Effects of L-carnitine in the gestating sow diet on fetal muscle development and carcass characteristics of the offspring^1,2

A total of 232 sows were used to determine the effects none or an additional 50 ppm of L-carnitine in the gestation diet on sow and offspring performance. Sows were fed dietary treatments from breeding until d 110 of gestation. Offspring from sows were ear-notched according to maternal treatment at birth and carcass data were obtained at slaughter. Sow plasma IGF-I concentration was similar (P>0.10) between control and L-carnitine supplemented sows on d 30 and 60 of gestation at 2 h after feeding. No differences were observed in either the immediate or subsequent number of pigs born per litter. No differences were observed in a sub-sample (n = 181) of pig weight at birth, weaning or d 59 of age between control and treatment offspring. Analysis of newborn pigs revealed no differences in semitendinosus cross-sectional area or primary (slow-twitch, red) fibers. Offspring of sows fed L-carnitine had a numerical tendency (P = 0.11) for a lower ratio of secondary:primary fibers compared with offspring of control sows. No differences were observed in hot carcass weight (87.6 kg); however, loin depth (57.0 vs 59.4 mm; P < 0.01) and percentage lean (54.45 vs 55.10; P < 0.01) were increased, and backfat decreased (18.4 vs 17.8 mm: P < 0.01) in offspring of sows fed L-carnitine during gestation. Therefore, while feeding L-carnitine during gestation had no effect on the number of pigs born, it improved carcass leanness of the offspring at market weight and tended to lower ratio of secondary:primary fibers at birth.