产细菌素乳酸菌对肉鸡肠道微生物的结构与功能基因研究

This study was to search for an alternatives of antibiotics for growth-promoting and investigate the modulation of intestinal microbial ecology and functional genes of probiotics and antibiotics in broilers. Lactic acid bacteria (LAB) will be isolated and screened from the intestinal contents and feces of chicken in different rearing style. Some nisin-producing strain were selected by the capacity to inhibit to E. coli and salmonella. The original strain were treated by ultraviolet (UV) or co-cultured with the common pathogenic bacteria for producing nisin. Nisin was purfied and tested in different environment. The suitable additive was investigated for the nisin diets of supplementing with increasing level of nisin in different groups.In second experiment, 720 one-day-old male AA chickens were randomly distributed to four groups: experimental diet supplemented with nisin-producing LAB, Nisin, antibiotics or no additives,resp. At slaughter(14 and 28 days of age), The enzyme activity of duodenum and jejunal contents were analysis, the microbial DNA were exacted from Ileum and cecum by QIAamp DNAStool. The microbial ecology were used phylogentic analysis and taxonomic assignments. The microbial genes were pyrosequenced using 454 GS FLX technology (Roche). The compare of intestinal microbial ecology and functional genes of chicken supplemented different additive were analysis by metagenomes.

为寻求安全高效的肉鸡促生长用的抗生素替代品，并探讨其对肠道菌群结构和功能基因的影响。从不同饲养环境下的鸡肠道内容物及粪便中筛选出抑菌能力强的乳酸菌，经过菌株诱变与驯化筛选出具有高产细菌素的乳酸菌，并对所产生的细菌素进行测定。通过不同剂量添加试验确定对肉鸡的最适添加量。试验二选用720羽AA肉鸡随机分为4个处理，分别饲喂添加有产细菌素的乳酸菌、商用的细菌素、抗生素及不添加为对照的试验日粮，通过测定14和28日龄肉鸡十二指肠、空肠内容物的酶活和营养成分，探讨其对营养物质消化的影响；通过提取回肠和盲肠微生物DNA，分别利用454高通量测序分析其组成结构；利用宏基因组de novo测序分析肠道微生物的结构、微生物的抗菌基因和功能基因差异，探讨其对肠道微生物的结构和功能基因的差异。