Zhang Fan, Zhao Yiguang, Wang Yue, Wang Hui, Nan Xuemei, Guo Yuming, Xiong Benhai
State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, 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 Vet Sci. 2022 Jul 26;9:940216. doi: 10.3389/fvets.2022.940216. eCollection 2022.
Dietary supplementation with calcium propionate can effectively alleviate negative energy balance and hypocalcemia of dairy cows in early lactation. The objective of this study was to investigate the effects of calcium propionate feeding levels on the immune function, liver function, and fecal microbial composition of dairy cows in early lactation. Thirty-two multiparous Holstein cows were randomly assigned to four treatments after calving. Treatments were a basal diet plus 0, 200, 350, and 500 g calcium propionate per cow per day throughout a 5-week trial period. Cows were milked three times a day, and blood was sampled to measure immune function and liver function on d 7, 21, and 35. The rectal contents were sampled and collected on d 35 to analyze the microbial composition using 16S rRNA gene sequencing. The results indicated that increasing amounts of calcium propionate did not affected the serum concentrations of total protein, IgG, IgM, and calcium, but the concentrations of albumin and IgA changed quadratically. With the increase of calcium propionate, the activity of serum alanine transaminase and aspartate aminotransferase increased linearly, in contrast, the activity of alkaline phosphatase decreased linearly. Moreover, dietary supplementation with increasing levels of calcium propionate tended to quadratically decrease the relative abundance of while quadratically increased the abundance of , and consequently linearly decreased the / ratio in the rectal microbiota. Additionally, the supplementation of calcium propionate increased the relative abundances of and linearly, and quadratically, but decreased the relative abundances of and quadratically. Compared with the CON group, the calcium propionate supplementation significantly decreased the relative abundance of but increased the abundances of and . In summary, these results suggested that the supplementation of calcium propionate to dairy cows in early lactation could beneficially alter the rectal microbiota.
丙酸钙膳食补充剂可有效缓解泌乳早期奶牛的负能量平衡和低钙血症。本研究的目的是调查丙酸钙饲喂水平对泌乳早期奶牛免疫功能、肝功能和粪便微生物组成的影响。32头经产荷斯坦奶牛在产犊后随机分为4组。在为期5周的试验期内，处理方式为基础日粮加每头奶牛每天0、200、350和500克丙酸钙。奶牛每天挤奶3次，并在第7、21和35天采集血液样本以测量免疫功能和肝功能。在第35天采集直肠内容物样本，使用16S rRNA基因测序分析微生物组成。结果表明，丙酸钙添加量增加并未影响血清总蛋白、IgG、IgM和钙的浓度，但白蛋白和IgA的浓度呈二次变化。随着丙酸钙添加量的增加，血清谷丙转氨酶和谷草转氨酶的活性呈线性增加，相反，碱性磷酸酶的活性呈线性下降。此外，随着丙酸钙添加水平的增加，直肠微生物群中的相对丰度呈二次下降，而 的丰度呈二次增加，因此 / 比值呈线性下降。此外，丙酸钙补充剂使 和 的相对丰度呈线性增加， 呈二次增加，但使 和 的相对丰度呈二次下降。与对照组相比（CON组），丙酸钙补充剂显著降低了 的相对丰度，但增加了 和 的丰度。总之，这些结果表明，在泌乳早期给奶牛补充丙酸钙可有益地改变直肠微生物群。
