Tropical Feed Resources Research and Development Center (TROFREC), Khon Kaen, 40002, Thailand.
Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand.
Sci Rep. 2021 Mar 18;11(1):6236. doi: 10.1038/s41598-021-85643-2.
Upgrading the nutritive value of rice straw (RS) is necessary to increase its contribution to enhancing meat and milk production. Present work verified whether novel Crabtree negative yeast inoculant could promote RS utilization, rumen fermentation, and milk quality in tropical crossbred lactating Holstein cows. The new stain of Crabtree negative yeasts (Pichia kudriavzevii KKU20 and Candida tropicalis KKU20) was isolated from the rumen of dairy cattle. This study used 6 multiparous crossbreds between Holstein Frisian × Zebu dairy cows in their mid-lactation period. Dairy cows were randomly allocated to three ensiled RS with various yeast stains including Saccharomyces cerevisiae, P. kudriavzevii KKU20, and C. tropicalis KKU20 according to a 3 × 3 replicated Latin square design. Crabtree-negative yeast (P. kudriavzevii and C. tropicalis) increased the apparent digestibility of dry matter by about 6.9% when compared with Crabtree-positive yeast (S. cerevisiae). Bacterial populations were highest with ensiled RS by C. tropicalis KKU20. Ensiled RS with Crabtree-negative yeasts were significantly increased with total volatile fatty acids, but they did not affect volatile fatty acid profiles. Milk protein precentage was highest at 35.6 g/kg when C. tropicalis was fed, and lowest when applied with S. cerevisiae and P. kudriavzevii KKU20 in ensiled RS at 34.5 and 34.1 g/kg, respectively. Thus, feeding ensiled RS with novel Crabtree negative yeast could improve RS digestion, rumen fermentation, and milk protein content in dairy cows.
提高稻草（RS）的营养价值对于提高其在提高肉奶产量方面的贡献是必要的。本研究旨在验证新型克雷伯氏阴性酵母接种剂是否能促进热带杂交泌乳荷斯坦奶牛对 RS 的利用、瘤胃发酵和牛奶质量。新型克雷伯氏阴性酵母（毕赤酵母 KKU20 和热带假丝酵母 KKU20）是从奶牛瘤胃中分离出来的。本研究使用了 6 头处于泌乳中期的荷斯坦弗里生牛与本地牛杂交的奶牛。奶牛随机分配到 3 种不同酵母菌株青贮 RS 中，包括酿酒酵母、毕赤酵母 KKU20 和热带假丝酵母 KKU20，采用 3×3 拉丁方设计。与克雷伯氏阳性酵母（酿酒酵母）相比，克雷伯氏阴性酵母（毕赤酵母和热带假丝酵母）可使干物质表观消化率提高约 6.9%。用 C. tropicalis KKU20 青贮 RS 时细菌数量最高。用克雷伯氏阴性酵母青贮 RS 可显著增加总挥发性脂肪酸，但对挥发性脂肪酸谱没有影响。当添加 C. tropicalis 时，牛奶蛋白百分比最高为 35.6 g/kg，而在添加 S. cerevisiae 和 P. kudriavzevii KKU20 的青贮 RS 中分别为 34.5 和 34.1 g/kg 时最低。因此，饲喂含新型克雷伯氏阴性酵母的青贮 RS 可以提高奶牛对 RS 的消化率、瘤胃发酵和牛奶蛋白含量。
