Influence of different dietary vitamin B-6 supply during gravidity and lactation on total vitamin B-6 concentration (pyridoxine, pyridoxal and pyridoxamine) in blood and milk

In a two factorial trial with 80 (5 x 2 x 8) Sprague-Dawley rats weighing 257 g the influence of different dietary vitamin B-6 supply on concentration in blood and milk was examined. The two factors were 5 doses of alimentary vitamin B-6 supply during pregnancy (0.6, 3, 6, 18, and 180 mg vitamin B-6 per kg diet) and 2 doses in lactation (3 and 6 mg vitamin B-6 per kg diet). The rats were fed a semisynthetic diet. The daily food intake was 14 g during pregnancy and ad libitum during lactation. At day 7 and 13 of lactation the dams were milked and at day 14 the animals were killed by decapitation. Vitamin B-6 concentration of milk at 7th and 13th day of lactation and vitamin B-6 concentration of blood at 14th day of lactation were examined. The mean total vitamin B-6 concentration in blood was 0.18 mu g/ml and consisted of 94.8% pyridoxal and 5.2% pyridoxamine. An elevation in vitamin B-6 supply during pregnancy led to an increase in blood vitamin B-6 concentration of 40% and the vitamin B-6 treatment during lactation caused an increase of 50%. The mean total vitamin B-6 concentration in milk at the 7th day of lactation was 0.35 mu g/ml and consisted of 79.5% pyridoxal, 15.6% pyridoxamine and 4.9% pyridoxine. An elevation in dietary vitamin B-6 supply during pregnancy led to an increase in milk vitamin B-6 concentration of 79% and vitamin B-6 treatment during lactation led to an increase of 38%. The mean total vitamin B-6 concentration in milk at the 13th day of lactation was 0.44 mu g/ml and consisted of 79.8% pyridoxal, 13.9% pyridoxamine and 6.3% pyridoxine. Milk vitamin Bh concentration was increased by 53% through the dietary supply during pregnancy and by 32% through the higher lactational supply The experiments indicate that vitamin B-6 concentration in blood and milk is a reflection of dietary supply, whereby in lactation milk concentration is less influenced than blood.