Effect of the supplementation of dairy sheep diet with incremental amounts of sunflower oil on animal performance and milk fatty acid profile

The aim of this study was to investigate a suitable amount of sunflower oil (SO) inclusion in dairy sheep diet, in order to enhance the milk content of some potentially healthy fatty acids (FA; such as cis-9 trans-11 C18:2 –RA- and trans-11 C18:1 –VA-) without increasing other potentially unhealthy FA (such as trans-10 C18:1) or detrimentally affecting animal performance. Eighty dairy ewes were allocated to 4 treatments: no lipid supplementation (control), supplementation with 17 (SO1), 34 (SO2), or 51 (SO3) g of SO per kg of dry matter, for 28 days. Incremental amounts of dietary SO did not affect milk production nor the milk’s fat, protein and lactose contents. However, the FA profile was substantially modified. Treatment SO3 caused the highest enrichment in VA and RA and decreases in saturated FA, but it also enhanced the accumulation of trans-10 C18:1, which might jeopardise potentially the health-promoting properties of the ewe milk fat.