Effects of Different Ratios of Short-Medium Chain Fatty Acids to Long Chain Fatty Acids on Rumen Fermentation and Metabolism of Blood Lipids in Lactating Dairy Cows

摘要

The objectives of this study were to investigate the effects of different ratios of Short-Medium Chain Fatty Acids (SMCFA) to Long Chain Fatty Acids (LCFA) on rumen fermentation and metabolism of blood lipids in lactating dairy cows. Thirty six Holstein cows (183±46 DIM) were allotted to three treatments according to randomized block design with 12 cows in each treatment. Cows in treatments were supplemented with 80 g day-1 SMCFA mixture and 320 g day-1 LCFA mixture, 400 g day-1 of butterfat, 240 g day-1 SMCFA mixture and 160 g day-1 LCFA mixture. Rumen liquid and blood samples were collected from all the cows. The results showed that supplementing different ratios of SMCFA to LCFA did not affect rumen fermentation. As the ratios of SMCFA to LCFA increased, concentrations of trans-11 18:1 linearly increased and the cis-9, cis-12 18:2 quadratically increased and peaked at 40SM60L. The contents of LCFA (>16:0) and PUFA were quadratically increased but that of SFA decreased quadratically. Simultaneously, concentrations of triglycerides in the serum quadratically increased whereas that of insulin decreased quadratically. This study demonstrated that dietary supplementation of different ratios of SMCFA to LCFA did not influence rumen fermentation but altered the plasma fatty acid composition in dairy cows.