Abstract
1. Niacin was eliminated from the basal diet devised by HALVER et al., and the requirement of young carp for the vitamin was studied.
2. In two feeding trials lasting respectively for 8 and 10 weeks, the deficiency symptoms were characterized by poor growth, loss of appetite, hemorrhage in the skin, and high mortality.
3. When the niacin-deficient group was divided, the section receiving the complete diet indicated the recovery of growth and disappearance of the deficiency syndromes.
4. Under the experimental conditions adopted, the requirement for niacin was found to be 2.8mg per 100g of diet or 0.55mg per kg of body weight per day according to the body weight gain.
