Secondary Deficiency of Vitamin B1 and Riboflavin in the Blacktongue Producing Diet

Thirty-three dogs in 133 attacks of blacktongue were studied in their response to treatment with 1) liver, 2) nicotinic acid alone, 3) adenylic acid from muscle, and 4) nicotinic acid combined with vitamin B1 (thiamin) and vitamin B2 (riboflavin). 1A study of sixty-eight attacks of blacktongue in eleven dogs indicated that liver extract completely supplements the blacktongue producing diet under the conditions of our experiments.2A study of forty-five attacks of blacktongue in fourteen dogs revealed the inability of nicotinic acid to replace liver as a complete supplement to the diet, although in the first and often in the second attack the results with nicotinic acid were comparable to those with liver.3Two dogs were treated with adenylic acid but results were not conclusive.4Twenty attacks of blacktongue in four dogs maintained on the basal diet supplemented with vitamin B1 (thiamin) and vitamin B2 (riboflavin) when treated with nicotinic acid gave results that were in every way comparable with the results obtained with liver. Three dogs were maintained on the basal diet supplemented with these three factors for 11 to 12 months in normal condition. There was no cumulative toxic effect from the nicotinic acid in these three dogs, nor was there any macrocytic anemia in any of the seven dogs. It is concluded then that under the conditions of these experiments both riboflavin and vitamin B1 (thiamin) are secondary deficiencies of our blacktongue producing diet. It appears also that the dog’s requirement for vitamin B1 is markedly increased by repeated attacks of blacktongue.