Cui Zhanhong, Wu Shengru, Li Jilan, Yang Qi-En, Chai Shatuo, Wang Lei, Wang Xun, Zhang Xiaowei, Liu Shujie, Yao Junhu
Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China.
College of Animal Science and Technology, Northwest A&F University, Yangling, China.
Front Microbiol. 2020 Jun 4;11:994. doi: 10.3389/fmicb.2020.00994. eCollection 2020.
The present study aims to evaluate the effects of different early weaning paradigms, which supplied with extra alfalfa hay, or starter feeding, or both alfalfa hay and starter feeding, along with the milk replacer, on the gastrointestinal microbial community, growth, and immune performance of yak calves. Twenty 30-day-old male yak calves were randomly assigned to four groups, including the control (CON), alfalfa hay (A), starter feeding (S), and starter plus alfalfa hay (SA) groups. The gastrointestinal microbial colonization, the gastrointestinal development and function, and the growth and immune performance of all the yak calves were separately measured. Supplementation with alfalfa and starter feeding during the pre-weaning period significantly increased body weight, body height, body length, and chest girth. The significantly improved rumen fermentation and promoted intestinal digestion-absorption function in alfalfa and starter feeding groups, including the identified significantly increased concentrations of ruminal total volatile fatty acid (VFA); the significantly increased concentrations and proportions of acetate, butyrate, and isovalerate; the increased α-amylase activities in the duodenum, jejunum, and ileum; the increased papillae length and width of rumen epithelium and rumen wall thickness; and the increased villus height and crypt depth of the duodenum, jejunum, and ileum, could all contribute to promote the growth of calves. These significant improvements on rumen fermentation and intestinal digestion-absorption function could be further attributed to the increased proliferation of starch-decomposing, and cellulose- or hemicellulose-decomposing bacteria identified in the rumen, jejunum, and ileum. Furthermore, based on the expression of intestinal inflammatory cytokines and the rumen epithelial RNA sequencing results, alfalfa supplementation reduced the occurrence of ruminal and intestinal inflammation, whereas starter feeding supplementation was mainly beneficial to the differentiation of immune cells and the improved immune function. Meanwhile, the significantly altered relative abundances of genera in the SA group, including increased relative abundance of , /, and in the rumen and increased relative abundance of , , , and in jejunum, were able to reduce gastrointestinal inflammation and enhance the immune function, which enhanced the immune function of the yak calves fed with alfalfa and starter feeding. Overall, milk replacer supplemented with alfalfa and starter feeding during the pre-weaning period could alter gastrointestinal microbiota and then benefit the gastrointestinal development, digestion-absorption function, growth, and immune performance of the yak calves.
本研究旨在评估不同早期断奶模式对牦牛犊牛胃肠道微生物群落、生长和免疫性能的影响，这些模式包括额外提供苜蓿干草、开食料，或同时提供苜蓿干草和开食料以及代乳粉。将20头30日龄雄性牦牛犊牛随机分为四组，包括对照组（CON）、苜蓿干草组（A）、开食料组（S）和开食料加苜蓿干草组（SA）。分别测定所有牦牛犊牛的胃肠道微生物定植、胃肠道发育和功能以及生长和免疫性能。断奶前期补充苜蓿和开食料显著增加了体重、体高、体长和胸围。苜蓿和开食料组瘤胃发酵显著改善，肠道消化吸收功能增强，包括瘤胃总挥发性脂肪酸（VFA）浓度显著增加；乙酸、丁酸和异戊酸浓度及比例显著增加；十二指肠、空肠和回肠中α-淀粉酶活性增加；瘤胃上皮乳头长度和宽度以及瘤胃壁厚度增加；十二指肠、空肠和回肠绒毛高度和隐窝深度增加，所有这些都有助于促进犊牛生长。瘤胃发酵和肠道消化吸收功能的这些显著改善可进一步归因于瘤胃、空肠和回肠中淀粉分解菌以及纤维素或半纤维素分解菌增殖增加。此外，基于肠道炎性细胞因子的表达和瘤胃上皮RNA测序结果，补充苜蓿可减少瘤胃和肠道炎症的发生，而补充开食料主要有利于免疫细胞的分化和免疫功能的改善。同时，SA组中属的相对丰度显著改变，包括瘤胃中 、 / 和 的相对丰度增加，空肠中 、 、 和 的相对丰度增加，能够减少胃肠道炎症并增强免疫功能，从而增强了饲喂苜蓿和开食料的牦牛犊牛的免疫功能。总体而言，断奶前期补充苜蓿和开食料的代乳粉可改变胃肠道微生物群，进而有利于牦牛犊牛的胃肠道发育、消化吸收功能、生长和免疫性能。
