摘要
The composition of milk replacer (MR) for calves greatly differs from that of bovine whole milk, which may affect gastrointestinal development of young calves. In this light, the objective of the current study was to compare gastrointestinal tract structure and function in response to feeding liquid diets having a same macronutrient profile (e.g., fat, lactose, protein) in calves in the first month of life. Eighteen male Holstein calves (46.6 ± 5.12 kg; 1.4 ± 0.50 d of age at arrival; mean ± standard deviation) were housed individually. Upon arrival, calves were blocked based on age and arrival day, and, within a block, calves were randomly assigned to either a whole milk powder (WP; 26% fat, DM basis, n = 9) or a MR high in fat (25% fat, n = 9) fed 3.0 L 3 times daily (9 L total per day) at 135 g/L through teat buckets. On d 21, gut permeability was assessed with indigestible permeability markers [chromium (Cr)-EDTA, lactulose, and d-mannitol]. On d 32 after arrival, calves were slaughtered. The weight of the total forestomach without contents was greater in WP-fed calves. Furthermore, duodenum and ileum weights were similar between treatment groups, but jejunum and total small intestine weights were greater in WP-fed calves. The surface area of the duodenum and ileum did not differ between treatment groups, but the surface area of the proximal jejunum was greater in calves fed WP. Urinary lactulose and Cr-EDTA recoveries were greater in calves fed WP in the first 6 h post marker administration. Tight junction protein gene expression in the proximal jejunum or ileum did not differ between treatments. The free fatty acid and phospholipid fatty acid profiles in the proximal jejunum and ileum differed between treatments and generally reflected the fatty acid profile of each liquid diet. Feeding WP or MR altered gut permeability and fatty acid composition of the gastrointestinal tract and further investigation are needed to understand the biological relevance of the observed differences.
摘要译文
牛奶替代品（MR）的组成与牛全脂牛奶的组成可能会影响幼体的胃肠道发育。从这个角度来看，当前研究的目的是比较胃肠道结构和功能，以响应在生命的第一个月中具有相同大量营养素特征（例如脂肪，乳糖，蛋白质）的液体饮食（例如脂肪，乳糖，蛋白质）。单独容纳十八个雄性荷斯坦犊牛（46.6±5.12 kg；到达时年龄1.4±0.50 d；平均值±标准偏差）。到达后，根据年龄和到达日对犊牛进行阻塞，在一个街区内，犊牛被随机分配给全牛奶粉（WP； 26％脂肪，DM，n = 9）或脂肪高的MR（25％的脂肪，n = 9）每天3.0升3次（每天9升总计）135 g/l通过质水桶。在D 21上，用不可消化的渗透率标记（CROMIUM（CR）-EDTA，乳乳糖和D-甘露醇）评估肠道渗透率。到达32 D时，小牛被屠杀。在WP喂养的小牛中，没有含量的总弗林卡的重量更大。此外，治疗组之间的十二指肠和回肠重量相似，但是在WP喂养的犊牛中空肠和总小肠重量更大。在治疗组之间，十二指肠和回肠的表面积没有差异，但是在饲养的WP的犊牛中，空肠近端的表面积更大。标记后的前6小时，尿液中的尿乳糖和CR-EDTA回收率更大。处理近端或回肠中的紧密连接蛋白基因表达在治疗之间没有差异。近端空肠和回肠中的游离脂肪酸和磷脂脂肪酸谱在处理之间有所不同，并且通常反映了每种液体饮食的脂肪酸谱。需要喂食WP或MR改变胃肠道的肠道通透性和脂肪酸组成，并需要进一步研究，以了解观察到的差异的生物学相关性。
S.C. Mellors; J.N. Wilms; A.C. Welboren; M.H. Ghaffari; ... M.A. Steele. Gastrointestinal structure and function of preweaning dairy calves fed a whole milk powder or a milk replacer high in fat[J]. Journal of Dairy Science, 2023,106(4): 2408-2427