INVESTIGATIONS ON THE EFFECT OF DIFFERENT VITAMIN-B-6 SUPPLY ON VITAMIN-B-6 STATUS (PYRIDOXINE, PYRIDOXAL AND PYRIDOXAMINE) IN LIVER AND BODY OF LACTATING RATS

Eighty female Sprague-Dawley rats were fed a semisynthetic diet during gravidity which was supplemented with 5 mg vitamin B-6 per kg diet. T he daily food intake was 14 g. During the following lactation the rats were assigned to one of 10 vitamin B-6 treatment groups (0, 3, 6, 9, 12, 15, 18, 36, 360 and 3 600 mg per kg diet). The feed was given ad l ibitum. At day 14 of lactation the rats were decapitated. Parameters f or determination of the vitamin B-6 status were concentration of pyrid oxine, pyridoxal and pyridoxamine in liver and body analyzed by using HPLC. Body was defined without the gastroenteral tract that was divide d into carcass (extrahepatical compartments without liver) and total b ody (extrahepatical compartments plus liver). The mean weight of liver was 13 g with a dry mass of 33 %; there was no difference between the treatment groups. The vitamin B-6 concentration was lowest in rats fe d 0 mg vitamin B-6/kg diet (5 mu g/g fresh matter, FM) and highest in the rats fed 3 600 mg vitamin B-6/kg diet (10.9 mu g/g FM). The total vitamin B-6 consisted on the average of 38 % pyridoxal and 62 % pyrido xamine. This was only changed significantly at the highest supplementa tion level, where 20 % pyridoxine were detected instead of pyridoxamin e. The mean weight of carcass averaged 212 g at a dry matter content o f 31 %. The vitamin B-6 concentration ranged in the treatment groups f rom 0 mg to 360 mg vitamin B-6/kg diet between 2.1 mu g/g FM and 2.8 m u g/g FM. It was highest in the 3 600 mg vitamin B-6 treatment group a t 7.5 mu g/g FM. The total vitamin B-6 consisted of 63 % pyridoxal and 37 % pyridoxamine. It was only significantly affected in the 3 600 mg vitamin B-6 treatment group, where also pyridoxine could be found in the amount of 56 %. The results indicate that alimentary vitamin B-6 s upply had more influence on liver vitamin B-6 concentration than on ca rcass concentration. Total body concentration is very similar as carca ss concentration, as 95 % of vitamin B-6 is located there. The suitabi lity of the parameters for the evaluation of the vitamin B-6 requireme nt was confirmed by the comparison of two statistical methods. It is c oncluded that a vitamin B-6 supply of 5 to 6 mg/kg diet is necessary t o meet the requirements during lactation.