Lipid Metabolism in Bovine Subcutaneous Adipose Tissue of Steers Fed Supplementary Palm Oil or Soybean Oil

Abstract

We hypothesized that supplementing finishing diets with palm oil would elevate Stearoyl-CoA desaturase (SCD) activity in muscle and subcutaneous (s.c.) adipose tissue, promoting adipocyte differentiation and increase monounsaturated fatty acids (MUFA) in beef, particularly oleic acid. Soybean oil supplementation was used as a negative control. Eighteen Angus steers were assigned randomly to three groups of 6 steers and fed a basal diet without additional fat, with 3% palm oil (rich in palmitic acid), or with 3% soybean oil (rich in polyunsaturated fatty acids), top dressed daily. There were no significant differences across treatment in quality grade, REA, 12th rib fat thickness, or yield grade. Palm oil tended to increase marbling score (P = 0.33). Palm oil supplementation decreased the concentration of myristic acid (P = 0.04), and tended to decrease the concentration of t10, c12 CLA (P = 0.07) and 18:3n-3 (P = 0.06) in s.c. adipose tissue while soybean supplementation increased c9, t11 CLA (P = 0.02) and 18:3n-3 (P = 0.03) in muscle. Palm oil supplementation increased both glucose and acetate incorporation into total lipids of s.c. adipose tissue (both P = 0.03). Volume of s.c. adipocytes was greater in cattle supplemented with palm oil than in soybean- supplemented cattle (P = 0.004). Enzyme activity of G-6-PDH tended to be greater in steers consuming palm oil supplement (P = 0.10).

We conclude that there was a partial interaction between palm oil supplementation and adipocyte differentiation. Palm oil supplementation increased s.c. adipocyte content without deteriorating meat quality traits and tended to increase marbling.