柠檬酸对蛋鸡消化道内容物pH和盲肠菌群的影响

Effects of citric acid on gastrointestinal pH and microflora of laying hens

选择20周龄宝万斯高兰褐蛋鸡810只,进行6处理3重复单因子试验,分别饲喂添加0(对照组), 0．5,1．5．2．5,3．5和5．5 g／kg柠檬酸(CA)的日粮,于试验第1,2,10和15周周末分别从对照组,0．5．2．5和5．5 g／kg CA添加组每重复选取一只鸡宰杀,测定其消化道内容物pH和盲肠菌群数,研究CA对蛋鸡H粮、消化道pH和盲肠微生物菌群的影响。结果表明,添加0．5～5．5 g／kg CA可显著(P<0．05)或极显著(P<0．01)降低日粮pH;5．5 g／kg CA在添加1周时可显著降低肌胃pH(P<0．05),其余添加组鸡肌胃、小肠、盲肠pH无显著差异(P>0．05);添加2．5,5．5 g／kg CA可有效降低盲肠大肠杆菌数,5．5 g／kg CA在添加1周时可显著提高盲肠乳酸杆菌数(P< 0．05),之后这种作用随添加时间的延长而减小。

810 laying hens in 20 week of age were selected to determine the effect of citric acid（CA）on gastrointestinal pH and microflora. In the experiment, six treatments and three replicates design were used, and the levels of CA addition were 0, 0.5, 1.5, 2.5, 3.5 and 5.5 g/kg,respectively. One hen of each replicate was slaughtered at the 1st,2nd, 10th, 15th weekend to measure pH of gizzard, small intestinal, cecum and E. coli and lactobacillus concentration of cecum contents, and diet pH of each treatment were also measured during the trial. The result showed：diet pH decreased significantly by adding 0.5-5.5 g/kg CA （P〈0.05）and decreased extremely significantly by 2. 5-5.5 g/kg CA supplementation（P〈0.05） ; tion at lstweekend （P〈0.05）, no significant effect of CA gizzard pH decreased significantly by 5.5 g/kg CA addicontent on pH of gizzard, small intestinal and cecum was observed at anytime（P〉0.05）. E. coli concentration of cecum contents were lowered with 2. 5,5.5 g/kg diet CA addition supplemente, at 1st weekend （P〈0.05） or 10th weekend（P〈0.05）. The experiment demonstrated that all CA supplementation depressed E. coli extremely significantly at 15th weekend vs control group（P〈0. 05）; compared with the control group, only 5.5 g/kg CA increased the lactobacillus concentration extremely significantly （P〈0.05）at 1st weekend and the effects decreased since then.