1886
Dietary fatty acid profile affects plasma metabolic profile of peripartum Holstein cows
Concentration of plasma NEFA usually increases around calving due to mobilization of adipose tissue as a result of the inability of high-producing cows to consume enough energy to meet requirements for milk production and maintenance. Elevated NEFA concentration in the periparturient period is the major factor influencing postpartum accumulation of lipid in hepatic tissue. Whereas postpartum fat supplementation is a common practice in the dairy industry, prepartum fat supplementation is less common. The objective of this study was to examine the effect of feeding diets containing fat supplements enriched in either saturated FA or PUFA on metabolic responses of periparturient Holstein cows. 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 Palm 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. All rations contained identical forage and concentrate components. Metabolite analyses were performed on blood samples collected weekly pre and post-partum and daily from -10 to 10 days relative to expected calving from tail vein. Data were analyzed using PROC MIXED of SAS 9.1 according with repeated measures in time function. Prepartum plasma contents of glucose, triacyl glycerol, cholesterol, total protein, urea, NEFA, BHBA and glycerol were not affected by type of lipid supplement, but Insulin, LDL, HDL, albumin and TNF-α concentration significantly increased in PO supplemented group than those supplemented with Persia Fat® . In postpartum period, plasma levels of triacyl glycerol, total protein and urea were not affected by dietary fatty acid profile. However, Feeding Persia Fat®, greatly reduced plasma concentration of NEFA, BHBA and glycerol along with lowering effects for TNF-α, suggesting that feeding protected PUFA sources can manage mobilization of body reserves. Statistically significant lower glucose and higher Insulin concentration in PO fed cows, in line with higher TNF-α levels can be a hint to lower insulin sensitivity compared with Persia Fat® fed animals. Different profiles of protected PUFA sources didn’t have any significant difference.
Keywords: PUFA, Palm oil, Insulin resistance, NEFA