Transfer of maternal haptoglobin to suckling piglets

Abstract

The acute phase protein haptoglobin (Hp) exerts immune modulating functions in the innate and adaptive immune system. In pigs, serum Hp concentrations are linked to impaired growth performance. There is little information on Hp in newborn piglets and the onset of endogenous Hp synthesis. In the first experiment we analyzed Hp concentrations in colostrum from sows (n=5) and serum from their off-spring (n=43) during the first 12h of life. The piglets were divided in a colostrum group which was allowed to suckle and a colostrum-deprived group which received a Hp-free milk replacer. We were able to show that serum Hp in newborn piglets increased 3h after colostrum intake whereas serum Hp remained low in colostrum-deprived littermates. The absorption of colostral Hp in the jejunum could be shown via immunohistochemistry. In colostrum suckled piglets, endogenous Hp synthesis in the liver increased 9h after birth, no increase in Hp mRNA was observable during the first 12h of life in colostrum-deprived piglets. From our results we concluded that maternal Hp is transferred to newborn pigs via colostrum and the stimulus for the increase in Hp synthesis is mediated by colostrum. In a second experiment we analyzed Hp in colostrum, milk and serum from sows (n=43) and their off-spring (n=442) from birth until weaning. Haptoglobin was high in colostrum (1.11 ± 0.10mg/ml) and declined to lower but stable milk levels (0.36 ± 0.08 mg/ml) until weaning. Colostral Hp and daily litter weight gain were negatively correlated (r=-0.5, p<0.01) whereas the relationship between piglets serum Hp and daily weight gain was weaker (r=-0.22, p<0.05). We therefore speculate that maternal Hp exerts systemic actions in piglets.