Effect of vitamin sufficiency on adaptation syndrome in growing rats
The influence of vitamin supply of growing male Wistar rats (n=21) with an initial body weight 53,5Ѓ}0,9 g on their resistance to a single distress induced by the electric shock has been investigated. Control rats within 21 days received a complete semisynthetic diet, providing adequate amounts of vitamins. Combined vitamin deficiency in experimental rats was caused by 5-fold decrease of vitamin mixture amount in the feed and the total vitamin E exclusion from the mixture.
On the 21st day, one day before the end of the experiment, both groups of rats were subjected to stress impact (electrocutaneous irritation on paws, 0,4 mA for 8 sec) and then animals were placed in metabolic cages to collect urine. By the end of the experiment, the animals with the combined vitamin deficiency lag behind in growth. Vitamin B2, A, B1 and E liver content decreased in experimental rats by 1,6, 2,3, 4,4 and 15 fold accordingly. Retinol plasma concentration was significantly reduced by 18%, α-tocopherol level – by 5 fold, urinary excretion of riboflavin and 4-pyridoxic acid (vitamin B6 metabolite) was significantly reduced by 6,5 and 2,46 times accordingly. MDA blood plasma concentration and the urinary ratio of oxidized and not oxidized form of 8-hydroxy-2’-deoxyguanosine did not differ in both groups of rats. Urinary excretion of stress biomarker corticosterone in rats with combined vitamin deficit was 2,5-fold higher than in control rats. Thus, reducing of vitamins supply resulted in an increase of urine corticosterone in stressed rats, that characterized the intensity of general adaptation syndrome. This fact shows the importance of optimal sufficiency with vitamins in nonspecific (general) resistance to stress.
Keywords:vitamin deficiency, stress, electrocutaneous irritation, corticosterone, rats