State Key Laboratory of Animal Nutrition, Department of Animal Nutrition & Feed Science, College of Animal Science & Technology, China Agricultural University, Haidian District, Beijing, 100193, China.
College of Veterinary Medicine, China Agricultural University, Haidian District, Beijing, 100193, China.
Microb Cell Fact. 2021 Jun 28;20(1):122. doi: 10.1186/s12934-021-01609-z.
The development and utilization of probiotics had many environmental benefits for replacing antibiotics in animal production. Bacteria in the intestinal mucosa have better adhesion to the host intestinal epithelial cells compared to bacteria in the intestinal contents. In this study, lactic acid bacteria were isolated from the intestinal mucosa of broiler chickens and investigated as the substitution to antibiotic in broiler production.
In addition to acid resistance, high temperature resistance, antimicrobial sensitivity tests, and intestinal epithelial cell adhesion, Enterococcus faecium PNC01 (E. faecium PNC01) was showed to be non-cytotoxic to epithelial cells. Draft genome sequence of E. faecium PNC01 predicted that it synthesized bacteriocin to perform probiotic functions and bacteriocin activity assay showed it inhibited Salmonella typhimurium from invading intestinal epithelial cells. Diet supplemented with E. faecium PNC01 increased the ileal villus height and crypt depth in broiler chickens, reduced the relative length of the cecum at day 21, and reduced the relative length of jejunum and ileum at day 42. Diet supplemented with E. faecium PNC01 increased the relative abundance of Firmicutes and Lactobacillus, decreased the relative abundance of Bacteroides in the cecal microbiota.
E. faecium PNC01 replaced antibiotics to reduce the feed conversion rate. Furthermore, E. faecium PNC01 improved intestinal morphology and altered the composition of microbiota in the cecum to reduce feed conversion rate. Thus, it can be used as an alternative for antibiotics in broiler production to avoid the adverse impact of antibiotics by altering the gut microbiota.
益生菌的开发和利用在动物生产中替代抗生素具有许多环境益处。与肠道内容物中的细菌相比，肠道黏膜中的细菌对宿主肠道上皮细胞具有更好的黏附性。在本研究中，从肉鸡肠道黏膜中分离出乳酸菌，并将其作为抗生素在肉鸡生产中的替代品进行研究。
除了耐酸、耐高温、抗菌药敏试验和肠上皮细胞黏附性外，屎肠球菌 PNC01（E. faecium PNC01）对上皮细胞无细胞毒性。E. faecium PNC01 的基因组草图预测它合成细菌素以发挥益生菌功能，细菌素活性测定表明它抑制了鼠伤寒沙门氏菌入侵肠道上皮细胞。日粮中添加 E. faecium PNC01 增加了肉鸡空肠的绒毛高度和隐窝深度，降低了第 21 天盲肠的相对长度，并降低了第 42 天空肠和回肠的相对长度。日粮中添加 E. faecium PNC01 增加了厚壁菌门和乳酸杆菌的相对丰度，降低了盲肠微生物群中拟杆菌的相对丰度。
E. faecium PNC01 替代抗生素可降低饲料转化率。此外，E. faecium PNC01 改善了肠道形态，并改变了盲肠中微生物群的组成，从而降低了饲料转化率。因此，它可以替代抗生素用于肉鸡生产，以避免抗生素对肠道微生物群的不利影响。
