Zhang Fan, Wang Yue, Wang Hui, Nan Xuemei, Guo Yuming, Xiong Benhai
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Front Microbiol. 2022 Mar 8;13:847488. doi: 10.3389/fmicb.2022.847488. eCollection 2022.
Calcium propionate is one kind of good source for preventing and treating hypocalcemia and ketosis for dairy cows in early lactation. However, little is known about the effects of different feeding levels of calcium propionate on the ruminal bacterial community of early lactation dairy cows. This study aimed to explore the effects of different calcium propionate feeding levels on the ruminal fermentation and bacterial community composition of early lactation dairy cows. Twenty-four multiparous cows were randomly allocated into control (CON), low calcium propionate (LCaP), medium calcium propionate (MCaP), and high calcium propionate (HCaP) groups with six cows per group after calving. The CON group cows were fed the normal total mixed ration (TMR), and the cows of the LCaP, MCaP, and HCaP groups were fed TMR supplemented with 200, 350, and 500 g/day calcium propionate for 35 days after calving, respectively. The rumen fermentation parameters were measured every week, and the ruminal bacterial community composition of the last week was analyzed by 16S rRNA gene sequencing. Under the same diet, the rumen pH showed no difference among the four groups, but the content of microbial crude protein (MCP) and ammonia nitrogen quadratically decreased and linearly increased with calcium propionate supplementation, respectively. The feeding of calcium propionate linearly increased the concentrations of total volatile fatty acid (VFA), acetate, propionate, butyrate, iso-valerate, and valerate in the rumen. In all the treatment groups, , , and were the dominant phyla, and and were the dominant genera in the rumen. Compared with the CON group, the addition of calcium propionate to the early lactation dairy cows quadratically improved the alpha diversity index of Chao1 estimator and observed species, but had little effect on the relative abundance of the major bacterial at phyla and genera level. These results suggested different levels of calcium propionate supplementation improved the rumen fermentation and the ruminal bacterial diversity but had little impact on the major ruminal bacterial community composition of dairy cows in early lactation.
丙酸钙是预防和治疗泌乳早期奶牛低钙血症和酮病的一种良好来源。然而，关于不同饲喂水平的丙酸钙对泌乳早期奶牛瘤胃细菌群落的影响知之甚少。本研究旨在探讨不同丙酸钙饲喂水平对泌乳早期奶牛瘤胃发酵和细菌群落组成的影响。24头经产奶牛在产犊后随机分为对照组（CON）、低丙酸钙组（LCaP）、中丙酸钙组（MCaP）和高丙酸钙组（HCaP），每组6头。CON组奶牛饲喂正常全混合日粮（TMR），LCaP、MCaP和HCaP组奶牛在产犊后分别饲喂添加200、350和500 g/天丙酸钙的TMR，持续35天。每周测量瘤胃发酵参数，并通过16S rRNA基因测序分析最后一周的瘤胃细菌群落组成。在相同日粮条件下，四组之间瘤胃pH值无差异，但微生物粗蛋白（MCP）含量和氨氮含量分别随丙酸钙添加量呈二次方下降和线性增加。丙酸钙的添加使瘤胃中总挥发性脂肪酸（VFA）、乙酸、丙酸、丁酸、异戊酸和戊酸的浓度线性增加。在所有处理组中， 、 和 是瘤胃中的优势菌门， 和 是瘤胃中的优势菌属。与CON组相比，在泌乳早期奶牛日粮中添加丙酸钙可二次方提高Chao1估计器和观测物种的α多样性指数，但对主要细菌在菌门和菌属水平的相对丰度影响较小。这些结果表明，不同水平的丙酸钙添加改善了瘤胃发酵和瘤胃细菌多样性，但对泌乳早期奶牛瘤胃主要细菌群落组成影响较小。
