[Comparison of vitamin B6 status of gravid and nongravid rats with varying vitamin B6 supplements].

In a two-factorial experiment the influence of graded vitamin B6 supplements on the vitamin B6 status of pregnant and nonpregnant rats was examined. Additionally the question concerning a vitamin B6 super-retention in pregnancy should be investigated. The experiment was carried out with 69 female SPF-Sprague-Dawley rats. Nine rats served as controls and were killed at the beginning of the experiment. On the first experimental day half of the remaining animals were mated at an average body weight of 210 g. The rats were then divided into five dietary groups, each containing 6 gravid and 6 nongravid animals. Throughout the experiment the rats received a semisynthetic casein-starch diet, containing 1, 6, 12, 24, and 48 mg vit. B6/kg respectively. The trial ended at day 19 of pregnancy. Liver, right and left gastrocnemius muscle and the remaining carcass (without the intestinum and the reproductive product of the pregnant animals) were microbiologically analysed for their vitamin B6 contents. The vitamin B6 status of the liver, which contained an average of 8.4 micrograms vit. B6/g fresh matter (FM) was not influenced by pregnancy. In muscle and carcass, however, pregnancy caused significantly reduced vitamin B6 levels of 4.8 and 2.6 micrograms vit. B6/g FM. Compared to the concentrations of the nongravid animals the values of the gravid rats were decreased by 6 and 7% respectively. The vitamin B6 supply of 1 mg/kg diet caused significantly lowered vitamin B6 concentrations in muscle and carcass of all animals. Intake levels of more than 6 ppm vitamin B6, however, did not further improve the vitamin B6 status of these organs. The carcass was only poorly affected by the vitamin B6 supplementations. Significant differences in vitamin B6 concentrations were only found between the 1 and 48 ppm vitamin B6 treatment. The whole vitamin B6 pool of the maternal organism, except the reproductive product, decreased in pregnancy from an average of 651 to 596 micrograms vitamin B6. Because of these results a super-retention could not be proved for vitamin B6. Moreover, a recommendation for the optimal vitamin B6 requirement in pregnancy was derived from the present results. Accordingly a supply of 6 mg vit. B6/kg diet, equivalent to a daily intake of 80 micrograms vitamin B6, is thought to be adequate to ensure an optimal vitamin B6 status in pregnant rats.