Lipid mobilization in pigs selected for leanness or fatness

Abstract

SUMMARYLipid mobilization was investigated in pigs selected for high and low backfat thickness for four generations. Both epinephrine and pituitary lipid mobilizing factors (LMF) induced in vitro lipolysis in pig fat. The release of non-esterified fatty acids (NEFA) from fat pads sampled from the group selected for thin backfat, the control group, and the group selected for thick backfat differed significantly, the means being 1·16 ± 0·18, 0·83 ± 0·06 and 0·40 ± 0·04 μmol/100 mg per 3 hr respectively.The inhibition by pig serum from the same groups of an LMF- induced adipokinesis in rabbits also differed significantly. The mean NEFA concentrations were, in the same sequence, 5·05 ± 0·15, 3·35 ± 0·27 and 1·29 ± 0·11 milliequiv/litre respectively. A difference in feeding level of about 20% between 25 and 90 kg live weight did not influence lipid mobilization in vitro.The serum inhibition method may be a useful aid to early selection for leanness, since it appears that the method may be used for pigs 5 to 6 weeks old.