To further investigate the effect of dietary vitamin A (VA) intake on milk VA concentrations and pup VA status, female rats were fed 2 concentrations of VA [0 (n = 9) or 50 μmol/kg diet (n = 10)] during pregnancy and lactation. Plasma retinol concentrations were significantly higher (30-40%) during lactation than before pregnancy or after weaning but were not influenced by dietary VA. In rats fed VA, VA concentrations during lactation were significantly higher in milk (1.5-3 times), mammary tissue (>100%), liver (4 times), pup plasma (20-40%), and pup liver (1.1-6.7 times). In Expt. 2, when VA intake was switched on d 7 of lactation from 0 to 50 μmol/kg, milk VA concentrations (2.24 ± 0.42 μmol/L; mean ± SD, n = 6) increased signi.cantly (1.7 times) by d 9 to the same level as in rats administered 50 μmol/kg (6.04 ± 0.60 μmol/L; n = 6). When VA was removed from the diet on d 7, concentrations declined significantly (by 50%) and by d 11 were the same as those in rats given 0 μmol/kg. We conclude that the rapid effect of changes in dietary VA intake are attributable to changes in the delivery of chylomicron VA to mammary tissue and milk.
All Science Journal Classification (ASJC) codes
- Medicine (miscellaneous)
- Nutrition and Dietetics