Studies on Nicotinic Acid Deficiency in the Chick*

In a previous report (I) it was demonstrated that chicks receiving purified rations low in nicotinic acid grew poorly and developed a typical chick blacktongue. The occurrence of these symptoms was prevented by the addition of nicotinic acid to the ration. This paper presents further studies on this deficiency and gives data on the activity of several nicotinic acid esters, as well as studies on the possible synthesis of nicotinic acid within the chick. The experimental procedure and the composition of the basal ration have been reported (1). Briefly, the nicotinic acid-deficient ration is composed of purified casein, gelatin, dextrin, salts, soy bean oil, cystine, crystalline vitamins (except nicotinic acid), vitamins A and D, and concentrates of biotin and the unknown vitamins. The nicotinic acid content of this basal ration varied between 0.2 and 0.3 mg. per 100 gm. Day-old white Leghorn chicks were used throughout. Nicotinic acid assays were made according to the method of Snell and Wright (2). The tissues were prepared by autoclaving at 15 pounds for + hour with 1 N sodium hydroxide. The nicotinic acid content of the whole chick was determined by hydrolyzing the entire animal in boiling 10 per cent potassium hydroxide (alcoholic) for 45 minutes and analyzing a representative aliquot. Coenzyme I analyses were made by the method of Axelrod and Elvehjem (3).