litopenaeus vannamei)在30℃±2℃环境下于水族箱中养殖4周。以基础饲料为对照组,在基础饲料中分别添加戊糖乳杆菌(Lactobacillus pentosus)HC-2、粪肠球菌(Enterococcus faecium)NRW-2、戊糖乳杆菌HC-2的发酵上清液,最终每克基础饲料中含有1.0×107 CFU益生菌或此菌量所对应的发酵上清液,共配制3组实验饲料。实验结果如下:与对照组相比,各实验组对虾肠道中蛋白酶活力显著提高(P<0.05),但肝胰腺中蛋白酶活力无显著差异;添加NRW-2的实验组与对照组相比,肠道和肝胰腺中淀粉酶和脂肪酶活力均显著提高(P<0.05),HC-2组对虾肝胰腺中淀粉酶及肠道中脂肪酶的活力显著提高(P<0.05),而HC-2发酵上清液的添加仅显著提高了对虾肠道蛋白酶和淀粉酶的活性。结果表明饲料中添加NRW-2、HC-2及其发酵上清液可以提高凡纳滨对虾肠道及肝胰腺中消化酶的活力,但在不同组织中提高消化酶活性的种类是不同的,为水产养殖安全投入品的开发及乳酸菌在水产养殖中的推广应用提供一定的科学依据。

To investigate the effects of probiotics and the corresponding supernatants on the activities of digestive enzymes in Litopenaeus vannamei, several groups of L. vannamei（approximately 3.5 g） were reared at a temperature of 30 ± 2°C in an aquaria for 4 weeks. The following four trials（three treated and one control） were conducted： T1, shrimp fed with a commercial diet ＋ strain Lactobacillus pentosus HC-2（1×10^7CFU/g feed）; T2, shrimp fed with a commercial diet ＋ strain Enterococcus faecium NRW-2（1×10^7-CFU/g feed）; T3, shrimp fed with a commercial diet ＋ the supernatant of strain L. pentosus HC-2（the corresponding supernatant of 1×10^7CFU/g feed of L. pentosus HC-2）; and T4, shrimp fed with a commercial diet alone as a control. The results demonstrated that the protease activities were significantly（P〈0.05） increased in the intestines of three treatment groups compared with those in the control group, but they were not significantly increased in the hepatopancreas. The amylase and lipase activities were significantly（P〈0.05） increased in the intestines and hepatopancreas of shrimp fed with E. faecium NRW-2 compared with those in the control group. The amylase and lipase activities were significantly（P〈0.05） increased in the hepatopancreas and intestines, respectively, in the group of shrimp fed with L. pentosus HC-2, whereas the protease and amylase activities were just increased significantly in the intestines of shrimp fed with the supernatant of L. pentosus HC-2. This study suggested that the activities of digestive enzymes in L. vannamei can increase by NRW-2, HC-2, and the corresponding supernatant but vary in different tissues. These results provide a solid foundation for the application of probiotics in aquaculture.