Effect of Finishing System on Subcutaneous Fat Melting Point and Fatty Acid Composition

Authors: DUCKETT, S - Clemson University; Neel, James; LEWIS, R - Virginia Polytechnic Institution & State University; SWECKER, W - Virginia Polytechnic Institution & State University; FONTENOT, J - Virginia Polytechnic Institution & State University; Clapham, William

Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2010
Publication Date: 7/11/2010
Citation: Duckett, S.K., Neel, J.P., Lewis, R., Swecker, W., Fontenot, J.P., Clapham, W.M. 2010. Effect of Finishing System on Subcutaneous Fat Melting Point and Fatty Acid Composition. Journal of Animal Science, 88(Suppl 2):68.

Interpretive Summary:

Technical Abstract: Angus-cross steers (n = 69) were used to determine the effect of finishing system on subcutaneous fat melting point and fatty acid composition. Three finishing systems were evaluated: 1) mixed pasture for 134 d [MP], 2) mixed pasture for 93 d and alfalfa for 41 d [AL], or 3) concentrate finishing for 134 d [CONC], in a two-year study. Subcutaneous fat samples at the 12th rib were obtained at 24 h postmortem. Melting point was determined using the OptiMelt Automated Melting Point System. Total saturated fatty acid (SFA) and omega-3 fatty acid contents were greater (P < 0.05) for AL and MP than CONC. Monounsaturated fatty acid and omega-6 polyunsaturated fatty acid contents were greater (P < 0.05) for CONC than AL and MP. The ratio of omega-6 to omega-3 fatty acids was higher for CONC (8.81) than forages (1.64), regardless of forage species grazed. Average temperature for onset point, start of melting point where liquid first appears, was higher (P <0.05) for MP and AL than CONC. Average temperature for clear point, melting point where fat is completely liquid, was higher (P < 0.05) for MP and AL than CONC. Melting point was highly, positively correlated with SFA (r = 0.73) and highly, negatively correlated with MUFA (r = -0.78) and omega-6 (r = - 0.60). Prediction equations for s.c. fat melting point included MUFA and SFA contents, and explained 83% or 93% of the variation for AL and MP, respectively. Prediction equations for s.c. fat melting point included omega-3, omega-6 and SFA, and explained 57% of the variation for CONC. Finishing system altered subcutaneous fat composition and melting point. Finishing on forages (MP and AL) increased SFA by 17% and decreased MUFA by 24%, which translated to a higher subcutaneous fat melting point (42.35 vs. 38.64 C).