Stokstad (1943) isolated folic acid as a result of investigations of the properties of factors present in yeast or liver that would promote the growth of lactic acid bacteria. Subsequent studies demonstrated that the active factor was identical to, or related to, antianemia factors and animal growth factors discovered by other investigators. Mowat et al., (1948) showed that folic acid is composed of a pteridine ring linked through a methylene bridge to p-aminobenzoic acid to form pteroic acid, which is in turn linked as an amide to glutamic acid. Early studies of the ability of purines or thymine to partially satisfy bacterial requirements for folic acid pointed to the involvement of this vitamin in purine and thymine biosynthesis. Early studies using 14 C-labeled formate and formaldehyde suggested a role of folic acid in the metabolism of one-carbon units.
Folic acid deficiency in chicks is characterized by poor feathering, anemic appearance (waxy white comb and pale mucous membranes in the mouth), lethargy, reduced feed intake, slow growth, and abnormal skeletal development leading to perosis.
