Muscle and adipose tissue lipoprotein lipase in fetal and neonatal swine as affected by genetic selection for high or low backfat.

The effect of genetic selection for backfat accumulation on adipose tissue and muscle lipoprotein lipase (LPL) in fetal and neonatal pigs was investigated. Fetal pigs at 110 d of gestation were taken surgically from sows of either a high backfat (High) or low backfat (Low) line of Yorkshire pigs selected over 18 generations on the basis of backfat thickness at 80 kg live weight. Fetuses of Yorkshire (Control) and Ossabaw (Obese) sows were used for comparison. Activities of LPL/mg cytoplasm protein in subcutaneous adipose tissue were 2.23 +/- .19, 3.98 +/- 1.06, 6.37 +/- .83 and 7.57 +/- .66 nmol FFA released/min and LPL/g tissue was 34.80 +/- 4.06, 58.36 +/- 14.23, 99.55 +/- 15.15 and 159.94 +/- 9.7, for Low, Control, High and Obese 110-d fetuses, respectively. Muscle (semimembranous) LPL/mg protein was 1.06 +/- 1.17 and 1.39 +/- .20 and LPL/g tissue was 50.11 +/- 6.9 and 59.07 +/- 9.12 for High and Low line fetuses, respectively. Fetal body composition was not different for High and Low lines. In 14 d-old suckling pigs, adipose tissue LPL/mg protein had increased to 18.09 +/- 3.48 and 17.76 +/- 3.98 and LPL/g tissue was 291.12 +/- 56.60 and 308.45 +/- 64.43 in High and Low line pigs, respectively. Muscle LPL/mg protein had decreased to .83 +/- .08 in High and 1.25 +/- .13 in Low line pigs, while LPL/g muscle was similar between these lines. These effects of genetic selection on muscle and adipose tissue suggest that early in development, the partitioning of nutrients to lean of fat tissues may be altered, eventually leading to a marked difference in body composition.