甘露寡糖对肉仔鸡肠道微生物区系发育的影响

Effects of mannose-oligosaccharide on bacterial community of gut in broilers

利用PCR-DGGE技术对肠道细菌16S rDNA的V6-V8可变区进行分析,研究肉仔鸡生长过程中肠道微生物区系的发育规律,并重点探讨日粮中添加甘露寡糖对肉仔鸡肠道菌群稳定性及多样性的影响.选择1日龄健康AA肉仔鸡192羽,随机分为2组,Ⅰ组为对照组（饲喂基础日粮）,Ⅱ组为甘露寡糖（MOS）组（1~21 d：饲喂基础日粮＋0.2%MOS;22~42 d：饲喂基础日粮＋0.1%MOS）,每组4个重复,每个重复24羽.结果表明：肉鸡肠道菌群以乳酸杆菌为主要优势菌群,并且随着日龄变化各消化道的优势菌群发生相应改变;盲肠内菌群的多样性在各日龄段的表现最为丰富,且越接近消化道远端,各日龄间菌群的相似性就越低;日粮中添加MOS增加了肠道中乳酸杆菌等有益菌的数量,并可抑制梭菌属等有害菌的生长,维持肠道健康;同时还发现空白组各日龄肌胃、十二指肠、空肠、回肠和盲肠中菌群相似性最高分别可达77%、68%、72%、49%和63%,MOS组相应的分别为76%、84%、72%、49%和63%,这说明日粮中添加MOS会对肉鸡肠道菌群产生影响,但日龄的变化仍是影响肠道微生物区系的主要因素.

DNA was extracted from the broiler＇s faecal samples and the V6-V8 regions of bacterial 16S rDNA were amplified and analyzed by denaturing gradient gel electrophoresis（DGGE） to monitor the development of bacterial community in faeces of broilers and the effects of mannose-oligosaccharide supplementation on bacterial community of intestinal tract.The broiler chickens were randomly assigned to 2 dietary treatments： Group I（control） was fed corn-soybean meal based diet,and group II was fed basal diet supplemented with 0.2% MOS at 1-21 d and 0.1% MOS at 22-42 d,each of which were assigned to 4 replicates of 24 birds each.Results showed that the major species in gut were Lactobacilli,and each region of the gut developed its own unique microbial profile,and this community became more complex as the chickens grew older.The diversity of the bacterial community in cecum was richer than any others.The similarity of the bacterial community at each age was as low as approaching to the distal gut.The group with MOS enhanced the growth of Lactobacilli in the gut,while inhibited the growth of Clostridium to maintain gut health.It was also found that the highest similarity of the bacterial community of gizzard,duodenum,jejunum,ileum and cecum in control was（group Ⅰ） 77%,68%,72%,49%,63% respectively,while group II was 76%,84%,72%,49%,63% respectively.The results demonstrated that age of chickens had the most profound effect on these characteristics of the microbiota.