Study on the microbial diversity of fecal in high and low altitude Yak based on high-throughput sequencing of the 16S ribosomal DNA gene

Yak (Bos grunniens) is a unique cattle species in the alpine region, and is also one of the main herbivorous ruminant cattle species in China, mainly produced in the region above 3000m above the altitude of the Qinghai-Tibet Plateau. Altitude is a restriction condition of ecological environment. With the vertical climate formed by the vertical elevation of the plateau, various organisms changed accordingly. Yaks adapted to harsh natural conditions due to their strong digestibility of crude fiber, their resistance to hunger and hypoxia. Yak has a variety of economic uses and can produce milk, meat, velvet and skin with unique flavor and good quality. Yak products from the plateau region are gradually favored by people because of their pollution-free characteristics).The fecal tract of yak is the main place for its digestion and absorption of nutrients, which is directly related to the nutrition and health of yak. There are a large number of symbiotic bacteria in yak intestines, which can further decompose food residues and plant fibers and promote the absorption of nutrients by yak. Diarrhea is the most common disease in cattle. In recent years, the diarrhea of yak calves, especially yak calves on Qinghai-Tibet plateau, has been more serious. Previously, the yak parasitic disease, a lot of research on bacterial and viral disease, many researchers found that fecal flora by producing vitamins and energy to influence host nutrients, hormones and microbial synthesis and metabolism, and removal of drugs and toxic metabolite, promote the growth of host immune cells and mature to resist the invasion of pathogens. It has not been reported whether diarrhea is caused by the difference of microbial population structure in yak feces. However, in the high and low altitude areas, the environmental climate, air oxygen content and diet of yak are greatly different. Whether these factors induced by altitude will lead to the difference in the microbial population structure of yak feces needs to be further study. In this paper, 16S rDNA sequencing was conducted on the microbes in yak feces based on altitude and diarrhea.