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Cattle-yak is a hybrid F1 generation of cattle and yak, which has a history of more than 3000 years and has shown better production performance and higher economic benefits than those of yaks. However, up to now, there has been no study on the transcriptome-wide m6A methylation profile of bovine skeletal muscle and its potential biological function during muscle development. Here, we observed significant changes in the expression levels of muscle-related marker genes and methylation-related enzymes during the development of cattle-yak, and the overall m6A content in the Longissimus dorsi muscle of 18-month-old cattle-yak decreased significantly. A total of 36,602 peaks, 11,223 genes and 8388 lncRNAs were identified in the two groups, including 2989 differential peaks (427 up-regulated peaks and 2562 down-regulated peaks), 1457 differentially expressed genes (833 up-regulated genes and 624 down-regulated genes) and 857 differentially expressed lncRNAs (293 up-regulated lncRNAs and 564 down-regulated lncRNAs). GO and KEGG analysis revealed that they were significantly enriched in some muscle-related pathways (Wnt signaling pathway and MAPK signaling pathway) and high-altitude adaptation-related pathway (HIF-1 signaling pathway). Moreover, m6A abundance was positively correlated with gene expression levels, while it was negatively correlated with lncRNA expression levels. This indicates that m6A modification played an important role in the Longissimus dorsi muscle development of cattle-yak; however, the regulation mechanism of m6A-modified mRNA and lncRNA may be different. This study was the first report of transcriptome-wide m6A-modified mRNAs and lncRNAs atlas in the Longissimus dorsi muscle development of cattle-yak, one which will provide new perspectives for genetic improvement in bovines. [ABSTRACT FROM AUTHOR]

A crude cheese, Qula, which is mainly made up of casein, is a common milk product with local characteristics in northwestern China, such as Gansu, Xinjiang and Tibet. It is made from yak milk with a traditional method: defatting, acidifying, and drying in air (at room temperature). Qula is the raw materials of yak milk casein and collected by factory for further processing. Yak milk casein has been widely used in various fields, such as glues, papermaking, leather, food additives and pharmaceutical applications. However, the traditional process, especially for drying under the sun, can cause severe browning, yellowing and poor quality in Qula. Therefore, hot-air drying method which is based on the evaluation of color quality is adopted in Qula processing. Qula samples were from Gannan city in Gansu Province (Experimental group, 60%-62% moisture was conducted; Control group, 10%-12% moisture was conducted). L*, a*, b* values of dried products were taken as target parameters, and the three factors were scored by the comprehensive evaluation using the data standardization method. According to the central composite experimental design, the response surface methodology (RSM) was adopted to discuss the influence caused by drying temperature, material thickness and wind velocity based on the single factor test of temperature (30, 35, 40, 45, 50 and 55°C), material thickness (6, 8, 10, 12, 14 and 16 mm) and wind velocity (20, 40, 60, 80 and 100 m/min). In addition, the quadratic polynomial regression model was established by SAS software to optimize the drying techniques. The peroxide value (POV), thiobarbituric acid reactive substances (TBARS) and 5-hydroxymethylfurfural (HMF) were measured which are the important indictors of fat oxidation and furanic compound forms as an intermediate product in Maillard reaction. The results showed that the order of significance among three factors were: temperature>wind velocity> material thickness. The optimal parameters of hot-air drying were obtained with a temperature of 41°C, material thickness of 10 mm and wind velocity of 60 m/min, then the largest comprehensive score of 0.9012 was obtained. L* value of Qula by hot-air drying increased by 7.18 (P<0.05), a* and b* values reduced by 1.41 and 10.29, respectively (P<0.01), and the POV, TBARS value and the content of 5-HMF reduced by 1.15 g/100 g, 0.84 mg/kg and 1.973 mg/L, respectively (P<0.01). All in all, the damages which were caused by far oxidation and Maillard reaction can be reduced by this method; meanwhile, the color quality of Qula can be improved dramatically. [ABSTRACT FROM AUTHOR]

Simple Summary: Yak (Bos grunniens) is the most economically and culturally important domestic bovine species adapted to the extreme ecological environment of the Qinghai–Tibetan Plateau (QTP), which provides milk, meat, transportation, fuel (yak dung), and wool for local nomads as well as major sources of income. Calves are an important part of the sustainable development of the yak industry on the QTP, and the quality of calf rearing directly determines the production performance of adult animals. Under the traditional grazing management, late weaning (>180 days) of yak calves seriously affects the improvement of their production performance. A comparative study of fecal microbiota dynamics of yak and cattle (Bos taurus) calves in different months after weaning will help to understand the changes in intestinal microbiota structure, and will aid in in improving growth rate and survivability of early weaned calves. Our research will contribute to the development of appropriate strategies to regulate the gut microbiome and thus improve the growth and health of the grazing ruminants on the QTP. Background: The gut microbiota plays an important role in the health and production of animals. However, little information is available on the dynamic variations and comparison of intestinal microbiota in post-weaning yak calves living on the QTP. Methods: We explored the fecal bacterial microbiota succession of yak calves at different months after early weaning (60 d) compared with cattle calves by 16S rRNA gene amplicon sequencing and functional composition prediction. Results: We found no significant difference in blood biochemical parameters related to glucose and lipid metabolism between yaks and calves in different months after weaning. The core fecal bacterial microbiota from both species of calves was dominated by Ruminococcaceae, Rikenellaceae, and Bacteroidaceae. The fecal microbial community has a great alteration within the time after weaning in both cattle and yak calves, but cattle showed a larger change. After five months, the microbiota achieves a stable and concentrated state. This is also similar to the functional profile. Conclusions: Based on the exploration of dynamic changes in the fecal microbiota at an early stage of life, our results illustrated that there were no negative effects of intestinal microbiota succession on yak calves when early weaning was employed. [ABSTRACT FROM AUTHOR]

In the present study, we report the complete mitochondrial genome of Niangya yak (Bos grunniens) and its phylogenetic inferences. The complete mitochondrial DNA is a circular molecule with 16,322 bp length consisting of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region(D-loop). Both ND6 and 7 tRNAs (tRNA-Pro, tRNA-Glu, tRNA-Tyr, tRNA-Cys, tRNA-Asn, tRNA-Ala and tRNA-Gln) are encoded on the light strand, and the remaining genes are encoded on the heavy strand. The overall nucleotide composition is A(33.73%), T(27.28%), C(25.80%), G(13.19%) respectively. The content of C + G is 38.99%. Given that yak is indispensable for the Tibetan people, it is important to understand the genetic status of the population for further systematic genetics, evolutionary significance and protection of genetic resources. Therefore, to understand the evolutionary history of Niangya yak, the complete mitochondrial genome of Niangya yak was sequenced and compared with the mitochondrial genome of closely related Bos species. [ABSTRACT FROM AUTHOR]