Vitamin E and selenium plasma concentrations in weanling pigs under field conditions in Norwegian pig herds

Plasma levels of both vit E and Se were followed in weanling pigs under field conditions in six Norwegian pig herds. Plasma vit E and Se were measured in 3 sows from each herd and 4 piglets in the litter of each sow at the day before weaning (day -1); and in the same piglets at days 4, 8 and 18 after weaning.Mean plasma vit E was 4.0 μg/ml in the sows and 2.6 μg/ml in the piglets at day -1, fell to 1.6 μg/ml in the weanling pigs at day 4, and remained low. Mean plasma Se was 0.22 μg/g in the sows and 0.08 μg/g in the piglets at day -1, rose to 0.10 μg/g in the weanlings at day 4, and continued rising.The results suggest that vit E and Se supplementation to piglets and weanling pigs in Norway may still be suboptimal, but that levels of the two nutrients partially compensate for each other in the weaning period.In feeding experiments with weanling pigs, a number of authors have observed a drop in vit E concentrations in the plasma of pigs in the first weeks after weaning [1-3]. Because vit E and Se status have been shown to influence immunological functions and disease resistance in pigs [4,5], these observations have attracted considerable attention in the pig industry. The fall in vit E has been related to low activity of carboxylester hydrolase enzymes in the gut of weanling pigs [6]. Because these enzymes cleave the dl-α-tocopheryl acetate form of the vitamin used in standard commercial feeds, the use of special supplements for weanling pigs containing non-esterified d-α-tocopherol has been advocated [7]. Other authors conclude that adequate plasma vit E levels in weanling pigs may be attained with sufficient dl-α-tocopheryl acetate in the feed [8].In spite of the strong physiological interrelationship between vit E and Se, only some of the studies on post-weaning vit E levels have included Se measurements, and the Se status of the piglets has hardly been drawn into the discussion about additional vit E supplementation. Studies concentrating on Se only have found