Correction of the combined vitamin deficit in growing rats fed fiber enriched diets with different doses of vitamins
The effect of 5% dietary wheat bran (WB) on the correction of combined vitamin deficiency by two doses of vitamins (physiological and enhanced) has been analyzed using a rat model (8 groups, n=8/group). Vitamin deficiency in male weanling Wistar rats (58,1Ѓ}0,5 g) was induced by 5-fold reduction of vitamin mixture amount in the feed and complete vitamin E, B1 and B2 exclusion from the mixture for 30 days, then deficit was corrected within 5 days. Rats from control group were fed a complete semisynthetic diet containing microcrystalline cellulose 2%. Vitamin deficient diet for 35 days resulted in reduced (p<0,05) levels of vitamin A in the liver by 25 fold, vitamin E and B1 – 2,0–2,3 fold, vitamin B2 – by 40%, 25(OH)D blood plasma concentration – by 21% compared with the control. Feed consumption of the animals treated with vitamin deficient diet and WB was higher by 43% than in rats with vitamin deficit. Their rate of weight occupied the intermediate position between the rates of weight in deficit and in control animals, and they could not serve a full control to evaluate the WB impact on vitamin sufficiency. After filling the vitamin diet content to an adequate level vitamin E liver content was fully restored. To restore vitamins B1 and B2 liver level higher doses of vitamins (120–160% of adequate content) were required, and to restore the reduced levels of vitamin A in rat liver even 2-fold increased dose of vitamin A was insufficient. The diet enrichment with WB had no effect on vitamin B1 and B2 liver content, regardless of the amount of vitamins in the diet.
Adding fiber to the diet of animals adequately provided with vitamins resulted in significantly 1,3-fold increase of 25(OH)D blood plasma concentration and a slight but significant decrease of α-tocopherol liver level by 16% as compared to rats not receiving WB. The enrichment of rat diet with dietary fibers worsened restoration of the reduced vitamin E status not only by filling vitamin content in the diet to an adequate level, but also by using 2-fold enhanced dose of vitamin.
Within 5 days deficiency of vitamins A, B1, B2 was not eliminated with increasing vitamin diet content to an adequate level. Higher doses of vitamins are needed for the complete correction of vitamin status. The addition of vitamins to an adequate level was sufficient to normalize the elevated liver levels of MDA in rats with combined vitamin deficiency that may be associated with vitamin E status improvement. The diet enrichment with fiber did not affect on the intensity of lipid peroxidation in rat liver regardless of their provision with vitamins.
Keywords:alimentary combined vitamin deficiency, fiber, vitamins, MDA, wheat bran, liver, blood plasma, rats