酸化剂和抗生素对黄羽肉鸡回肠黏膜菌群的影响

Effects of Acidifiers and Antibiotics on Ileal Mucosa Microbiota of Yellow-Feathered Broilers

本试验旨在研究饲粮中长期添加酸化剂和亚剂量硫酸新霉素对黄羽肉鸡回肠黏膜菌群动态变化和组成的影响。选择800只1日龄健康岭南黄羽肉鸡,随机分为4个组,每组5个重复,每个重复40只鸡。对照组(A组)饲喂基础饲粮,B、C和D组饲粮分别在基础饲粮中添加0.2%酸化剂Ⅰ、0.3%酸化剂Ⅱ和50 mg/kg硫酸新霉素。试验期42 d。分别于1、7、14、21、28、35和42日龄时,采集肉鸡回肠黏膜并提取细菌DNA,采用聚合酶链式反应(PCR)-变性梯度凝胶电泳(DGGE)技术分析肉鸡回肠黏膜菌群结构,同时应用16S r DNA基因序列技术,建立42日龄肉鸡回肠黏膜细菌16S r DNA的随机克隆文库。动态变化趋势分析发现,4组肉鸡回肠黏膜菌群结构发生变化的程度不同,1~28日龄时4组的动态变化值分别为9%~33%、8%~90%、8%~56%和17%~45%。回肠黏膜细菌随机克隆文库分析发现,A组文库有94个序列,共产生16个OTUs(operational taxonomic units);B组有87个序列,共产生7个OTUs;C组有98个序列,共产生5个OTUs;D组有94个序列,共产生9个OTUs。A和D组乳酸杆菌属(Lactobacillus)所占克隆总数的比例分别为39.36%和50.00%,极显著高于B(6.90%)和C组(10.20%)(P<0.01);A组与其他各组其他菌属的种类与组成比例存在差异,且均未发现与埃希氏菌属(Escherichia)相关序列。由此可知,饲粮中长期添加酸化剂和亚剂量硫酸新霉素会使1~28日龄岭南黄羽肉鸡回肠黏膜菌群结构发生剧烈变化,42日龄肉鸡回肠黏膜菌群的多样性下降,乳酸杆菌属的组成发生改变,这种变化与差异可能是酸化剂与抗生素持续压力的影响所致。

This experiment was conducted to study the effects of dietary long-term supplemented with acidifiers and subclinical doses of neomycin sulfate on the ileal mucosa microbiota composition and dynamic changes of yellow-feathered broilers. Eight hundred 1-day-old healthy Lingnan yellow-feathered broilers were randomly divided into 4 groups with 5 replicates per group and 40 broilers per replicate. Broilers in control group（ group A） were fed a basal diet,and the others in groups B,C and D were fed the basal diets supplemented with 0.2% acidifier Ⅰ,0.3% acidifier Ⅱ and 50 mg/kg neomycin sulfate,respectively. The experiment lasted for42 days. Ileal mucosa of broilers were collected and microbiota DNA were extracted at 1,7,14,21,28,35 and 42 days of age,respectively. Ileal mucosa microbiota structure of broilers were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis（ PCR-DGGE）,and the random clone library of 16 S rDNA of ileal mucosa microbiota of broilers at 42 days of age were established by 16 S rDNA gene sequences technology. The results of dynamic change trend analysis showed that the change degree of ileal mucosa microbiota structure of broilers in 4 groups was different,the dynamic change value at 1 to 28 days of age in 4 groups were 9% to 33%,8% to 90%,8% to 56% and 17% to 45%,respectively. The results of the random clone library of ileum mucosa microbiota analysis showed that 16 operational taxonomic units（ OTUs）（ form94 sequences） were detected in group A,7 OTUs（ form 87 sequences） in group B,5 OTUs（ form 98 sequences）in group C and 9 OTUs（ form 94 sequences） in group D. The proportion of Lactobacillus in the total number of clones in groups A and D was 39. 36% and 50. 00%,which was significantly higher than that in groups B（ 6.90%） and C（ 10.20%）（ P0.01）. The type and composition proportion of other species were different between groups A and the others. In addition,sequence related to Escherichia were not detected in all groups. These results indicate that dietary long-term supplemented with acidifiers and subclinical doses of neomycin sulfate can cause remarkably change of the ileal mucosa microbiota structure of Lingnan yellow-feathered broilers at 1 to 28 days of age,decreasing of the diversity of ileal mucosa microbiota of broilers at 42 days of age,change of the composition of Lactobacillus,and the changes and differences may be caused by the acidifier and antibiotic continuous pressure.