酵母β-葡聚糖对早期断奶犊牛胃肠道发育的影响

Effects of Yeast β-glucan on Gastrointestinal Development in Early-weaning Calves

本试验在犊牛代乳粉中添加酵母β-葡聚糖,研究其对早期断奶犊牛器官发育、胃肠道形态发育及直肠中微生物数量变化的影响。选取42头新生荷斯坦犊牛,按照日粮中酵母β-葡聚糖添加量不同分为:0(对照组)、25、50、75、100和200 mg/kg 6个组,每组7个重复,每个重复1头牛,试验期56 d。试验结束时屠宰,取瘤胃前背盲囊、十二指肠、空肠和回肠做肠道组织切片,收集直肠内容物经稀释后做微生物计数。结果显示:瘤网胃相对比重有随日粮中酵母β-葡聚糖含量升高而上升的趋势,但差异均不显著(P>0.05);小肠各段绒毛高度与隐窝深度比(V/C)以75 mg/kg组显著大于其余各组(P<0.05),各组直肠内容物中大肠杆菌数以75 mg/kg组显著低于对照组(P<0.05),各组乳酸菌数也以75 mg/kg组显著高于其余各组(P<0.05)。试验结果提示:在早期断奶犊牛日粮中添加75 mg/kg酵母β-葡聚糖可提高早期断奶犊牛的小肠绒毛高度,增加小肠绒毛高度与隐窝深度比,优化肠道微生物结构,从而减少疾病发生,促进犊牛健康生长。

This experiment was conducted to investigate the effects of yeast β-glucan on organ development, gastrointestinal morphological development and quantity of microflora in rectum of early-weaning calves. Forty-two neonatal healthy Holstein calves were randomly allotted to 6 groups with 7 replicates each and 1 calve in each replicate. All calves were fed with diets supplemented with 0 （control group）, 25, 50, 75, 100 and 200 mg/kg yeast β-glucan, respectively. The experiment lasted for 56 days. On day 56, calves were slaughtered, tissues from saccus cranialis, duodenum, jejunum and ileum were obtained and used in tissue slice, and the rectal content were collected and diluted for microorganism counts. The results showed that β-glucan might promote rumen-reticulum growth, however, the differences were not significantly （P〉0.05）; compared with other groups, the ratio of villous height to crypt depth was significantly higher in calves fed diet supplemented with 75 mg/kg β-glucan （P〈0.05） ; when β-glucan supplemented at 75 mg/kg in diet, the number of Escherichia coli in rectum was significantly decreased compared with the control group （P〈0.05）, and the number of Lactobacillus was significantly higher than other groups （P〈0.05）. It was concluded that supplementation of 75 mg/kg β-glucan could increase the height of intestinal villi, the ratio of villous height to crypt depth and adjust the structure of intestinal microflora, thus decreased the incidence of disease and had a health-promoting effect on the growth of claves.