Endocrine Abstracts

Leptin, 16 kDa polypeptide hormone is produced primarily, although not exclusively, by adipocytes. It has been proposed to play a role in neonatal growth and development. The objective of the study was to investigate the effect of chronic leptin administration on the growth performance and endocrine profile of neonatal pigs. Ten Meishan sows gave birth naturally at term and siblings were paired by birth weight and gender. Piglets were subsequently randomly allocated to either leptin (L: n=6) or placebo (P: n=6) group. From day 3 of life the piglets were administered intravenously with either a physiological dose of recombinant leptin (1ml/kg: conc. 50ng/ml) or a saline placebo (1ml/kg) at 10.00 hrs daily for 6 days. Prior to treatment and on day 7 of the study, piglets were weighed to determine body weight (BW) and their body conformation assessed by measuring their crown to rump length (CRL), hind limb length (HLL) and fat free mass per kilogram of body weight (FFM). General Linear Model was used to assess differences between each treatment groups. Prior to the start of treatment, BW, CRL, HLL and FFM were similar (BW: 1.4±0.1 kg; CRL: 25.3±0.7 cm; HLL: 18.1±0.4 cm; FFM: 101.9±5.3 arbitrary units). Daily leptin administration resulted in an increase (P<0.05) in HLL (L, 21.7±0.3; P, 20.5±0.3 cm) and a decrease in FFM (P<0.05) (L, 147.1±6.6; P, 163.4±4.9 arbitrary units) but BW and CRL remained unaffected (BW: L, 2.5±0.1; P, 2.3±0.1 kg; CRL: L, 30.8±0.5; P, 29.8±0.8 cm). Growth rate was also higher (P<0.05) in the leptin group (L, 0.184±0.01; P, 0.122±0.001 kg day-1). In conclusion, the chronic administration of leptin promoted neonatal growth performance with associated changes in their body conformation, which may partly be explained by alterations in nutrient partitioning. However further work is required to fully understand the underlying mechanisms.