饲粮菊糖添加水平对肉仔鸡盲肠、直肠菌群结构及主要菌群数量的影响

Effects of Inulin Supplemental Level on Microbial Community Structure and Main Microbial Populations in Cecum and Rectum of Broilers

本试验旨在研究饲粮菊糖添加水平对肉仔鸡盲肠和直肠菌群结构和主要菌群数量的影响。采用单因素完全随机化设计,选用300只1日龄爱拔益加肉仔鸡,随机分成5组,每组6个重复,每个重复10只。5组肉仔鸡分别饲喂在基础饲粮中添加0(对照组)、0.5、1.5、2.5和5.0 g/kg菊糖的试验饲粮。试验期为6周。采用PCR-变性梯度凝胶电泳(DGGE)和定量PCR(q PCR)技术对42日龄肉仔鸡盲肠和直肠菌群结构及主要菌群数量进行测定。结果表明:1)饲粮菊糖添加水平对肉仔鸡盲肠和直肠菌群丰富度、盲肠菌群香农指数以及直肠菌群均匀度均无显著影响(P>0.05),但显著降低了盲肠菌群均匀度和直肠菌群香农指数(P<0.05)。PCRDGGE图谱上部分优势条带序列分析表明,饲粮添加菊糖促进了肉仔鸡盲肠和直肠厚壁菌门(Firmicutes)中产粪甾醇真细菌(Eubacterium coprostanoligenes)、肠单胞球菌(Intestinimonas sp.)和盲肠肠球菌(Enterococcus cecorum)等细菌的增殖。2)饲粮菊糖添加水平显著影响了肉仔鸡盲肠、直肠总细菌和大肠杆菌数量(P<0.05)。二次曲线分析显示,当菊糖添加水平分别为2.71和2.66 g/kg时,盲肠总细菌和大肠杆菌数量最少;与对照组相比,饲粮添加1.5、2.5、5.0 g/kg菊糖显著降低了盲肠乳酸菌数量(P<0.05),饲粮添加0.5 g/kg菊糖显著增加了直肠乳酸菌数量(P<0.05);饲粮添加5.0 g/kg菊糖时肉仔鸡盲肠、直肠双歧杆菌数量及直肠产气荚膜梭菌数量均为最高,且与对照组差异显著(P<0.05)。综上,在本试验条件下,有利于改善肉仔鸡肠道菌群结构和促进有益菌增殖的菊糖添加水平为2.5~5.0 g/kg。

The purpose of this experiment was to study the effects of inulin supplemental level on microbial community structure and main microbial populations in cecum and rectum of broilers. Three hundred 1-day-old Arbor Acres broilers were selected and randomly distributed into five groups with six replicates per group and ten broilers per replicate by single-factor completely random design. Broilers in those five groups were fed a basal diet supplemented with 0 （control group）, 0.5, 1.5, 2.5 and 5.0 g/kg inulin, respectively. The experi- ment lasted for 6 weeks. The microbial community structure and the main microbial populations in cecum and rectum of 42-day-old broilers were measured using the PCR-denaturing gradient gel electrophoresis （DGGE） and quantitative PCR （qPCR） techniques. The results showed as follows ： 1 ） inulin supplemental level had no significant effects on the cecal and rectal microbial richness, the cecal microbial Shannon-Wiener index and the rectal microbial evenness of broilers （P〉0.05）, but significantly decreased the cecal microbial evenness and rectal microbial Shannon-Wiener index （P〈0.05）. Based on the analysis of some dominant bands in PCR- DGGE fingerprint, diet supplemented with inulin promoted the growth of Eubacterium coprostanoligenes, In- testinimonas sp., Enterococcus cecorum and so on from Firmicutes in cecum and rectum of broilers. 2） Diet supplemented with inulin significantly affected the populations of total bacteria and Escherichia coli in cecum and rectum of broilers （P〈0.05）. Quadratic curve analysis showed that the populations of total bacteria and Escherichia coli were the fewest in cecum of broilers when inulin supplemental levels were 2.71 and 2.66 g/kg, respectively. Compared with control group, diet supplemented with 1.5, 2.5 and 5.0 g/kg inulin significantly decreased the population of cecal Lactobacillus （P〈0.05）, while diet supplemented with 0.5 g/kg inulin significantly increased the population of rectal Lactobacillus （P〈 O. 05 ）. The populations of cecal and rectal Bifidobacteria and rectal Clostridium perfringens were the most when diet supplemented with 5.0 g/kg in- ulin, and the differences were significant compared with control group （P〈0.05）. Thus, results from the cur- rent study suggest that supplementation of 2.5 to 5.0 g/kg inulin to basal diet may have the beneficial effects on improving the microbial community and promoting the growth of beneficial bacteria in intestine of broilers un- der this experimental condition.