藏绵羊暖、冷季瘤胃微生物菌群密度与其短链脂肪酸浓度互作分析

针对藏绵羊暖、冷季营养供给严重不均衡的生产实际,本试验旨在解析藏绵羊应对冷季营养严重匮乏的适应机制。试验选择1周岁(±1月龄)健康的放牧藏绵羊母羊12只,采用气相色谱仪和荧光定量PCR仪分别测定藏绵羊暖(7月)、冷(12月)季瘤胃短链脂肪酸(SCFA)浓度和微生物菌群密度,分析藏绵羊暖、冷季瘤胃SCFA浓度与微生物菌群密度间的互作关系。结果表明:藏绵羊冷季瘤胃中乙酸与丙酸浓度及比值(A/P)显著高于暖季(P<0.05),其他SCFA浓度在暖、冷季间差异不显著(P>0.05);各种SCFA所占比例分析发现,乙酸比例在冷季显著高于暖季(P<0.05),丁酸比例在暖季显著高于冷季(P<0.05),异丁酸比例在暖、冷季间差异不显著(P>0.05)。随着季节的变化,藏绵羊瘤胃微生物中黄色瘤胃球菌(Ruminococcus flavefaciens)、白色瘤胃球菌(Ruminococcus albus)、产琥珀酸丝状杆菌(Fibrobacter succinogenes)、溶纤维丁酸弧菌(Butyrivibrio fibrisolvens)、嗜淀粉瘤胃杆菌(Ruminobacter amylophilus)与产甲烷菌(Methanogenic bacteria)的相对密度在暖季显著高于冷季(P<0.05)。相关性分析表明,乙酸浓度与黄色瘤胃球菌相对密度,丙酸浓度与白色瘤胃球菌相对密度呈极显著正相关(P<0.01),乙酸浓度与白色瘤胃球菌、嗜淀粉瘤胃杆菌、溶纤维丁酸弧菌、产甲烷菌相对密度,丙酸浓度与产琥珀酸丝状杆菌相对密度呈显著负相关(P<0.05),丁酸浓度与6种微生物菌种相对密度无显著相关性(P>0.05)。由此可见,藏绵羊瘤胃微生物菌群密度与SCFA浓度间的互作存在明显差异,这种互作机制可能在藏绵羊应对暖、冷季的适应性方面发挥着重要作用,研究结果将为藏绵羊产业发展及种质资源保护利用提供参考。

Interaction between Rumen Microbial Density and Short Chain Fatty Acid Concentration in Tibetan Sheep during Warm and Cold Seasons

The adaptation mechanism of Tibetan sheep to the severe nutrient deficiency in the cold season was analyzed in view of the production reality of the serious imbalance of nutrient supply in the warm season and the cold season.In this study,twelve one full year of life(plus or minus 1 months)health of grazing sheep ewes were selected,using gas chromatograph and fluorescence quantitative PCR,respectively detected the rumen short chain fatty acid(SCFA)concentration and microbial flora density of Tibetan sheep in warm(July)and cold(December)season,and analyzed the interaction relationship between rumen SCFA concentration and microbial flora density.The results showed that the concentration and ratio of acetic acid and propionic acid in the rumen of Tibetan sheep in the cold season were significantly higher than those in the warm season(P<0.05),while the other SCFA concentrations were not significantly different between the warm season and the cold season(P>0.05).By analyzing the proportion of various SCFA,it was found that the proportion of acetic acid was significantly higher in the cold season than in the warm season(P<0.05),the proportion of butyric acid was significantly higher in the warm season than in the cold season(P<0.05),and the proportion of isobutyric acid was not significantly different between the warm season and the cold season(P>0.05).As the season change,the relative density of Ruminococcus flavefaciens,Ruminococcus albus,Fibrobacter succinogenes,Butyrivibrio fibrisolvens,Ruminobacter amylophilus and Methanogenic bacteria were significantly higher in the warm season than the cold season(P<0.05).Correlation analysis showed that the concentration of acetic acid and the relative density of Ruminococcus flavefaciens,the concentration of propionic acid and the relative density of Ruminococcus albus had a significant positive correlation(P<0.01),the concentration of acetic acid and the relative density of Ruminococcus albus,Ruminobacter amylophilus,Butyrivibrio fibrisolvens and methanogenic bacteria had a significant negative correlation(P<0.05),butyric acid concentration and 6 kinds of microorganism strains relative density had no significant correlation(P>0.05).Therefore,the interaction between the rumen microflora density of Tibetan sheep and the concentration of SCFA is significantly different,and this interaction mechanism may play an important role in the adaptation of Tibetan sheep to warm and cold seasons.The research results will provide references for the development of Tibetan sheep industry and the protection and utilization of germplasm resources.