复合益生菌发酵饲料工艺优化与饲喂对虾效果的研究

Optimization process of compound probiotic fermented feed and feeding effect on shrimp

中文关键词: 凡纳滨对虾  复合益生菌  发酵饲料  工艺优化  生长性能  生理功效

英文关键词: Litopenaeus vannamei  Probiotic complex  Fermented feed  Growth performance  Physiological efficacy

中文摘要:

      本研究选用从凡纳滨对虾(Litopenaeus vannamei)肠道中筛选出的3株高效益生菌：枯草芽孢杆菌(Bacillus subtilis)、屎肠球菌(Enterococcus faecium)、酿酒酵母(Saccharomyces cerevisiae)作为发酵菌株，利用正交实验优化复合菌株发酵饲料的工艺条件，并探究了发酵饲料对凡纳滨对虾生长性能和消化、免疫功能的影响，旨在提升配合饲料的营养性能，建立对虾饲料发酵技术。结果表明，3株益生菌按1%：1%：1%接种，通过正交实验优化复合益生菌发酵饲料的发酵温度、料水比、发酵时间，获得3个高效发酵饲料(pH最低组、酸溶蛋白最高组、酸性多糖最高组)的工艺条件。3个高效发酵饲料组经28d饲喂实验，凡纳滨对虾的存活率、增重率、特定生长率明显升高。pH最低组、酸溶蛋白最高组饲料转化率显著下降（P < 0.05），低pH组、酸溶蛋白组肝胰腺指数明显升高，而且各发酵饲料组对虾粗脂肪含量无明显差异；与对照组相比，酸性多糖组肝胰腺和肠道蛋白酶、淀粉酶活力显著升高（P < 0.05）；各发酵饲料组血细胞数量、吞噬率表现为酸性多糖组>低pH组>酸溶蛋白组，Pen3、Crustin基因表达明显升高，而肠道Pen3、Crustin、ALF基因表达均显著高于对照组（P < 0.05），各发酵饲料组炎症因子变化不显著。由此可见，通过优化3株益生菌的发酵工艺，获得pH最低组、酸溶蛋白最高组、酸性多糖最高组3种高效的发酵饲料，能明显提高凡纳滨对虾的生长性能和免疫防御水平，经综合评估酸性多糖组可作为凡纳滨对虾最佳的高效发酵饲料。

英文摘要:

      In this study, three efficient probiotic strains, namely Bacillus subtilis, Enterococcus faecium, Saccharomyces cerevisiae, screened from the intestine of Litopenaeus vannamei, were selected as fermentation strains. The study focused on optimizing the process conditions of compound probiotic fermented feed by orthogonal experiments and investigating the effect of growth performance, digestion and immunity function of L. vannamei fed by fermented feeds, which aimed at improving the nutritional performance of the compound feed and establishing the fermentation technology of shrimp feed. The results showed that with the inoculation ratio of the three strains set as 1%: 1%: 1%, the process conditions of three efficient fermented feeds (the lowest pH group, the highest acid soluble protein group and the highest acid polysaccharide group) were obtained by optimizing the fermentation temperature, water ratio and fermentation time through orthogonal experiments. During the 28-day feeding experiment, shrimp fed with the three fermented feed groups exhibited evidently increased survival rate, weight gain rate, specific growth rate. The lowest pH group and the highest acid-soluble protein group had significantly lower feed conversion rates(P < 0.05). The hepatopancreatic index of shrimp in the lowest pH group and the highest acid soluble protein group increased evidently, while there was no significant difference in the crude lipid content in the three fermented feed groups. In addition, the protease activity and amylase activity of hepatopancreas and intestine in the highest acid polysaccharide group were significantly increased(P < 0.05). Compared with the control group, the total haemocytes count and phagocytosis rate were highest in the highest acid polysaccharide group, followed by the lowest pH group and the highest acid-soluble protein group. The gene expression of Pen3 and Crustin in hemocytes increased evidently, while the expression of Pen3, Crustin and ALF increased significantly in intestine(P < 0.05). However, the expression of inflammatory factors did not show significant changes in the three fermented feed groups. In conclusion, three fermented feed groups which were obtained by optimizing the fermentation process of three probiotic strains can significantly improve the growth performance and immune defense level of L. vannamei. After comprehensive evaluation, the acidic polysaccharide group can be used as the best high-efficiency fermentation feed for L. vannamei.