Oxytocin reduces the stress of weaning and increases gastric expression of ghrelin and leptin in neonatal pigs

This study was conducted to determine if oxytocin administration is effective at reducing the magnitude of the post-weaning lag in growth commonly observed in piglets. 220 piglets suckling 20 sows were injected daily with 1mg/kg of either oxytocin or saline from 0–14d. Piglets were weaned at 21d onto either a dry pelleted diet or gruel based diet which was fed for the first week postweaning after which time all piglets received a dry pelleted feed. On d10, 21 and 28 piglets were slaughtered and tissue samples collected for gene expression analysis. At d10 leptin expression was higher in the stomach of oxytocin treated piglets (P=0.028). Oxytocin administration reduced weight loss over the first two days post-weaning (–214 v –293 g/d, P=0.003), which was associated with enhanced expression of gastric leptin (P=0.017) and ghrelin (P=0.016) at 28d of age. No differences in gene expression were observed at 21d. Weaning piglets onto a gruel based diet reduced the magnitude of the post-weaning growth lag (124 v 76 g/d, P<0.001) over the first week post weaning, through increased feed intake (561 v 131 g/d, P