2017 Volume 20 Issue 1 Pages 30-38
Anion-exchange（AEX）high-performance liquid chromatography（HPLC）methods are recently developed and can measure serum lipoproteins such as high-density lipoproteins（HDL）, low-density lipoproteins（LDL）, intermediate-density lipoproteins, and very-low-density lipoproteins in humans. However, AEX-HPLC analysis has not been applied in dairy cows. The objective of this study was to investigate the reproducibility and precision of AEX-HPLC methods using serum samples from healthy dairy cows and the correlation between AEX-HPLC and other analytical methods（ultracentrifugation methods and gel permeation HPLC［GP-HPLC］）in six healthy dairy cows. Moreover, we evaluated the lipoprotein fraction in 24 dairy cows with different lactating and dry periods. Analytical reproducibility（intra- and inter-assay and diluted linearity assay）of AEX-HPLC methods in samples of dairy cows produced acceptable results. Furthermore, positive correlation coefficients between the values of total cholesterol, HDL cholesterol concentration（HDL-C）, and LDL cholesterol concentration（LDL-C）were determined between AEX-HPLC and ultracentrifugation methods and between AEX-HPLC and GP-HPLC. During different lactating and dry periods, HDL-C and LDL-C increased from the early to mid-lactation stage and decreased during the dry lactation stage in healthy dairy cows. These results suggest that AEX-HPLC would be a useful method for evaluating the lipoprotein fraction in dairy cows.
