A possible relationship of vitamin B13 to orotic acid.

Novak, Hauge, and Carrick (1) presented evidence that one or more unidentified chick growth factors were present in distillers’ dried solubles (DDS). Novak and Hauge (2) announced the isolation of an unknown growth factor in a relatively high degree of purity from DDS. This substance was very potent in stimulating rat growth and was designated vitamin B13. It has an ultraviolet absorption maximum at 282 rnp and a minimum at 255 rnp. Austin and Boruff (3) have also isolated vitamin B13 from DDS and have shown that it promotes the growth of chicks. Cunha et al. (4) reported that 3 ml. of a vitamin Bla concentrate per 100 pounds of feed stimulated the growth of pigs as much as 50 per cent above the control ration containing an adequate amount of vitamin Blz. Unpublished research conducted in this laboratory (5, 6) has shown that DDS contains the whey factor (7) and a factor necessary for the growth of Lactobacillus bulgaricus. Wright et al. (8) also found the L. bulgaricus factor in DDS and they reported that erotic acid (4-carboxyuracil) could replace any of the natural materials for the growth of L. bulgaricus 09. Since erotic acid has an ultraviolet absorption spectrum (9) similar to that of vitamin B13 (2), it is possible that the two growth factors may be related.