Unrefined sunflower oil supplementation selectively influenced the milk fatty acid profile and oxidative status in Simmental cows

Ten healthy, multiparous Simmental cows in mid-lactation (78 ± 40 DIM) were assigned for cross-over feeding trial with one of the diet applied: the WSO diet that contained 26% corn silage, 33% perennial ryegrass haylage, and 41% concentrate in DM, and the SO diet where the concentrate mixture of the basal diet was supplemented with 0.2 % of non-protected sunflower oil in DM per cow and day. Three of 30 fatty acid measured were significantly changed under the influence of the SO treatment.The GPx activity significantly increased, SOD and the TBARS concentration decreased in the SO treatment.The presented results indicate significant increase of CLA and linoleic acid, and lowering effect on the palmitic acid in milk of Simmental cows supplemented by the unrefined sunflower oil in the daily ratio. Significant decrease in blood SOD activity and increase in GPx activity in cows at SO treatment might indicate provision of essential trace elements by unrefined sunflower oil and proper function of the endogenous antioxidant system during the SO supplemental feeding. The long-term influence of fat supplements on the oxidant stress balance in cows should be further studied.