This experiment aimed to investigate the genetic polymorphism and tissue expression characteristics of the actin-like protein 8 (ACTL8) gene and its association with growth traits in Qinghai Plateau yaks. Using healthy adult yaks as subjects, key regions of the ACTL8 gene were captured via Fast Target sequencing technology, and single nucleotide polymorphism (SNP) loci were screened through high-throughput sequencing for population genetic analysis. The gene expression profile in multiple tissues (including heart, liver, spleen, lung, kidney, muscle and pericardial fat, intermuscular fat, subcutaneous fat, perirenal fat, and intestinal fat) was detected by quantitative real-time PCR (RT-qPCR). Furthermore, the correlation between SNP loci and growth traits such as body weight, body height, body length, and chest circumference was analyzed. The results revealed eight SNP loci in the ACTL8 gene. Tissue expression analysis showed that ACTL8 was the most highly expressed in the liver and subcutaneous fat, with the lowest expression in the kidney. Association analysis indicated that the g.77598 G>A locus was significantly correlated with multiple growth traits. The individuals with GG and AA genotypes had significantly higher body height than those with the GA genotype (P<0.05), and their weight and chest circumference were extremely better than those of the GA genotype individuals (P<0.01). The study demonstrates that the ACTL8 gene exhibits rich genetic diversity in Qinghai Plateau yaks and is highly expressed in key metabolic tissues such as the liver and fat. The key locus g.77598 G>A is highly associated with body height, body weight, and chest circumference, suggesting its potential as a molecular marker for regulating growth efficiency in yaks.

The study aimed to investigate the impact of the feed concentrate to roughage ratio transition on the microbial distribution and functions in yak feces. Twenty-four healthy male yaks at three years old with similar weight were fed a diet of 30∶70 for 1~60 days (Group C30 ), and converted to a diet of 70∶30 for 61~120 days (Group C70 ). The pre-test period was 15 days, and the formal test period was 120 days. Fecal samples were collected using the rectal fecal sampling method from six randomly selected yaks on day 60 and day 120 after feeding for 3~4 hours. The samples were sequenced using 16S rRNA gene sequencing technology to compare and analyze the fecal microbial community, and functional predictions were made using PICRUSt2. The results showed no significant differences in lineage diversity and diversity indices between the two groups (P>0.05). PCoA analysis revealed a significant difference in the composition of fecal microbial communities between the two groups (P<0.05). At the phylum level, the relative abundance of Actinobacteriota in Group C70 was significantly higher than in Group C30 (P<0.05). At the genus level, the relative abundance of unidentified taxa in Group C70 was extremely higher than in Group C30 (P<0.01), and the relative abundance of uncultured bacterium and Roseburia was significantly higher in Group C70 than in Group C30 (P<0.05), while the relative abundance of Lachnospiraceae_NK3A20_group, Olsenella, and Paeniclostridium was significantly higher in Group C30 than in Group C70 (P<0.05). At the KEGG level 2, the expression levels of functions such as energy metabolism, terpenoid and polyketide metabolism, interspecies biodegradation, and metabolism were lower in Group C70 compared to Group C30. The study indicates that the transition of feed concentrate to roughage ratio affects the richness and diversity of fecal microbial communities, significantly influencing the composition of microbial communities in yak feces. Transitioning from a low concentrate to roughage ratio to a high ratio reduces the relative abundance of fiber-degrading bacteria in the hindgut, promotes the proliferation of acid-producing bacteria, increases the proportion of Paeniclostridium.

Yak (Bos grunniens) is a unique livestock animal originating from the Qinghai-Tibet Plateau in China. In the current study, we investigated the maternal genetic diversity, differentiation and phylogeny of wild yak population and four domestic yak breeds (Qinghai-Gaoyuan, Huanhu, Xueduo, and Yushu) in Qinghai, China by analyzing 166 mitochondrial cytochrome b (Cytb) gene sequence variations. Our results indicated that the haplotype and nucleotide diversities of wild yak were 0.883±0.044 and 0.004±0.002, while the total haplotype and nucleotide diversities of four Qinghai domestic yak breeds were 0.646±0.040 and 0.003±0.001, respectively. Among the four Qinghai domestic yak breeds, the haplotype diversity was found to be highest in Yushu yak breed (Hd = 0.770±0.053), while the lowest was recorded in Huanhu yak breed (Hd = 0.501±0.088). Estimates of FST values showed a moderate genetic differentiation between wild yak and Huanhu yak (FST = 0.058) as well as that between Huanhu yak and Yushu yak breeds (FST = 0.052), but a weak genetic differentiation was observed between the other yak breeds/populations (-0.021＜FST＜0.037). Additionally, the clustering analysis based on RST values showed that Xueduo yak and Huanhu yak were clustered into one group, and each of the other three yak breeds/populations was separated into one group, respectively. Overall, the clustering relationship between wild yak and Yushu yak was closer. Maternal phylogenetic analysis showed that wild yak and four local yak breeds/populations in Qinghai represented in three maternal lineages (Mt-Ⅰ, Mt-Ⅱ, and Mt-Ⅲ), indicating three maternal origins in yak. Our study would provide valuable information for the conservation and utilization of wild yak and Qinghai domestic yak breeds.

Fermented feed is rich in probiotics, organic acids and other components, which is easy to digest and absorb by animals, and has high nutritional value. The palatability of the fermented feed is good, with a low content of anti-nutrient factors. It can improve the digestibility and utilization rate of animal feed, stabilize the structure of animal intestinal microorganisms, and enhance the immunity of the body. The paper mainly elaborates the concept and action mechanism of the fermented feed, reviews the effects of the fermented feed on the intestinal health, feed utilization rate, feeding cost and animal production performance, analyzes the problems existing in the application of the fermented feed in animal production, and prospects the future application of the fermented feed, in order to provide reference for the efficient utilization of fermented feed in animal breeding.

A relatively stable microbial ecological balance system in the rumen plays an important role in rumen environment stability and ruminant health maintenance. No studies have reported how rumen fluid transplantation (RFT) affects the composition of rumen microorganisms and yak growth performance. In this experiment, we transplanted fresh rumen fluid adapted to house-feeding yaks to yaks transitioned from natural pastures to house-feeding periods to investigate the effects of rumen fluid transplantation on rumen microbial community regulation and production performance. Twenty yaks were randomly divided into the control group (CON; n = 10) and the rumen fluid transplantation group (RT; n = 10). Ten yaks that had been adapted to stall fattening feed in one month were selected as the rumen fluid donor group to provide fresh rumen fluid. Ruminal fluid transplantation trials were conducted on the 1st, 3rd, and 5th. Overall, 1 L of ruminal fluid was transplanted to each yak in the RT and CON group. The formal trial then began with both groups fed the same diet. After this, growth performance was measured, rumen fluid was collected, and rumen microbial composition was compared using 16s rRNA sequencing data. The results showed that rumen fluid transplantation had no significant effect on yak total weight gain or daily weight gain (p > 0.05), and feed efficiency was higher in the RT group than in the CON group at 3 months (treatment × month: p < 0.01). Ruminal fluid transplantation significantly affected rumen alpha diversity (p < 0.05). Up to day 60, the RT group had significantly higher OTU numbers, Shannon diversity, and Simpson homogeneity than the CON group. Principal coordinate analysis showed that the rumen microbiota differed significantly on days 4 and 7 (p < 0.05). Bacteroidota, Firmicutes, Proteobacteria, and Spirochaetes were the most abundant phyla in the rumen. The relative abundances of Bacteroidota, Proteobacteria, and Spirochaetes were lower in the RT group than in the CON group, with a decrease observed in Bacteroidota in the RT group on days 7 and 28 after rumen fluid transplantation (p = 0.013), while Proteobacteria showed a decreasing trend in the CON group and an increasing trend in RT; however, this was only at day 4 (p = 0.019). The relative abundance of Firmicutes was significantly higher in the RT group than in the CON group on days 4, 7, and 28 (p = 0.001). Prevotella and Rikenellaceae_RC9_gut_group were the predominant genera. In conclusion, our findings suggest that rumen fluid transplantation improves yak growth performance and rumen microbial reshaping. The findings of this study provide new insights into yak microbial community transplantation and a reference for improving feed efficiency in the yak industry.

牦牛奶是一种青藏高原牦牛产出的稀缺畜产品.随着乡村振兴战略的实施,牧区逐渐重视对牦牛奶资源的开发利用,部分主产区已经形成了牦牛奶的收购、加工和销售的产业化发展模式,尽管牦牛奶产业在发展过程中存在一些问题,但是牦牛奶产业已经呈现出欣欣向荣的发展趋势.本文针对牦牛奶产业发展现状和存在的问题及推进牦牛产业发展的政策措施和建议进行概述.

研究旨在为青海省秸秆资源的合理利用提供参考,对当地主要农作物秸秆资源饲料化利用潜力进行系统分析.结果显示:2015-2021年青海省主要农作物可收集秸秆量166.08万～172.30万t,粗蛋白(CP)产出6.15万～6.83万t,代谢能(ME)产出948.73～984.16 GJ.可利用秸秆数量载畜量342.12万～354.93万羊单位,可消化粗蛋白质(DCP)载畜量98.98万～109.87万羊单位,ME载畜量310.18万～321.76万羊单位,间接节粮172.82万～179.32万t,秸秆产肉潜力达8.73万～9.06万t.2020年青海省秸秆节粮数量相当于当年增加小麦种植面积43.55万hm2,秸秆养畜产肉量占当年牛羊肉总产量的26.79％.研究表明,青海省秸秆资源具有饲料化利用潜力,可为青海绿色有机农畜产品输出地建设提供物质资源.

本文概述了青海省现有的各类牦牛品种(资源),通过总结其外貌特征、品种选育和生产性能,为今后牦牛的选育、繁殖及生产提供参考,为牦牛产业的发展提供基础.

Ruminal microflora is closely correlated with the ruminant's diet. However, information regarding the effect of high concentrate diets on rumen microflora in yaks is lacking. In the current study, 24 healthy male yaks were randomly assigned to two groups, each fed with different diets: less concentrate (LC; concentrate: coarse = 40: 60) and high concentrate (HC; concentrate: coarse = 80: 20) diets. Subsequently, a 21-day feeding trial was performed with the yaks, and rumen fluid samples were collected and compared using 16 s rRNA sequencing. The results showed that NH3-N, total VFA, acetate, butyrate, isobutyrate, and isovalerate were significantly higher in the HC group than that in the LC group (p < 0.05), while microbial diversity and richness were significantly lower in the HC group (p < 0.05). Principal coordinate analysis indicated that rumen microflora was significantly different in LC and HC groups (p < 0.05). In the rumen, phyla Firmicutes and Bacteroidota were the most abundant bacteria, with Firmicutes being more abundant, and Bacteroidota being less abundant in the HC group than those found in the LC group. Christensenellaceae_R-7_group and Prevotella are the highest abundant ones at the genus level. The relative abundance of Acetitomaculum, Ruminococcus, and Candidatus_Saccharimonas were significantly higher in the HC group than that in the LC group (p < 0.05), while the relative abundance of Olsenella was significantly lower in the HC group than in the LC group (p < 0.05). Compared to the LC group, the relative abundance of Prevotella, Ruminococcus, and Candidatus_Saccharimonas was significantly higher in the HC group. The relative abundances of Prevotella, Prevotellaceae_UCG-003, Olsenella, Ruminococcus, Acetitomaculum, Candidatus_Saccharimonas, and NK4A214_group were correlated with ruminal fermentation parameters (p < 0.05). Furthermore, PICRUSt 2 estimation indicated that microbial genes associated with valine, leucine, and isoleucine biosynthesis were overexpressed in the rumen microflora of yaks in the HC group (p < 0.05). Conclusively, our results suggest that high concentrate diets affect the microflora composition and fermentation function in yak rumen. The present findings would provide new insights into the health of yaks under high concentrate feeding conditions and serve as a potent reference for the short-term fattening processes of yaks.