耐硼赖氨酸芽孢杆菌的保护剂筛选及其对罗非鱼肠道微生物群落的影响

Screening of protectants for Lysinibacillus boronitolerans and its effects on intestinal microbiota of tilapia

本研究目的是为了探究耐硼赖氨酸芽孢杆菌(Lysinibacillus boronitolerans,YS11)的保存条件及其对罗非鱼肠道微生物多样性和丰度的影响,为微生物饲料添加剂的研发提供科学依据。选择海藻糖、乳糖、蔗糖和脱脂奶粉4种保护剂,并通过浓度梯度优化筛选最佳保护剂,结果表明,YS11在10%海藻糖中,干燥后保持较高的存活率。罗非鱼幼苗饲喂菌体发酵液,喂养70 d后,通过高通量测序观察YS11对罗非鱼肠道微生物群落的影响,结果表明,添加YS11的处理改变了罗非鱼肠道微生物群及其多样性,提高罗非鱼肠道中有益菌的丰度,降低某些潜在致病菌的丰度。本研究结果证实,10%海藻糖为最佳冷冻干燥保护剂;耐硼赖氨酸芽孢杆菌能够调节肠道微生物群,促进益生菌生长,抑制病原菌生长。

In order to explore the preservation conditions of Lysinibacillus boronitolerans YS11 and its effect on the diversity and abundance of intestinal microorganisms in tilapia for the research and development of microbial feed additives.Four protectants,i.e.trehalose,lactose,sucrose and skim milk powder,were selected and optimized by concentration gradient.The results confirmed that YS11 maintained a high survival rate after drying in 10%trehalose.Tilapia fingerlings were fed with feeds containing bacterial fermentation broth,and after 70 days of feeding,high-throughput sequencing was performed to observe the effect of the feeds on tilapia intestinal microbial community.The results showed that the feed containing YS11 changed the tilapia gut microbiota and its diversity,increased the abundance of beneficial bacteria in the tilapia gut,and decreased the abundance of some potential pathogenic bacteria.These results confirmed that 10%trehalose was the best freeze-drying protectant.L.boronitolerans can regulate the intestinal microbiota,promote the growth of probiotics,and inhibit the growth of pathogenic bacteria.