Performance of calves receiving probiotic containing “Bacillus subtilis” and “Bacillus licheniformis”

SUMMARY Twenty-four Holstein calves were utilized and received 4L/d of liquid diet consisting of commercial milk replacer, and had free access to water and starter concentrate. Weaning occurred at the 8th week of age. Animals were distributed in a randomized block design, in the following treatments: 1) Control - without supplementation with probiotic, 2) Supplementation: 2g/d of Bacillus subtilis and Bacillus licheniformis, via milk replacer. Every week calves were weighted and body measurements were taken. Blood samples were drawn weekly for determination of hematocrit, glucose, total protein, urea and albumin. Fecal samples were weekly collected for lactic acid bacteria, enterobacteria couting and fecal pH determination. Concentrate starter intake and fecal scores were monitored daily. Body weight, average daily gain, and corporal measurements were not affected by the supplementation of probiotic; however, presented a significant age effect. The fecal score, fecal pH and starter intake were not affected by probiotic supplementation. However, starter intake and fecal pH were affected by age due to calves’ natural growth. The acid lactic bacteria count was higher than the count of enterobacteria during the whole evaluation period. Only enterobacteria were affected by the age of animals, while acid lactic bacteria remained constant despite little variations. Blood parameters were also not affect by supplementation of probiotic, but all of them, except albumin concentrations, were influenced by age. The supplementation with probiotic containing Bacillus subtilis and Bacillus licheniformis via milk replacer presented no benefits in dairy calves performance or metabolism and did not reduced the occurrence of diarrhea.研究摘要：本试验选用24头荷斯坦犊牛（Holstein calves），每日饲喂4L由商品代乳粉配制的液态日粮，自由饮水并自由采食开食精料，于8周龄时实施断奶。试验采用随机区组设计，设置2个处理组：1）对照组：不添加益生菌（probiotic）；2）益生菌添加组：通过代乳粉每日添加2g枯草芽孢杆菌（Bacillus subtilis）与地衣芽孢杆菌（Bacillus licheniformis）。试验期间每周对犊牛称重并开展体尺测量，每周采集血样以测定红细胞压积（hematocrit）、葡萄糖（glucose）、总蛋白（total protein）、尿素（urea）及白蛋白（albumin）水平，每周采集粪便样品以进行乳酸菌（lactic acid bacteria）计数、肠杆菌科细菌（enterobacteria）计数及粪便pH值测定；每日监测开食精料采食量与粪便评分。结果显示，益生菌添加对犊牛体重、平均日增重及体尺测量指标无显著影响，但上述指标存在显著的年龄效应；粪便评分、粪便pH值及开食精料采食量不受益生菌添加的影响，但开食精料采食量与粪便pH值会随犊牛自然生长的年龄效应产生显著变化。整个试验周期内，乳酸菌计数均高于肠杆菌科细菌计数；仅肠杆菌科细菌计数受动物年龄影响，乳酸菌计数虽存在小幅波动但整体保持稳定。血液参数同样不受益生菌添加的影响，但除白蛋白浓度外，其余血液参数均受年龄的显著影响。综上，通过代乳粉添加含有枯草芽孢杆菌与地衣芽孢杆菌的益生菌制剂，对荷斯坦犊牛的生产性能或代谢无增益效果，亦未降低腹泻发生率。