Zhang Hua, Tong Jinjin, Zhang Yonghong, Xiong Benhai, Jiang Linshu
Beijing Key Laboratory for Dairy Cow Nutrition, Beijing University of Agriculture, Beijing, 102206, China.
Beijing Bei Nong Enterprise Management Co., Ltd., Beijing 102206, China.
Asian-Australas J Anim Sci. 2020 Jan;33(1):79-90. doi: 10.5713/ajas.19.0214. Epub 2019 Aug 23.
In the present study, an liquid chromatography/mass spectrometry (LC/MS) metabolomics approach was performed to investigate potential biomarkers of milk production in high- and low-milk-yield dairy cows and to establish correlations among rumen fluid metabolites.
Sixteen lactating dairy cows with similar parity and days in milk were divided into high-yield (HY) and low-yield (LY) groups based on milk yield. On day 21, rumen fluid metabolites were quantified applying LC/MS.
The principal component analysis and orthogonal correction partial least squares discriminant analysis showed significantly separated clusters of the ruminal metabolite profiles of HY and LY groups. Compared with HY group, a total of 24 ruminal metabolites were significantly greater in LY group, such as 3-hydroxyanthranilic acid, carboxylic acids, carboxylic acid derivatives (L-isoleucine, L-valine, L-tyrosine, etc.), diazines (uracil, thymine, cytosine), and palmitic acid, while the concentrations of 30 metabolites were dramatically decreased in LY group compared to HY group, included gentisic acid, caprylic acid, and myristic acid. The metabolite enrichment analysis indicated that protein digestion and absorption, ABC transporters and unsaturated fatty acid biosynthesis were significantly different between the two groups. Correlation analysis between the ruminal microbiome and metabolites revealed that certain typical metabolites were exceedingly associated with definite ruminal bacteria; Firmicutes, Actinobacteria, and Synergistetes phyla were highly correlated with most metabolites.
These findings revealed that the ruminal metabolite profiles were significantly different between HY and LY groups, and these results may provide novel insights to evaluate biomarkers for a better feed digestion and may reveal the potential mechanism underlying the difference in milk yield in dairy cows.
在本研究中，采用液相色谱/质谱（LC/MS）代谢组学方法来研究高产和低产奶牛产奶量的潜在生物标志物，并建立瘤胃液代谢物之间的相关性。
将16头胎次和泌乳天数相似的泌乳奶牛根据产奶量分为高产（HY）组和低产（LY）组。在第21天，应用LC/MS对瘤胃液代谢物进行定量分析。
主成分分析和正交校正偏最小二乘判别分析显示，HY组和LY组瘤胃代谢物谱有明显分离的聚类。与HY组相比，LY组共有24种瘤胃代谢物显著增加，如3-羟基邻氨基苯甲酸、羧酸、羧酸衍生物（L-异亮氨酸、L-缬氨酸、L-酪氨酸等）、二嗪类（尿嘧啶、胸腺嘧啶、胞嘧啶）和棕榈酸，而LY组中30种代谢物的浓度与HY组相比显著降低，包括龙胆酸、辛酸和肉豆蔻酸。代谢物富集分析表明，两组之间蛋白质消化吸收、ABC转运蛋白和不饱和脂肪酸生物合成存在显著差异。瘤胃微生物群与代谢物的相关性分析表明，某些典型代谢物与特定的瘤胃细菌密切相关；厚壁菌门、放线菌门和协同菌门与大多数代谢物高度相关。
这些发现表明，HY组和LY组的瘤胃代谢物谱存在显著差异，这些结果可能为评估生物标志物以实现更好的饲料消化提供新的见解，并可能揭示奶牛产奶量差异的潜在机制。
