Chlorotetracycline and Growth Promoting Effect of Beta Carotene and Vitamin A in Rats. ∗

Summary

Addition of chlorotetracycline to a Vit. A-deficient diet was found to stimulate additional growth in Vit. A-deficient rats that received restricted intakes of beta carotene or Vit. A. Extent of additional growth depended on amount of the antibiotic incorporated in the basal diet and amount of the supplementary vitamin fed. Under the conditions of the experiments reported a diet that contained 1 g/kg of chlorotetracycline exerted the greatest growth-stimulating effect in rats that subsisted on a minimum maintenance intake of Vit. A or beta caratene. This increase in growth ranged from 200ioJo in the low Vit. A-intake animals to essentially no increase in growth rate of animals that received the higher doses of the vitamin. Food requirement per unit of weight increase was lower in the rats that received the chlorotetracycline-containing diets. Rats restricted to equal food intakes made greater gains in weight when the diet contained the antibiotic.