Journal of Animal Science, Vol 76, Issue 3 743-749, Copyright © 1998 by American Society of Animal Science

JOURNAL ARTICLE

Physiological adaptations in adipose tissue of Brahman vs Angus heifers

J. E. Sprinkle, H. S. Hansard, B. G. Warrington, J. W. Holloway, G. Wu and S. B. Smith
Texas Agricultural Experiment Station, Uvalde 78801, USA.

Nonpregnant yearling Brahman (n = 12) and Angus (n = 12) heifers were equally allocated to two dietary treatments in a replicated study to examine responses in lipid metabolism to nutritional treatments consisting of a moderate energy diet (2.0 Mcal ME/kg) fed at maintenance and a 2.5 x maintenance high-energy diet (2.4 Mcal ME/kg) fed for 30 d. In vitro lipogenesis and the activities of lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) were determined in perianal subcutaneous adipose tissue biopsies at the start and end of the trial. At the start of the trial, breeds had similar (P > .10) rates of lipogenesis and LPL activity. Brahman had greater (P < .05) HSL activity than Angus at the start of the trial and tended (P < .07) to have greater HSL activity at the end. Diet did not influence (P > .10) HSL activity. Heifers on the high-energy, higher-intake diet had greater lipogenesis (P < .001) and LPL activity (P < .01) than those on the moderate-energy diet. Inclusion of body condition score (BCS) nested within breed as a covariate explained breed differences for lipogenesis (P < .05). Thus, by including the covariate, the two breeds had similar (P > .10) rates of lipogenesis at the end of the trial. When adjusted for BCS nested within breed, Brahman had greater (P < .05) LPL activity than Angus.