Kumar Sandeep, Khan M Ajmal, Beijer Emma, Liu Jinxin, Lowe Katherine K, Young Wayne, Mills David A, Moon Christina D
AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand.
Animal Nutrition Group, Wageningen University and Research, Wageningen, The Netherlands.
Anim Microbiome. 2021 Apr 1;3(1):27. doi: 10.1186/s42523-021-00088-2.
The nutrition of calves from birth until weaning is predominantly from liquid (milk or milk-based) feeds. Liquid feed allowances are often restricted during artificial rearing to accelerate the development of the rumen by promoting solid feed intake. Liquid feeds bypass the rumen and are digested in the lower digestive tract, however, the influence of different types of milk feeds, and their allowances, on the calf hindgut microbiota is not well understood. In this study, faecal samples from 199 calves raised on three different allowances of milk replacer: 10% of initial bodyweight (LA), 20% of initial bodyweight (HA), and ad libitum (ADLIB), were collected just prior to weaning. Bacterial community structures and fermentation products were analysed, and their relationships with calf growth and health parameters were examined to identify potential interactions between diet, gut microbiota and calf performance.
Differences in the total concentrations of short-chain fatty acids were not observed, but higher milk replacer allowances increased the concentrations of branched short-chain fatty acids and decreased acetate to propionate ratios. The bacterial communities were dominated by Ruminococcaceae, Lachnospiraceae and Bacteroides, and the bacterial diversity of the ADLIB diet group was greater than that of the other diet groups. Faecalibacterium was over three times more abundant in the ADLIB compared to the LA group, and its abundance correlated strongly with girth and body weight gains. Milk replacer intake correlated strongly with Peptococcus and Blautia, which also correlated with body weight gain. Bifidobacterium averaged less than 1% abundance, however its levels, and those of Clostridium sensu stricto 1, correlated strongly with initial serum protein levels, which are an indicator of colostrum intake and passive transfer of immunoglobulins in early life.
Higher milk replacer intakes in calves increased hindgut bacterial diversity and resulted in bacterial communities and short chain fatty acid profiles associated with greater protein fermentation. Increased abundances of beneficial bacteria such as Faecalibacterium, were also observed, which may contribute to development and growth. Moreover, correlations between microbial taxa and initial serum protein levels suggest that colostrum intake in the first days of life may influence microbiota composition at pre-weaning.
从出生到断奶期间，犊牛的营养主要来自液体（牛奶或代乳品）饲料。在人工饲养过程中，为了通过促进固体饲料摄入来加速瘤胃发育，通常会限制液体饲料的供应量。液体饲料绕过瘤胃，在消化道下段消化，然而，不同类型的牛奶饲料及其供应量对犊牛后肠道微生物群的影响尚不清楚。在本研究中，采集了199头在三种不同代乳品供应量下饲养的犊牛的粪便样本：初始体重的10%（低供应量组，LA）、初始体重的20%（高供应量组，HA）和自由采食（自由采食组，ADLIB），均在断奶前采集。分析了细菌群落结构和发酵产物，并研究了它们与犊牛生长和健康参数的关系，以确定饮食、肠道微生物群和犊牛性能之间的潜在相互作用。
未观察到短链脂肪酸总浓度的差异，但较高的代乳品供应量增加了支链短链脂肪酸的浓度，并降低了乙酸与丙酸的比例。细菌群落以瘤胃球菌科、毛螺菌科和拟杆菌属为主，自由采食组的细菌多样性高于其他饮食组。与低供应量组相比，自由采食组的粪杆菌丰度高出三倍多，其丰度与胸围和体重增加密切相关。代乳品摄入量与消化球菌属和布劳特氏菌属密切相关，这两种菌也与体重增加相关。双歧杆菌的平均丰度低于1%，但其水平以及严格意义上的梭菌1的水平与初始血清蛋白水平密切相关，初始血清蛋白水平是初乳摄入量和早期免疫球蛋白被动转移的指标。
犊牛较高的代乳品摄入量增加了后肠道细菌多样性，并导致与更多蛋白质发酵相关的细菌群落和短链脂肪酸谱。还观察到有益细菌如粪杆菌的丰度增加，这可能有助于发育和生长。此外，微生物分类群与初始血清蛋白水平之间的相关性表明，出生后最初几天的初乳摄入量可能会影响断奶前的微生物群组成。
