Riboflavin Studies with Pigs

Abstract

Three experiments were conducted to gain information concerning the riboflavin requirement of the growing pig. Purified diets of a similar nature were used in all experiments, and all pigs were individually fed ad libitum in wire screen-bottomed cages. A riboflavin depletion period preceded the experimental treatments. In the first experiment, three groups of 6 pigs each received diets containing 0.05, 0.85 and 1.45 mg. of riboflavin per lb. Final weights and feed consumption of pigs on the two higher levels did not differ significantly but were highly significantly greater than for pigs on the low level. When adjusted for feed consumption, final weights of pigs on the higher levels were still significantly (P less than 0.01) above the low level. Adjusted daily gains for the above 3 treatments were 0.12, 1.58 and 1.39 lb., respectively. In the second experiment, three groups each of 6 pigs received diets-containing 0.65, 0.85 and 1.05 mg. of riboflavin per lb. No significant difference was found in final weights or feed consumption. Adjusted average daily gains for the three treatments were 1.47, 1.45 and 1.47 lb., respectively. The third experiment was conducted to determine the effects of chlortetracycline and vitamin B12 supplementation upon the riboflavin requirement of the pig. A suboptimum level of 0.4 mg. and an optimum level of 1.2 mg. of riboflavin were fed with and without 10 mg. of chlortetracycline and with and without 15 meg. of vitamin B12, each per lb. of diet. The 0.4 mg. level of riboflavin was clearly suboptimal, the difference in final weights due to this factor being highly significant. However, after adjusting for differences in feed consumption the riboflavin effect was not significant, indicating that a major portion of the pig's response to riboflavin is related to voluntary feed intake. Chlortetracycline caused a significant increase in gains during the first half of the experiment, though not significant after adjustment for feed consumption. There was no significant interaction. Thus, vitamin B12 and chlortetracycline supplementation did not significantly influence the riboflavin requirement of the pig. The riboflavin requirement of the growing pig is between 0.4 and 0.65 mg. per pound of diet when the mean environmental temperature is 53° F.