Effects of feeding supplemented with Olea europaea L. polyphenols on plasma fatty acid profile in lactating Holstein-Friesian cows

The aim of this study was to evaluate the effects of feeding feed supplemented with bioactive molecules from Olea europaea L. on the plasma fatty acid profile of Holstein-Friesian cows in mid-lactation. The experimental group was fed for 60 days with feed supplemented with natural olive extract Phenofeed® Dry (500 mg/head/day) composed mainly of hydroxytyrosol, tyrosol and verbascoside. The total polyphenol content and antioxidant power of the feed and pure extract were evaluated by Folin-Ciocalteu assay and DPPH method, and an HPLC-UV characterization of the bioactive molecules in the Phenofeed® Dry extract was performed. The plasma fatty acid profile was determined by gas chromatography. The administration of Phenofeed® Dry induced an increase in the ratio of omega-6/omega-3 polyunsaturated fatty acids (PUFA) from 3:1 to 4:1, which remains in the optimal range, helped to maintain constant levels of monounsaturated (MUFA) and saturated (SFA) fatty acids, and resulted in significant increase in polyunsaturated fatty acids as early as 15 days after administration of the functionalized feed. The results show that the feed ration of lactating cows supplemented with natural plant-derived functional molecules such as polyphenols helps maintain the optimal plasma fatty acid profile in Holstein-Frisiean dairy cows.