Development and Cure of 'Ring-tailed' Condition in Rats on Vitamin B6 Deficient Diets

In the course of an experiment in which sheep and cow rumen contents were being assayed for vitamin B6 by a modification of the method of Dimick and Schreffler1 we observed, in addition to the usual dermatitis of the face, ears and paws, ring-like (see plate I) lesions on the tail. This condition was first noted after the rats had been on the depletion diet for a period of 5 to 6 weeks and it developed in about 10 out of 100 animals used during the depletion period of approximately 7 weeks.The basal diets used had the following composition:In the first assay, using diet A. factor II was supplied by feeding 0.5 cc daily of a liver filtrate concentrate prepared from Lilly Liver Extract Powder 343∗ by 5 treatments with fuller's earth after the method of Lepkovsky, Jukes and Krause.3 The filtrate secured by this procedure was further treated with 8 volumes of 95% ethanol and the resulting precipitate was discarded. The final filtrate was concentrated under reduced pressure to the point where 1 cc represented ...