An evaluation of natural (RRR-α-tocopheryl acetate) and synthetic (all-rac-α-tocopheryl acetate) vitamin E fortification in the diet or drinking water of weanling pigs1,2,3

Abstract

Three experiments conducted with weanling pigs evaluated the effects of vitamin E added to the drinking water or diet on plasma and tissue alpha-tocopherol concentrations. When natural or synthetic vitamin E was used, it was added at an IU-equivalent basis, but natural vitamin E was 73.5% (mg basis) of the synthetic vitamin E. Experiment 1 used 18-d-old weanling pigs (n = 120) in a 3 x 2 factorial arrangement of treatments in a randomized complete block design with 4 replicates. The first factor evaluated the dietary levels of natural vitamin E (RRR-alpha-tocopheryl acetate) added at 0, 50, or 300 IU/kg, whereas the second factor was the natural vitamin E added to the drinking water at 0 or 100 IU/L. Pigs were bled at periodic intervals, and 1 pig per pen was killed at the end of the 21-d trial and tissues (liver, heart, lung, and loin) were collected for alpha-tocopherol analysis. When vitamin E was not added to the diet or water, plasma alpha-tocopherol declined over the 21-d period. Although there were some interactions (P < 0.01), tissue and plasma alpha-tocopherol concentrations increased linearly when vitamin E was added to the diet or water. Experiment 2 was a 3 x 2 factorial in a randomized complete block design with 4 replicates. A total of 96 pigs weaned at 18 d of age, with an initial BW of 6.2 kg, were fed a nonvitamin E fortified diet, but natural or synthetic (all-rac-alpha-tocopheryl acetate) vitamin E was added to their drinking water at 50, 100, or 150 IU/L. Pigs were bled at 0, 3, 7, 10, 14, and 21 d postweaning, with tissues (liver, lung, heart, and loin) collected for alpha-tocopherol analysis at d 21. The results indicated that plasma alpha-tocopherol concentrations increased (P < 0.01) as vitamin E increased, with greater tissue alpha-tocopherol concentrations (P < 0.01) when natural vitamin E was provided. Experiment 3 was conducted in 2 replicates, but pigs (n = 60) were not provided vitamin E in the diet or water for 7 d postweaning, and then natural or synthetic vitamin E was added to the drinking water as in Exp. 2 (50, 100, or 150 IU/L). Pigs were bled at 0, 2, 4, 6, 8, 10, and 24 h after being provided vitamin E to evaluate the absorption from each vitamin E source and level. Plasma alpha-tocopherol increased quadratically (P < 0.01) and plateaued at 8 to 10 h for each treatment group. These results indicate that adding vitamin E to the pig's water supply at weaning was more effective in increasing plasma alpha-tocopherol than when it was added to the diet during the initial 14 d postweaning, and that natural vitamin E was a superior source compared with synthetic vitamin E.

Effects of oral micellized natural vitamin E (d-α-tocopherol) v. synthetic vitamin E (dl-α-tocopherol) in feed on α-tocopherol levels, stereoisomer distribution, oxidative stress and the immune response in piglets

“…These results would corroborate that the equivalent dose of the natural form in water to the synthetic form in feed is 1 : 3. Hence, our results would agree with those reported by Wilburn et al (2008) as water to feed ratio ⩽ 2 : 1.…”

“…This has been widely reported in the literature and is attributed to increased stress (Lauridsen et al, 2002;Moreira and Mahan, 2002;Wilburn et al, 2008). However, it is interesting to note that the magnitude of the decrease was greatest in groups with higher serum concentrations of α-tocopherol at weaning (P < 0.001, interaction time × treatment; Table 3).…”

“…Moreover, as expected, sow serum α-tocopherol concentration increased with supplementation time (P < 0.001; Table 2) with it being interesting to note that the increase was higher when sows were supplemented with the natural vitamin E (contrast 3: interaction time × source, P < 0.001), mainly with 1/3-NAT (contrast 4: interaction time × dose: P = 0.011). Other authors have previously demonstrated that natural vitamin E was a superior source compared with synthetic (Chung et al, 1992;Mahan et al, 2000;Yang et al, 2009) and that the supplementation was more effective in increasing serum α-tocopherol when administered in the water supply than when it was added to the diet (Wilburn et al, 2008). Moreover, micellized natural vitamin E is better absorbed in plasma because micelles that transport vitamin E solubilized in their core (Pumfrey et al, 1993;Pagan et al, 2005).…”

“…As micellized natural vitamin E (D-α-tocopherol) was expected to be more efficiently accumulated than the synthetic form (Pumfrey et al, 1993;Pagan et al, 2005) and that water consumption would be more consistent than feed intake during the post-weaning period (Wilburn et al, 2008), we designed various strategies to study the effectiveness of supplementing piglets and/or sows with vitamin E. Supplementation ratios to piglets and/or sows were 1 : 1, 1 : 2 and 1 : 3 (natural vitamin E in water: synthetic in feed) trying to find a real equivalence between both forms of vitamin and administration vehicles that minimize piglet serum α-tocopherol decline after weaning. These ratios were based on previous results (Wilburn et al, 2008) that reported a water to feed ratio ⩽ 2 : 1 when using the acetylated form (synthetic v. natural). Doses were close to or under the range of minimum daily vitamin E requirement for pregnant sows (44 IU/kg) and piglets (11 IU/kg) recommended in the NRC guidelines (NRC, 1998), and therefore higher differences among groups would be expected.…”

“…However, to the best of our knowledge, there is no information in the literature in which a lower dose resulted in higher absorption and serum accumulation. In the unique Natural v. synthetic vitamin E in piglets Amazan, Cordero, López-Bote, Lauridsen and Rey study carried out with supplementation in drinking water, Wilburn et al (2008) used higher doses (50, 100, 150 ppm) of α-tocopheryl acetate, the accumulation of which depends on the presence of an esterase enzyme present in the digestive secretions. Our results might indicate that under minimal doses, absorption of lower amounts of the micellized alcohol form administered orally (1/3-NAT v. 1/2-NAT) would be more efficiently accumulated.…”