Liu Suran, Wei Ziwei, Deng Ming, Xian Zhenyu, Liu Dewu, Liu Guangbin, Li Yaokun, Sun Baoli, Guo Yongqing
Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
Animals (Basel). 2023 Aug 3;13(15):2508. doi: 10.3390/ani13152508.
In this study, changes in milk performance, nutrient digestibility, hindgut fermentation parameters and microflora were observed by inducing milk fat depression (MFD) in dairy cows fed with a high-starch or a high-fat diet. Eight Holstein cows were paired in a completely randomized cross-over design within two 35 d periods (18 d control period and 17d induction period). During the control period, all cows were fed the low-starch and low-fat diet (CON), and at the induction period, four of the cows were fed a high-starch diet with crushed wheat (IS), and the other cows were fed a high-fat diet with sunflower fat (IO). The results showed that, compared to when the cows were fed the CON diet, when cows were fed the IS or IO diet, they had lower milk fat concentrations, energy corrected milk, 3.5% fat-corrected milk yield, feed efficiency and apparent digestibility of NDF and ADF. However, cows fed the IO diet had a lower apparent digestibility of ether extracts. In addition, we observed that when cows were fed the high-starch (IS) or high-fat (IO) diet, they had a higher fecal concentration of propionate and acetate, and a lower NH-N. Compared to when the cows were fed the CON diet, cows fed the IS diet had a lower pH, and cows fed the IO diet had a lower concentration of valerate in feces. In the hindgut microbiota, the relative abundance of Oscillospiraceae_UCG-005 was increased, while the Verrucomicrobiota and Lachnospiraceae_AC2044_group were decreased when cows were fed the IO diet. The relative abundance of Prevotellaceae_UCG-003 was increased, while the Alistipes and Verrucomicrobiota decreased, and the Treponema, Spirochaetota and Lachnospiraceae_AC2044_group showed a decreasing trend when cows were fed the IS diet. In summary, this study suggested that high-starch or high-fat feeding could induce MFD in dairy cows, and the high-fat diet had the greatest effect on milk fat; the high-starch or high-fat diet affected hindgut fermentation and apparent fiber digestibility. The changes in hindgut flora suggested that hindgut microbiota may be associated with MFD in cows.
在本研究中，通过对饲喂高淀粉或高脂肪日粮的奶牛诱导乳脂降低（MFD），观察了其产奶性能、养分消化率、后肠发酵参数和微生物区系的变化。八头荷斯坦奶牛在两个35天周期内采用完全随机交叉设计进行配对（18天对照期和17天诱导期）。在对照期，所有奶牛饲喂低淀粉和低脂肪日粮（CON），在诱导期，四头奶牛饲喂含碎小麦的高淀粉日粮（IS），其他奶牛饲喂含向日葵脂肪的高脂肪日粮（IO）。结果表明，与饲喂CON日粮时相比，奶牛饲喂IS或IO日粮时，乳脂浓度、能量校正乳、3.5%脂肪校正乳产量、饲料效率以及中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）的表观消化率较低。然而，饲喂IO日粮的奶牛乙醚提取物的表观消化率较低。此外，我们观察到，当奶牛饲喂高淀粉（IS）或高脂肪（IO）日粮时，粪便中丙酸和乙酸的浓度较高，而氨态氮（NH-N）较低。与饲喂CON日粮时相比，饲喂IS日粮的奶牛粪便pH较低，饲喂IO日粮的奶牛粪便中戊酸浓度较低。在后肠微生物群中，当奶牛饲喂IO日粮时，颤螺菌科_UCG-005的相对丰度增加，而疣微菌门和毛螺菌科_AC2044_组减少。当奶牛饲喂IS日粮时，普雷沃氏菌科_UCG-003的相对丰度增加，而艾利斯菌属和疣微菌门减少，密螺旋体属、螺旋体门和毛螺菌科_AC2044_组呈下降趋势。总之，本研究表明，高淀粉或高脂肪饲喂可诱导奶牛发生MFD，高脂肪日粮对乳脂的影响最大；高淀粉或高脂肪日粮影响后肠发酵和表观纤维消化率。后肠菌群的变化表明，后肠微生物群可能与奶牛的MFD有关。
