饲喂酸化乳对犊牛粪便微生物多样性的影响

Effects of Feeding Acidified Milk on Fecal Microbial Diversity of Calves

本试验旨在研究饲喂酸化乳对犊牛粪便微生物多样性的影响。采用完全随机试验设计,选用某规模化奶牛场体高和体重相近的健康荷斯坦新生母犊牛10头,随机分为2个处理(每个处理5头),分别饲喂巴氏杀菌乳和酸化乳,试验期90 d,其中哺乳期60 d。每日记录粪便评分,并计算腹泻率。分别在试验第50和90天时,采集每个处理5头犊牛直肠末端粪样约20 g,根据处理和取样时间分为4组[PB组(巴氏杀菌乳处理第50天样品)、PP组(巴氏杀菌乳处理第90天样品)、AB组(酸化乳处理第50天样品)、AP组(酸化乳处理第90天样品)],进行16S rDNA扩增及测序。结果显示:1)哺乳期内不同日龄阶段,饲喂酸化乳犊牛的粪便评分及腹泻率均显著或极显著低于饲喂巴氏杀菌乳犊牛(P<0.05或P<0.01)。2)共获得可用于后续分析的Tags序列1227017条。按组别进行操作分类单元(OTU)聚类分析,饲喂酸化乳犊牛粪便中特有OTU数均低于饲喂巴氏杀菌乳犊牛。3)4组样本中相对丰度最高的菌门均为厚壁菌门(Firmicutes),其次是拟杆菌门(Bacteroidetes)和梭杆菌门(Fusobacteria)。4)LEfSe分析结果显示,AB组较其他3组具有显著性差异的物种有拟杆菌科(Bacteroidaceae)、拟杆菌属(Bacte roides)、栖粪杆菌属(Faecalibacterium)、瘤胃梭菌属_9(Ruminiclostridium_9)、拟普雷沃菌属(Alloprevotella)、毛螺旋菌科UCG 004属(Lachnospiraceae_UCG 004)、毛螺旋菌科UCG 010属(Lachnospiraceae_UCG 010)、芽孢杆菌纲(Bacill)、乳杆菌目(Lactobacillales)、布劳特氏菌属(Blautia),其中影响最大的为Bacteroidaceae和Bacteroides。综上所述,饲喂酸化乳可降低犊牛腹泻率,改善粪便评分,并可对犊牛肠道菌群平衡产生一定的调节作用。

This experiment was conducted to study the effects of feeding acidified milk on fecal microbial di versity of calves.A completely randomized trial design was used in this experiment.Ten healthy Holstein new born female calves with similar height and body weight were selected from a large scale dairy farm.They were randomly divided into 2 treatments with 5 calves in each treatment,and were fed pasteurized milk and acidified milk,respectively.The experiment lasted for 180 days,including 60 days of lactation.Fecal score was recor ded daily and diarrhea rate was calculated.In addition,about 20 g of fecal samples were taken from the end of calf’s rectum for 16S rDNA amplification and sequencing at days 50 and 90,and the samples were divided in to 4 groups according to treatment and sampling time,which were PB group(samples form pasteurized milk treatment at day 50),PP group(samples form pasteurized milk treatment at day 90),AB group(samples form acidified milk treatment at day 50)and AP group(samples form acidified milk treatment at day 90).The results showed as follows:1)at different age stages during lactation period,the fecal score and the diarrhea rate of calves fed acidified milk were significantly lower than those fed pasteurized milk(P<0.05 or P<0.01).2)A total of 1227017 Tags could be used for subsequent analysis.Operational taxonomic unit(OUT)cluster analysis by each group showed that the number of specific OTU in the feces of calves fed acidified milk were lower than those fed pasteurized milk.3)The highest relative abundance of bacteria in samples of 4 groups was Firmicutes,followed by Bacteroidetes and Fusobacteria.4)The LEfSe analysis result showed that species with significant differences in the AB group compared with other groups were Bacteroidaceae,Bacteroides,Faecal ibacterium,Ruminiclostridium_9,Alloprevotella,Lachnospiraceae_UCG 004,Lachnospiraceae_UCG 010,Bacill,Lactobacillales,Blautia,and the most influential species were Bacteroidaceae and Bacteroides.In sum mary,feeding acidified milk can reduce the diarrhea rate,improve the fecal score,and can also regulate the balance of intestinal flora of calves to a certain degree.