Lactating Sows and Suckling Piglets Preferentially Incorporate RRR- over All-rac-α-Tocopherol into Milk, Plasma and Tissues
2002
Lauridsen, Charlotte | Engel, Harold | Jensen, Soren K. | Craig, A Morrie | Traber, Maret G.
Synthetic vitamin E, all-rac-α-tocopherol, contains eight different stereoisomers, only one of which, RRR-α-tocopherol, occurs naturally. The objective of this investigation was to evaluate the relative abilities of these two vitamin E forms to enrich piglet tissues when fed as α-tocopheryl acetates to sows during pregnancy and lactation. α-Tocopherol delivery to fetuses and to suckling piglets was monitored by feeding 150 mg each of d3-RRR-α- and d6-all-rac-α-tocopheryl acetate to three pregnant sows daily from 7 d before to 7 d after giving birth. Labeled and unlabeled vitamin E concentration ratios were measured in sow plasma and milk, and in piglet (n = 9) plasma and tissues at birth, 7 and 21 d. At birth, despite elevated sow plasma deuterated α-tocopherol concentrations, no labeled α-tocopherol was detected in piglet plasma or tissues. Sow plasma and milk d3-α- to d6-α-tocopherol concentrations were 2:1, leading to a 2:1 ratio in suckling piglet plasma and tissues. In piglets at d 7 compared with birth, most tissues contained a 10-fold increase in total α-tocopherol; the highest deuterated vitamin E concentrations were in the liver, followed by the lung, heart, kidney, muscle, intestine and brain. In conclusion, pigs discriminate between RRR- and all-rac-α-tocopherol with a preference for RRR-α-tocopherol; thus, the official bioequivalence ratio of 1.36:1 RRR- to all-rac-α-tocopherol is underestimated. After initiation of suckling, piglet plasma and tissues demonstrated a dramatic increase in vitamin E concentrations, emphasizing the limited placental vitamin E transfer and the importance of milk for enhancing the vitamin E status of the newborn.
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