Effects of weaning conditions on the evolution of piglet plasma concentration of vitamin E

Weaning causes oxidative stress in piglets. Endogenous and exogenous vitamin E (vit E) participates to theneutralization of pro-oxidant molecules in the organism. This study aimed to analyze the effect of weaning conditions on the evolution of plasma vitamin E concentration on piglets. In trial A, piglets born from 12 litters were weaned at either 21 (W21) or 28 (W28) days of age in optimal (OC) or deteriorated (DC) conditions (n=16 per group). Piglets from OC group originating from 2 litters were housed by 4 (0.39 m2/pig) in cleaned and disinfected pens. Those from DC group originating from 4 litters were housed by 8 (0.20 m2/pig) in dirty pens after a waiting time of 4 h at 20 °C. From 12 to 61 days of age, blood was collected and pigs were weighed weekly and then at 88, 119 and 147 days of age. In trial B, piglets (n=288 from 144 sows) from 16 commercial farms were weaned at 28 days of age. Blood samples were collected when piglets were 26- (on sows and piglets) and 33-days old (on piglets only). In both trials, weaning led to a dramatic drop of the plasma concentration of vit E (P<0.001). In trial A, this drop was similar whatever the age at weaning or housing conditions (P>0.05). After weaning, vit E concentration remained stable until 147 days of age. In trial B, piglet plasma concentration of vit E at 26 days of age was not associated with lactating sow vit E concentrations (P>0.05) and was different between farms (P<0.001). The higher plasma concentration of vit E before weaning could be explained by the high vit E content in colostrum and milk leading to the saturation of body fat reserves of the piglet. At weaning, the high requirements of vit E for antioxidant purposes as well as low feed intake, lower fat content of the feed compared to milk and lower activity of enzymes involved in vit E absorption could explain the dramatic drop of plasma vit E. The relatively low concentrations of vit E until slaughter age could reflect an incomplete reconstitution of body reserves. To conclude, weaning led to a drop of plasma concentration of vit E whatever the weaning conditions indicating dramatic changes in vit E statusand metabolism at weaning.