Zhang Guanshi, Dervishi Elda, Ametaj Burim N
Department of Agricultural Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2M9, Canada.
Department of Agricultural Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Res Vet Sci. 2018 Apr;117:167-177. doi: 10.1016/j.rvsc.2017.12.008. Epub 2017 Dec 19.
The objective of this study was to search for potential alterations in innate immunity reactants and carbohydrate and lipid metabolism in the blood of transition dairy cows before, during, and after clinical occurrence of milk fever (MF) and identify potential predictive biomarkers of disease. One hundred pregnant multiparous Holstein dairy cows were involved in the study starting from -8wks before the expected day of parturition until +8wks postpartum as part of a large retrospective longitudinal study. Health status, DMI, milk yield, and milk composition were monitored during the whole experimental period. Six healthy cows (CON) and 6 cows that showed clinical signs of MF were selected for blood analyses. Serum concentrations of lactate, non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), haptoglobin (Hp), and serum amyloid A (SAA) were determined. Results indicated that concentrations of serum lactate, IL-6, TNF, SAA, and Hp were greater in cows with MF than those in the CON group at different time points. Moreover, serum lactate, TNF, SAA, and Hp were greater in cows with MF starting at -8 and -4wks prior to parturition. Both principal component analysis (PCA) and partial least squares - discriminant analysis (PLS-DA) showed separated clusters between MF and CON cows at -8, -4, and disease diagnosis weeks. Overall DMI and milk production were lower in MF-affected cows. Additionally milk fat and fat:protein ratio were greater in MF. In conclusion, cows affected by MF showed alterations in some of the innate immunity reactants and metabolites related to carbohydrate metabolism several weeks prior to appearance of clinical signs of MF. Variable importance in projection plots demonstrated that TNF and SAA in the serum were the strongest discriminators between MF cows and CON ones, which might be useful as predictive biomarkers of the disease.
本研究的目的是探寻围产奶牛在临床发生产乳热（MF）之前、期间及之后血液中天然免疫反应物以及碳水化合物和脂质代谢的潜在变化，并确定该疾病的潜在预测生物标志物。作为一项大型回顾性纵向研究的一部分，100头怀孕的经产荷斯坦奶牛参与了本研究，从预计分娩日期前8周开始直至产后8周。在整个实验期间监测健康状况、干物质采食量（DMI）、产奶量和牛奶成分。选择6头健康奶牛（CON）和6头出现MF临床症状的奶牛进行血液分析。测定血清乳酸、非酯化脂肪酸（NEFA）、β-羟基丁酸（BHBA）、白细胞介素-1（IL-1）、白细胞介素-6（IL-6）、肿瘤坏死因子（TNF）、触珠蛋白（Hp）和血清淀粉样蛋白A（SAA）的浓度。结果表明，在不同时间点，患MF的奶牛血清乳酸、IL-6、TNF、SAA和Hp的浓度高于CON组奶牛。此外，在分娩前-8周和-4周开始，患MF的奶牛血清乳酸、TNF、SAA和Hp更高。主成分分析（PCA）和偏最小二乘判别分析（PLS-DA）均显示在-8周、-4周和疾病诊断周时，MF奶牛和CON奶牛之间存在分离的聚类。受MF影响的奶牛总体DMI和产奶量较低。此外，MF奶牛的乳脂和脂肪与蛋白质的比例更高。总之，受MF影响的奶牛在出现MF临床症状前几周，其一些天然免疫反应物和与碳水化合物代谢相关的代谢产物发生了变化。投影图中的变量重要性表明，血清中的TNF和SAA是MF奶牛和CON奶牛之间最强的判别指标，可能作为该疾病的预测生物标志物。
