The aim of this study was to investigate the effects of ensiled agricultural byproducts from Qinghai-Tibet plateau on growth performance, rumen microbiota, ruminal epithelium morphology, and nutrient transport-related gene expression in Tibetan sheep. Fourteen male Tibetan sheep were randomly assigned to one of two diets: an untreated diet (without silage inoculum, CON, n = 7) or an ensiled diet (with silage inoculum, ESD, n = 7). The total experimental period lasted for 84 d, including early 14 d as adaption period and remaining 70 d for data collection. The ESD increased average daily gain (P = 0.046), dry matter intake (P < 0.001), ammonia nitrogen (P = 0.045), microbial crude protein (P = 0.034), and total volatile fatty acids concentration (P < 0.001), and decreased ruminal pH value (P = 0.014). The proportion of propionate (P = 0.006) and the copy numbers of bacteria (P = 0.01) and protozoa (P = 0.002) were higher, while the proportion of acetate (P = 0.028) was lower in the sheep fed ESD compared to CON. Pyrosequencing of the 16S ribosomal RNA gene revealed that ESD increased the relative abundance of Firmicutes, Ruminococcus, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, and Christensenellaceae_R-7_group in the rumen (P < 0.05), while decreased the relative abundance of Bacteroidota, Prevotellaceae_UCG-003, and Veillonellaceae_UCG-001 (P < 0.05). Analyses with PICRUSt2 and STAMP indicated that the propionate metabolism pathway was enriched in the sheep fed ESD (P = 0.026). The ESD increased the rumen papillae height (P = 0.012), density (P = 0.036), and surface area (P = 0.001), and improved the thickness of the total epithelia (P = 0.018), stratum corneum (P = 0.040), stratum granulosum (P = 0.042), and stratum spinosum and basale (P = 0.004). The relative mRNA expression of cyclin-dependent Kinase 2, CyclinA2, CyclinD2, zonula occludens-1, Occludin, monocarboxylate transporter isoform 1 (MCT1), MCT4, sodium/potassium pump, and sodium/hydrogen antiporter 3 were higher in the rumen epithelial of sheep fed ESD than CON (P < 0.05). Conversely, the relative mRNA expressions of Caspase 3 and B-cell lymphoma-2 were lower in the sheep fed ESD than CON (P < 0.05). In conclusion, compared with an untreated diet, feeding an ensiled diet altered the rumen microbial community, enhanced nutrient transport through rumen epithelium, and improved the growth performance of Tibetan sheep. Tibetan sheep on the Qinghai-Tibet Plateau experience significant nutrient stress while a substantial amount of agricultural byproducts in the region go discarded and wasted. In this study, agricultural byproducts were ensiled and fed to the Tibetan sheep to investigate their effects on growth performance, rumen microorganisms, and nutrient transport through rumen epithelial tissues. Fourteen male Tibetan sheep were randomly assigned to one of two diets: untreated diet (without silage inoculum, CON, n = 7) or ensiled diet (with silage inoculum, ESD, n = 7). After 70 d of feeding, the ESD-fed sheep had a higher body weight than CON. The ensiled diet changed the rumen microbial community and increased the relative abundance of cellulolytic bacteria in the rumen. In addition, the ensiled diet also promoted the development of rumen epithelia and improved the relative expression of gene related to nutrient transport. Overall, the ensiled diet optimized the use of agricultural byproducts and significantly contributed to the production of Tibetan sheep.

This study investigates the effect of altitude on the fatty acid composition of pasture grass, yak milk, and yak ghee on the Qinghai–Tibet Plateau, aiming to understand how environmental factors influence the nutritional quality of these products. Samples were collected from four different altitudes and analyzed for fatty acid profiles using gas chromatography. The analysis reveals that higher altitudes are associated with an increased prevalence of beneficial unsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2n6c). These findings highlight the significant influence of altitude on yak lipid metabolism, ultimately enhancing the nutritional value of dairy products. This adaptation not only supports the health and resilience of yaks, but also provides vital nutritional benefits to residents in high-altitude regions. The research underscores the importance of further investigations to optimize dairy production practices, ensuring improved food security and health outcomes for residents of the plateau.

IntroductionThe dietary protein level plays a crucial role in maintaining the equilibrium of rumen microbiota in yaks. To explore the association between dietary protein levels, rumen microbiota, and muscle metabolites, we examined the rumen microbiome and muscle metabolome characteristics in yaks subjected to varying dietary protein levels.MethodsIn this study, 36 yaks were randomly assigned to three groups (n = 12 per group): low dietary protein group (LP, 12% protein concentration), medium dietary protein group (MP, 14% protein concentration), and high dietary protein group (HP, 16% protein concentration).Results16S rDNA sequencing revealed that the HP group exhibited the highest Chao1 and Observed_species indices, while the LP group demonstrated the lowest. Shannon and Simpson indices were significantly elevated in the MP group relative to the LP group (P < 0.05). At the genus level, the relative abundance of Christensenellaceae_R-7_group in the HP group was notably greater than that in the LP and MP groups (P < 0.05). Conversely, the relative abundance of Rikenellaceae_RC9_gut_group displayed an increasing tendency with escalating feed protein levels. Muscle metabolism analysis revealed that the content of the metabolite Uric acid was significantly higher in the LP group compared to the MP group (P < 0.05). The content of the metabolite L-(+)-Arabinose was significantly increased in the MP group compared to the HP group (P < 0.05), while the content of D-(-)-Glutamine and L-arginine was significantly reduced in the LP group (P < 0.05). The levels of metabolites 13-HPODE, Decanoylcarnitine, Lauric acid, L-(+)-Arabinose, and Uric acid were significantly elevated in the LP group relative to the HP group (P < 0.05). Furthermore, our observations disclosed correlations between rumen microbes and muscle metabolites. The relative abundance of NK4A214_group was negatively correlated with Orlistat concentration; the relative abundance of Christensenellaceae_R-7_group was positively correlated with D-(-)-Glutamine and L-arginine concentrations.DiscussionOur findings offer a foundation for comprehending the rumen microbiome of yaks subjected to different dietary protein levels and the intimately associated metabolic pathways of the yak muscle metabolome. Elucidating the rumen microbiome and muscle metabolome of yaks may facilitate the determination of dietary protein levels.

本试验旨在研究不同精粗比对牦牛粪便菌群结构的影响.选取24头体重相近、健康的3岁公牦牛,随机分成2组,分别饲喂低精粗比饲粮(35∶65,C35组)和高精粗比饲粮(65∶35,C65组).预试期为15 d,试验期为90 d.运用16S rDNA高通量测序技术对粪便菌群结构变化进行分析.结果表明:1)2组共检测出1702个操作分类单元(OTU),其中两组共有的OTU数目为1273个,占总OTU数目的74.79％;C35组的物种数、Chao1指数与Shannon指数显著高于C65组(P<0.05).2)在门水平下,C35组牦牛粪便中髌细菌门和蓝藻菌门极显著高于C65组(P<0.01),放线菌门显著高于C65组(P<0.05);C65组牦牛粪便中拟杆菌门、螺旋体门显著高于C35组(P<0.05).3)C35组牦牛粪便中瘤胃球菌属极显著高于C65组(P<0.01),毛螺菌科_NK3A20显著高于C65组(P<0.05);C65组牦牛粪便中未培养的属极显著高于C35组(P<0.01),未培养细菌属、拟普雷沃氏菌属、密螺旋体属显著高于C35组(P<0.05).4)利用PICRUSt预测粪便微生物的代谢途径和功能,在KEGG2水平,C65组复制和修复、翻译、核苷酸代谢、其他次生代谢物的合成、细胞生长和死亡的基因家族相对丰度极显著高于C35组(P<0.01).综上,饲粮精粗比显著影响了牦牛粪便菌群的多样性与丰富度.且饲喂高精粗比饲粮(65:35)促进了牦牛粪便中非纤维降解菌的增殖,提高了拟普雷沃氏菌属的丰度值,但抑制了毛螺菌科的生长,研究结果丰富了对牦牛粪便菌群结构的认识.

本试验旨在研究饲粮不同蛋白质水平对舍饲牦牛生长性能、瘤胃发酵参数及菌群结构和功能的影响.试验选取36头体重为(200±20)kg、健康状况良好的成年公牦牛,随机分为3组,每组3个重复,每个重复4头牦牛.在饲粮代谢能(10.6 MJ/kg)一致的前提下,分别配制低蛋白质水平饲粮(12％,LP组)、中蛋白质水平饲粮(14％,MP组)、高蛋白质水平饲粮(16％,HP组).预试期15 d,正试期90 d.结果表明:1)MP组牦牛平均 日增重显著高于LP组和HP组(P＜0.05);LP组干物质采食量显著高于HP组(P＜0.05);LP组料重比显著高于MP组和HP组(P＜0.05).2)LP组微生物蛋白浓度显著低于HP组(P＜0.05);MP组丙酸浓度显著低于HP组(P＜0.05).3)3个试验组共鉴定出11 989种瘤胃液特征序列,共有1 165种瘤胃液特征序列(ASVs),占总数的9.72％,LP组、MP组和HP组的ASVs数量分别为3 437、4 184和3 903种,其独占种数分别为1 351、1 978和1 790种;LP组Shannon指数显著低于MP组和HP组(P＜0.05);LP组Simpson指数显著低于MP组(P＜0.05).4)在门水平上,MP组螺旋体门(Spiro-chaetota)相对丰度显著高于其他2组(P＜0.05);LP组广古菌门(Euryarchaeota)相对丰度显著低于其他2组(P＜0.05);在属水平上,LP组与MP组克里斯藤森菌科_R-7(Christensenellaceae_R-7)相对丰度均显著低于HP组(P＜0.05).5)利用PICRUSt2来预测瘤胃细菌的代谢途径及功能,在KEGG2水平上,氨基酸代谢、能量代谢、辅助因子和维生素的代谢在HP组显著富集(P＜0.05);碳水化合物代谢、脂质代谢在LP组显著富集(P＜0.05);LP组其他氨基酸代谢显著低于HP组(P＜0.05).综上所述,饲喂相同代谢能不同蛋白质水平饲粮对舍饲牦牛生长性能、瘤胃发酵类型、瘤胃细菌丰富度、瘤胃菌群结构和瘤胃细菌代谢功能途径均会产生影响.饲喂14％蛋白质水平饲粮的舍饲牦牛具有较高的平均日增重、较低的料重比与较高的养殖效益,瘤胃微生物蛋白浓度较高,瘤胃菌群丰富度和多样性较高,且具有相对较高的蛋白质消化代谢及能量转化利用能力.综合考虑,当饲粮代谢能为10.6 MJ/kg时,推荐舍饲牦牛饲粮蛋白质水平为 14％.

目的 探究粪菌移植对低海拔动物的高原适应性的影响.方法 将30只雄性SD大鼠随机分为3组,每组10只,即模拟高原环境组(H组)、模拟高原环境+抗生素预处理组(HA组)及模拟高原环境+抗生素预处理+高原鼢鼠粪菌组(HAM组).粪菌移植结束,持续饲养3周后,将所有组大鼠转移至模拟海拔6 000 m环境低压氧舱饲养30 d.测定粪菌移植对SD大鼠体质量、血常规指标及肠道菌群的影响.结果 HAM组、HA组和H组3组大鼠间平均日采食量比较差异无统计学意义(F=2.928,P＞0.05),H组大鼠平均日增重显著低于HA组、HAM组(F=3.951,P＜0.05);HA组大鼠中性粒细胞数量较H组、HAM组分别上升7.85％和51.27％,HA组大鼠单核细胞数、单核细胞百分比显著高于H组、HAM组(F=5.131、4.325,均P＜0.05);HAM组、HA组和H组大鼠肠道菌群的优势菌门以拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)为主.HAM组大鼠肠道菌群的毛螺菌科(Lachnospiraceae)的相对丰度显著高于HA组、H 组(F=8.545,P＜0.01),毛螺菌科 NK4A136 属(Lachnospiraceae_NK4A136_group)的相对丰度显著高于HA组、H组(F=3.926,P＜0.05).LEfSe分析显示,HAM组大鼠肠道菌群中对群落结构影响较大的物种有乳螺目(Lachnospirales)、毛螺菌科.结论 通过粪菌移植能够提高进入高原环境的低海拔动物的高原适应性.

The gut microbiota plays a crucial role in maintaining host nutrition, metabolism, and immune homeostasis, particularly in extreme environmental conditions. However, the regulatory mechanisms of the gut microbiota in animal organisms hypobaric hypoxia exposure require further study. We conducted a research by comparing SD rats treated with an antibiotic (ABX) cocktail and untreated SD rats that were housed in a low-pressure oxygen chamber (simulating low pressure and hypoxic environment at 6000 m altitude) for 30 days. After the experiment, blood, feces, and lung tissues from SD rats were collected for analysis of blood, 16S rRNA amplicon sequencing, and non-targeted metabolomics. The results demonstrated that the antibiotic cocktail-treated SD rats exhibited elevated counts of neutrophil (Neu) and monocyte (Mon) cells, an enrichment of sulfate-reducing bacteria (SBC), reduced levels of glutathione, and accumulated phospholipid compounds. Notably, the accumulation of phospholipid compounds, particularly lysophosphatidic acid (LPA), lipopolysaccharide (LPS), and lysophosphatidylcholine (LPC), along with the aforementioned changes, contributed to heightened oxidative stress and inflammation in the organism. In addition, we explored the resistance mechanisms of SD rats in lowoxygen and low-pressure environments and found that increasing the quantity of the Prevotellaceae and related beneficial bacteria (especially Lactobacillus) could reduce oxidative stress and inflammation. These findings offer valuable insights into enhancing the adaptability of low-altitude animals under hypobaric hypoxia exposure.

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.

在国内饲料端禁抗的背景下,寻找具有提高动物生产性能和免疫力、降低料重比的优质饲料成为研究热点.与常规饲料相比,发酵饲料能够提高动物的生产性能和免疫力,降低料重比,调节瘤胃菌群平衡.文章从发酵饲料的种类、作用机制、营养价值及其在反刍动物养殖中的应用等方面进行综述,以期为青藏地区发酵饲料的开发及其在牦牛养殖中的应用推广提供参考.

Rumen fluid transplantation（RT）is a technique for transferring rumen fluid from healthy donor animals to recipient animals. Currently,the reports on RT are relatively limited,but more and more research results show that rumen fluid transplantation can affect the dry matter intake and milk production of ruminants,and has the potential to reconstruct the rumen microbiota structure. In this paper,the methods of rumen fluid transplantation and its application in practice were reviewed,and the influences of RT on growth performance,rumen fermentation and rumen microflora of ruminants and its role in the treatment of certain diseases were analyzed to provide reference for the research and application of RT in ruminants.[Chinese Journal of Animal Nutrition,2023,35（4）:2105-2110]

为研究欧拉型母羊妊娠后期饲料中适宜的钙磷(Ca、P)水平,在青藏高原寒冷牧区粗饲料的条件下,试验选择60只2～3岁的欧拉型妊娠后期母羊,体重为(55.42±2.37)kg,随机分成4个组(每组15只).根据Ca、P含量的不同,分别为A组(Ca 0.08％、P 0.32％)、B组(Ca 0.18％、P 0.38％)、C组(Ca 0.59％、P 0.60％)、D组(Ca 1.01％、P 0.83％),每个处理组饲喂一种精料.试验预试期10 d,正试期60 d.试验结果显示:随着饲粮中Ca、P水平的逐渐增加,母羊平均日增重(ADG)、排粪量、磷表观消化率、血清Ca等都没有发生明显的变化.同一处理组在各个时间段:血清甲状腺素,B、C两组在第30 d时显著高于第1 d和第60 d(P<0.05);生长激素,A、B两组第1 d显著高于第30 d、第60 d(P<0.05);不同的处理组在同一时间段:血清P,在第30 d和第60 d,C、D两组显著高于A处理组(P<0.05);血清甲状腺素,在第30 d时,A处理组显著低于B、C两组(P<0.05);生长激素,在第30 d和第60 d,C组显著高于A、B、D 3组(P<0.05).综上所述,对于体重在55 kg左右的欧拉型妊娠后期母羊而言,日粮中适宜Ca、P水平分别为7.5 g/d、4.23 g/d.

试验旨在比较分析不同季节条件下对放牧牦牛生长性能及血清生化指标的影响.选取8头体况良好的健康牦牛为研究对象,分别于暖季和冷季在同一草场放牧.预试期10 d,正式试验期60 d.结果显示:暖季组牦牛的总增重及平均日增重极显著高于冷季组(P＜0.01).暖季组牦牛的血清白蛋白、谷丙转氨酶活性显著高于冷季组(P＜0.05).研究表明,暖季牦牛的生长状况明显比冷季好,对蛋白质的消化吸收利用情况更好,增重效果也更好.

本试验旨在研究不同饲养方式对6月龄断奶牦牛犊牛生长性能、瘤胃发酵及菌群结构的影响.试验选择30头出生日期接近、体重在(51.72±3.15)kg的健康牦牛犊牛,随机分为舍饲组和放牧组,每组15头.舍饲组犊牛饲粮精粗比为65:35,放牧组犊牛08:30放牧、17:30归牧,不进行补饲.预试期10 d,正试期210 d.结果表明:1)舍饲组牦牛犊牛体重、体高、体斜长、胸围、管围极显著高于放牧组(P＜0.01).2)舍饲组牦牛犊牛瘤胃液氨态氮、总挥发性脂肪酸、丙酸、丁酸、异丁酸、戊酸和异戊酸浓度极显著高于放牧组(P＜0.01),微生物蛋白和乙酸浓度显著高于放牧组(P＜0.05),而pH、乙酸/丙酸值极显著低于放牧组(P＜0.01).3)2组中检测到操作分类单元(OTU)总数为5 154个,舍饲组和放牧组特有OTU数分别为1 089和898个,分别占OTU总数的21.13％和17.42％;放牧组ACE指数、Chao1指数、Shannon指数显著或极显著高于舍饲组(P＜0.05或P＜0.01).4)在门水平上,2组牦牛犊牛瘤胃优势菌门均为厚壁菌门(Fir-micutes)、拟杆菌门(B acteroidetes)和变形菌门(Proteobacteria),在舍饲组中的相 对丰度分别为46.02％、23.94％和8.86％,在放牧组中的相对丰度分别为53.96％、25.62％和7.50％;在属水平上,舍饲组和放牧组牦牛犊牛瘤胃中存在相同的微生物,但所占比例不同,理研菌科RC9肠道群(Rikenellaceae_RC9_gut_group)是2个组中共有的优势菌属,相对丰度分别为11.77％、6.92％.综上所述,与放牧相比,舍饲提高了牦牛犊牛的生长性能,促进了瘤胃发酵,但在一定程度上降低了瘤胃菌群的多样性与丰富度.

To improve the rumen fermentation function and growth performance of yaks (Bos grunniens), better understanding of the effect of different dietary forage to concentrate ratios on rumen microbiota and metabolites is needed. In the present study, three diets with different dietary forage to concentrate ratios (50:50, 65:35, and 80:20) were fed to 36 housed male yaks. The changes in the distribution of rumen microorganisms and metabolites and the interactions between them were studied by 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS). The diversity and richness of microorganisms in the rumen varied according to diet. The most abundant phyla were Firmicutes and Bacteroidetes. Firmicutes was the most abundant in the C50 group, and the relative abundance of Bacteroidetes was significantly lower in the C65 group than in the C80 group (p < 0.05). The Christensenellaceae_R-7_group, Rikenellaceae_RC9_gut_group, and Methanobrevibacter had the highest relative abundances at the genus level. Among them, Christensenellace_R-7_group had the highest relative abundance in the C50 group. The Rikenellaceae_RC9_gut_group was significantly abundant in the C80 group compared with the C50 group. The Methanobrevibacter content was higher in the C65 group than in the other two groups. Both the concentration and metabolic pathways of rumen metabolites were influenced by the dietary concentrate ratio; lipids, lipid-like molecules, organic acid metabolites, and organic oxide-related metabolites differed between the groups. Significant changes were found for six metabolic pathways, including arginine and proline metabolism; glycine, serine, and threonine metabolism; glyoxylate and dicarboxylate metabolism; arginine biosynthesis; glycerophospholipid metabolism; glycerolipid metabolism; and nitrogen metabolism.

为了研究精料补饲水平对暖季放牧牦牛瘤胃发酵和菌群结构的影响,试验选取体重相近、体况良好的公牦牛48头,随机分为4组,每组12头,以放牧为对照组,3个补饲组分别补饲0.5(Ⅰ)、1.5(Ⅱ)和2.5 kg·d-1(Ⅲ)精料.预试期10 d,正式期60 d.结果表明:1)随着精料补饲水平的提高,瘤胃液pH值,乙酸浓度和乙酸/丙酸值呈线性和二次降低(P<0.05);瘤胃总挥发性脂肪酸、丙酸、丁酸、异丁酸、戊酸和异戊酸浓度呈线性和二次提高(P<0.05);其中补饲Ⅱ和Ⅲ组的微生物蛋白浓度显著高于其他两组(P<0.05).2)4组共产生3138个OTU,其中共有OTU为1337个,占总OTU数目的42.61％,对照组与补饲Ⅲ组独有OTU分别为183和106个;瘤胃液细菌的物种数、Chao1指数和香农(Shannon)指数随精料补饲的提高呈线性和二次降低(P<0.05).3)在门水平上,瘤胃拟杆菌门(Bacteroidetes)相对丰度呈线性和二次提高(P<0.05);而厚壁菌门(Firmicutes)相对丰度随精料补饲水平提高呈线性和二次降低(P<0.05);放线菌门(Actinobacteria)相对丰度随精料补饲水平的提高呈线性提高(P<0.05).在属水平上,随精料补饲水平的提高,瘤胃普雷沃菌属_1(Prevotella_1)、克里斯滕森菌科_R-7(Christensenellaceae_R-7)及普雷沃氏菌科_UCG-001(Prevotellaceae_UCG-001)相对丰度呈线性和二次提高(P<0.05);而解琥珀酸菌属(Succiniclasticum)和瘤胃球菌科_UCG-005(Ruminococcaceae_UCG-005)相对丰度随着精料补饲水平的提高呈线性和二次降低(P<0.05).综上所述,适宜提高精料补饲水平能够促进暖季放牧牦牛瘤胃发酵,提高瘤胃部分淀粉相关降解菌的丰度.

本研究旨在比较不同饲养方式对牦牛瘤胃发酵参数及微生物菌群的影响.试验选取3周岁、体重[(176.3±14.7)kg]相近、体况良好的公牦牛20头,随机分为舍饲组(全混合日粮)和放牧组(放牧),每组10头牛.预试期10 d,正试期90 d.结果表明:1)舍饲组瘤胃总挥发性脂肪酸(TVFA)、乙酸、丙酸、丁酸浓度显著高于放牧组(P<0.05),而瘤胃pH显著低于放牧组(P<0.05).2)舍饲组瘤胃微生物菌群Chao1指数显著高于放牧组(P<0.05).3)在门水平上,舍饲组瘤胃Saccharibacteria、迷踪菌门(Elusimicrobia)、拟杆菌门(Bacteroidetes)、螺旋体门(Spiro?chaetae)、软壁菌门(Tenericutes)相对丰度显著高于放牧组(P<0.05),而放牧组瘤胃浮霉菌门(Planctomycetes)、互养菌门(Synergistetes)和厚壁菌门(Firmicutes)相对丰度显著高于舍饲组(P<0.05).在属水平,舍饲组瘤胃Candidatus_Saccharimonas、醋酸杆菌属(Acetobacter)、螺旋体属_2(Spirochaeta_2)、凸腹真杆菌属(Eubacterium_ventriosum_group)和乳酸杆菌属(Lactoba?cillus)相对丰度显著高于放牧组(P<0.05),而放牧组瘤胃罗斯氏菌属(Rosebuna)、狭义梭菌属(Clostridium_sensu_stricto_1)、Family?ⅩⅢ?AD3011、丁酸弧菌属_2(Butybrivibrio_2)和奎因氏菌属(Quinella)相对丰度显著高于舍饲组(P<0.05).4)利用PICRUSt预测瘤胃微生物的代谢途径和功能,在KEGG2水平,舍饲组能量代谢(energy metabolism)、核苷酸代谢(nucleotide metab?olism)、转录(transcription)、运输和分解代谢(transport and catabolism)基因家族相对风丰度显著高于放牧组(P<0.05).综上所述,与放牧相比,全混合日粮舍饲育肥提高了牦牛瘤胃内非纤维物质的降解菌以及半纤维降解菌属的相对丰度,同时增加了VFA浓度,并且牦牛的能量代谢通路上调,促进了牦牛的高效代谢,有助于加快牦牛的生长发育.

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.

本试验旨在研究不同能量和蛋白质水平饲粮对牦牛肉品质的影响.试验选用45头健康、年龄和体重相近的成年公牦牛,随机分成9个组,分别为低能低蛋白质组(Ⅰ组)、低能中蛋白质组(Ⅱ组)、低能高蛋白质组(Ⅲ组)、中能低蛋白质组(Ⅳ组)、中能中蛋白质组(Ⅴ组,对照组)、中能高蛋白质组(Ⅵ组)、高能低蛋白质组(Ⅶ组)、高能中蛋白质组(Ⅷ组)和高能高蛋白质组(Ⅸ组),每组5头牛.采用2因素3水平试验设计,3个能量(代谢能)水平分别为9.5(低能)、10.6(中能)和11.7 MJ/kg(高能),3个粗蛋白质水平分别为12％(低蛋白质)、14％(中蛋白质)和16％(高蛋白质),按3×3设计9种不同能量和蛋白质水平的全混合日粮.试验预试期10 d,正试期180 d.结果表明:1)与Ⅴ组(对照组)相比,Ⅲ组和Ⅳ组牦牛背最长肌45 min时的pH显著降低(P＜0.05),背最长肌亮度(L*)、红度(a*)和黄度(b*)值显著提高(P＜0.05),背最长肌剪切力显著降低(P＜0.05).2)与Ⅴ组相比,Ⅶ组、Ⅷ组和Ⅸ组牦牛背最长肌硬度显著提高(P＜0.05),Ⅷ组和Ⅸ组背最长肌胶着性显著提高(P＜0.05),Ⅲ组背最长肌咀嚼性显著降低(P＜0.05).综合考虑,中能低蛋白质组牦牛背最长肌在pH、肉色、剪切力和质构数据上都比较优秀,因此舍饲育肥牦牛全混合日粮的代谢能水平为10.6 MJ/kg、粗蛋白质水平为12％时肉品质较好.

为了探讨饲粮精粗比对牦牛瘤胃菌群结构的影响.试验选取36头体重相近、健康的雄性牦牛,随机分为3组,每组12头.各试验组分别饲喂精粗比为50∶50(A组)、65∶35(B组)和80∶20(C组)的饲粮,预试期为15d,正试期为90 d.在正试期第90天,晨饲前经口腔采集瘤胃液,利用16S rDNA高通量测序技术分析瘤胃液的菌群结构.结果表明:1)3组共产生3 354个操作分类单元(OTU),其中共有OTU为1 851个,占总OTU数目的55.19％;瘤胃液细菌的物种数、Chaol指数、Shannon指数及谱系多样性随饲粮精粗比的提高呈显著线性降低(P＜0.05).2)在门水平上,厚壁菌门(Firmicutes)和放线菌门(Actinobacteria)的相对丰度与饲粮精粗比呈显著线性正相关关系(P＜0.05),而拟杆菌门(Bacteroidetes)的相对丰度呈显著负相关关系(P＜0.05);试验B组的疣微菌门(Verrucomicrobia)的相对丰度显著高于其他两组(P＜0.05).3)在属水平上,随着饲粮精粗比的提高,普雷沃菌属_1(Prevotella_1)、瘤胃球菌科NK4A214菌属(Ruminococcaceae_NK4A214_group)和聚乙酸菌属(Acetitomaculum)的相对丰度呈显著线性提高(P＜0.05),而瘤胃球菌属_2(Ruminococcus_2)和螺菌科 NK3A20 菌属(Lachnospiraceae_NK3A20_group)的相对丰度呈显著线性降低(P＜0.05).综上所述,饲粮精粗比显著影响了牦牛瘤胃细菌的总数与多样性,高精粗比饲粮条件下,瘤胃中部分纤维降解菌的生长受到抑制.

This study aimed to evaluate the effects of concentrate supplementation on the growth performance, serum biochemical parameters, rumen fermentation, and bacterial community composition of grazing yaks during the warm season. Eight male yaks (body weight, 123.96 ± 7.43 kg; 3-years) were randomly allocated to two treatments groups: grazing (n = 4, GY) and concentrate supplement group (n = 4, GYS). Concentrate supplementation increased the average daily gain (ADG) (p < 0.05). Glucose (GLU), total protein (TP), and aspartate aminotransferase (AST) serum concentrations were significantly higher in the GYS group than in the GY group (p < 0.05). Ammonia-N, MCP: microbial protein, and total volatile fatty acid concentrations were significantly higher in the GYS group than in the GY group (p < 0.01), whereas the pH and acetate: propionate values were significantly decreased (p < 0.01). The relative abundance of Firmicutes in the rumen fluid was significantly higher in the GYS group than in the GY group (p < 0.01). At the genus level, the relative abundances of Succiniclasticum, Prevotellaceae_UCG_003, Prevotellaceae_UCG_005, and Ruminococcus_1 were significantly greater in the GY group than in the GYS group (p < 0.01). In conclusion, concentrate supplementation improved yaks’ growth potential during the warm season, improved ruminal fermentation, and altered core bacteria abundance.