Milk restriction or oligosaccharide supplementation in calves improves compensatory gain and digestive tract development without changing hormone levels

We estimated the effect of oligosaccharide supplementation and feed restriction on calves. The study was divided into two experimental periods of 28 days each with 20 crossbred calves that had initial body weight of 37 Kg and housed in individual pens. The animals were split in four experimental groups: animals fed 6 L milk/day (CON) in the two periods, animals fed milk restricted (3 L milk/day) in the first period and followed by CON feeding in the second period (RES), animals receiving supplementation of 5 g/day of mannanoligosaccharide (MOS) and animals receiving supplementation of 5 g/day mannan and frutoligosaccharide (MFOS). At the end of the study, all the animals were slaughtered. The average weight gain was lower in the restricted group when compared with CON and MFOS groups in the first period (P < 0.05) and there were no difference among the groups in the second period. Animals supplemented with MOS showed a significant increases in jejunal villus height and rumen papillae, which were not observed for MFOS group (P < 0.05) compared with RES and CON groups. There were no difference in ghrelin and leptin levels among treatments during periods 1 and 2 (P > 0.05). Also, the expression of ghrelin receptors in the paraventricular region of the hypothalamus did not differ among groups. We conclude that milk restriction during the first weeks of life in calves resulted in compensatory gain and did not modify the hormonal profile and expression of the ghrelin receptor in the hypothalamus. Moreover, a prebiotic supplementation changed the development of intestinal and ruminal epithelium.

本研究评估了寡糖（oligosaccharide）补充饲喂与限饲对犊牛的影响。实验共设置两个连续的28天实验阶段，纳入20头初始体重为37千克的杂交犊牛，所有个体均采用单栏饲养模式。将受试犊牛分为4个实验组：①对照组（CON）：两个实验阶段均每日饲喂6升牛奶；②限饲组（RES）：第一阶段每日限饲3升牛奶，第二阶段转为对照组饲喂模式；③甘露寡糖（mannanoligosaccharide, MOS）补充组：每日额外补充5克甘露寡糖；④甘露寡糖与果寡糖（frutoligosaccharide, MFOS）补充组：每日额外补充5克甘露寡糖与果寡糖。实验结束后，对所有犊牛进行屠宰处理。第一阶段，限饲组的平均日增重显著低于对照组与MFOS补充组（P < 0.05）；第二阶段各组间无显著统计学差异。与限饲组和对照组相比，MOS补充组犊牛的空肠绒毛高度与瘤胃乳头高度显著升高，而MFOS补充组未观察到该变化（P < 0.05）。两个实验阶段中，各处理组的生长激素释放肽（ghrelin）与瘦素（leptin）水平均无显著差异（P > 0.05）。此外，下丘脑室旁核区域的生长激素释放肽受体表达量在各组间亦无显著差异。综上，犊牛生命早期的限饲可引发补偿性生长，且不会改变其激素谱与下丘脑生长激素释放肽受体的表达水平；此外，益生元（prebiotic）补充饲喂可调控肠道与瘤胃上皮的发育。