基于盲肠菌群和回肠粘膜基因表达探讨解淀粉芽孢杆菌提高蛋鸡生产性能的潜在机制

Exploring mechanisms for Bacillus amyloliquefaciens-mediated production performance improvement of laying hens based on cecal microflor and ileum mucosal gene expression

摘要:

【背景】我们的前期工作表明，在蛋鸡饲料中添加解淀粉芽孢杆菌BLCC1-0238可显著提高产蛋性能和蛋品质，但其益生机制还不清楚。【目的】从基因组学和转录组学的视角去揭示益生菌提高蛋鸡生产性能的潜在机制。【方法】利用高通量测序技术比较分析基础日粮组(C组)和解淀粉芽孢杆菌BLCC1-0238添加组(0.06%，2.0×1010 cfu/g，T组)盲肠微生物菌群和回肠粘膜基因表达的差异。【结果】基因组学分析发现，与对照组相比，益生菌添加组的盲肠菌群Chao1和Shannon指数升高；在门水平上，厚壁菌门/拟杆菌门(Firmicutes/Bacteroidetes)的比例显著增加，梭杆菌门(Fusobacteria)和变形菌门(Proteobacteria)的相对丰度降低；在属水平上，厚壁菌门中的考拉杆菌属(Phascolarctobacterium)、乳酸杆菌属(Lactobacillus)、瘤胃球菌科UCG-014属(Ruminococcaceae UCG-014)、厌氧棍状菌属(Anaerotruncus)、瘤胃梭菌属(Ruminiclostridium 9)、克里斯滕森氏菌(Christensenellaceae_R-7_group)相对丰度明显增加。转录组学结果表明，回肠粘膜组织中共有356个差异表达基因，其中，上调基因199个，下调基因157个。生物信息学分析提示，上调基因参与了淀粉和蔗糖代谢、半乳糖代谢以及甘氨酸、丝氨酸和苏氨酸代谢等促进物质代谢和营养吸收的过程。【结论】日粮中添加解淀粉芽孢杆菌BLCC1-0238，可通过改善盲肠菌群多样性和肠道营养吸收能力提高蛋鸡的饲料利用率和产蛋性能，具有潜在的实用价值。

Abstract:

[Background] Bacillus amyloliquefaciens BLCC1-0238 supplementation has been reported to effectively improve production performance and egg quality of laying hens in our previous study, the underlying mechanism, however, remains poorly understood. [Objective] The current study was conducted to examine the potential mechanism of B. amyloliquefaciens BLCC1-0238 to increase production performance of laying hens by evaluating cecal microflora and gene expression in ileum mucosa. [Methods] High-throughput sequencing technology was used to compare the differences of cecal microflora composition and gene transcription level of ileum mucosa between the basal diet group (group C) and B. amyloliquefaciens BLCC1-0238 supplementation group (0.06%, 2.0×1010 cfu/g, group T). [Results] B. amyloliquefaciens BLCC1-0238 supplementation can produce higher indexes of Chao1 and Shannon, which demonstrated increased diversity of cecal microflora. At the phylum level, the ratio of Firmicutes/Bacteroidetes was significantly increased, while relative abundances of Fusobacteria and Proteobacteria were reduced, and at the genus level, the relative abundances of Phascolarctobacterium, Lactobacillus, Ruminococcaceae UCG-014, Anaerotruncus, Ruminiclostridium 9, and Christensenellaceae_R-7_ group were all elevated, which indicated that B. amyloliquefaciens BLCC1-0238 supplementation altered the cecal microflora composition from different levels. With respect to gene expression change in ileum mucosa, 356 differentially expressed genes were identified, among which 199 genes were up-regulated and 157 genes were down-regulated. Bio-informatics analysis found that these up-regulated genes were involved in numerous signaling pathways associated with nutrition metabolism, such as glycine, serine and threonine metabolism, starch and sucrose metabolism, and galactose metabolism, which may accelerate nutrition absorption of laying hens. [Conclusion] B. amyloliquefaciens BLCC1-0238 supplementation can effectively improve laying hen production performance via increasing the diversity of cecal microflora and promoting nutrition absorption of laying hens, providing solid evidence for its further practical application.