Utilization of analogues of riboflavin for growth and survival of the chicken.

Groups of normal 5-day-old chicks of the Single Comb White Leghorn strain were fed diets containing no riboflavin, riboflavin, or one of several analogues of riboflavin, to explore differences between the classes Mammalia and Aves. It was found that 7-ethyl-8-methyl-flavin was a suitable replacement for the vitamin. 7-Methyl-8-ethyl-flavin permitted early growth of the chicks, but it did not allow survival when fed in place of riboflavin. The inability to utilize 7-methyl-8-ethyl-flavin represents a real difference in the utilization of flavin between the classes Mammalia and Aves. Other flavin analogues supported some growth, but the chicks did not survive. All groups showed better growth responses than was shown by the riboflavin-deficient group.