1717
Effects of feeding protected unsaturated fatty acids (Persia Fat®)on milk fatty acid profile of Iranian Holstein dairy cows
In recent years, consumer concerns about contribution of milk and dairy products to total intake of saturated fatty acids has driven extensive research about effectiveness of protected fatty acid sources in modification of milk fatty acids. The aim of this study was to evaluate the milk fatty acid profile in early lactating dairy cows supplemented with protected unsaturated fatty acids sources and prilled source of palm fatty acids. Twenty four multiparous Iranian Holstein cows were assigned to diets with different fatty acid profiles and supplemented through 30 days prior to expected calving date to 50 days in milk. Dietary treatments consisted of (1) Prilled Pam fatty acids (PO) [Energizer RP10 ®, 2 & 2.25 % DM in pre- and postpartum, respectively]; (2) Ca-salts of sunflower oil (SO) [Persia Fat®- SO]; (3) Ca-salts of fish oil (FO) [Persia Fat®- FO] and (4) equal amounts of Persia Fat®- FO & Persia Fat®- SO. Calcium salts were supplemented as 2.2 and 2.5% of dietary DM in pre- and postpartum period, respectively Milk yield and the dry matter intake were measured daily throughout the experimental period. The milk samples used for evaluating fatty acids profile were obtained weekly (2 consecutive days, each sample coming from the 3 daily milking, and were quantified by gas chromatography (Varian CP-3800, FID detector, 100 m CP-Sil88 column, GLC 463). Data were analyzed using PROC MIXED of SAS 9.1 with repeated measures in time function. Cows fed PO produced milk with higher saturated (69.90 vs. 58.14, 56.45 and 56.74, for treatments 1 to 4, respectively) and lower monounsaturated (23.37 vs. 32.22, 32.54 and 32.36, for treatments 1 to 4, respectively) polyunsaturated (2.80 vs. 7.13, 7.58 and 6.98, for treatments 1 to 4, respectively) fatty acid concentrations than cows fed diets with unsaturated fatty acid sources. All of the differences between PO and Persia Fat® sources were statistically significant, but not between unsaturated fatty acid sources. Feeding Persia Fat® increased the milk concentration of C18:0, whereas that of C16:0 was increased by PO supplementation (39.13 vs. 25.92, 23.60 and 23.72, for treatments 1 to 4, respectively). Supplementation with PO significantly increased C16 and < C16 fatty acids, whereas decreased > C16 fatty acids in milk fat. Highest (statistically significant) n-3 and n-6 fatty acids contents were belong to Persia Fat®- FO and Persia Fat®- SO, respectively.
Keywords: PUFA, Palmitic acid, Omega-3,Omega-6