Comparative study of growth performance, blood biochemistry, rumen fermentation, ruminal and fecal bacterial structure between yaks and cattle raised under high concentrate feeding conditions
Compared with native cattle, yaks are more suitable for grazing conditions in the Qinghai-Tibet Plateau in terms of energy acquisition and absorption. However, in order to meet the growing demand of herdsmen for milk and meat, it is very important to explore the metabolism and health status of yaks compared with cattle under the condition of a high-concentrate diet. This study compared growth performance, serum biochemical indicators, rumen fermentation parameters, rumen bacterial structure, and fecal bacterial structure of cattle and yaks, fed for two months, given a feed containing concentrate to roughage ratio of 7: 3 on a dry matter basis. The dry matter intake, daily water intake, average daily gain, and feed to gain ratio of yak are significantly lower than those of cattle (P < 0.050). The serum biochemical results showed that the albumin: globulin ratio, urea, and uric acid in yaks serum were significantly higher than that in cattle (P < 0.050). Aspartate aminotransferase, indirect bilirubin, creatine kinase, lactate dehydrogenase, and total cholesterol were significantly lower in yaks than that in cattle (P < 0.050). Rumen pH, acetate to propionate ratio, and acetate were lower in yaks than in cattle while the lactate in yaks was higher than in cattle (P < 0.050). There were significant differences in the structure of ruminal bacteria between cattle and yaks. The relative abundance of Prevotella 1, Treponema 2, and Ruminococcus 1 at the genus level were significantly lower than that of cattle (P < 0.050), while the relative abundance of Quinella, Unclassified Bacteroides BS11 gut group, Villonellaceae UCG-001, Bacteroides BS11 gut group, Uncultured-Bacteroidales BS11 gut group were significantly higher than that of cattle (P < 0.050). The prediction of rumen bacterial function showed that there was the metabolic difference between cattle and yaks. In general, the metabolic pathway of cattle was mainly riched in the de novo synthesis of nucleotides, while that of yaks was mainly riched in the metabolic utilization of nutrients. This study provides a basis for understanding the rumen ecology under the condition of a highly concentrated diet.