THE RIBOFLAVIN REQUIREMENT OF ADULT DOGS AT MAINTENANCE IS GREATER-THAN PREVIOUS ESTIMATES

A study was conducted to determine the riboflavin requirement of adult dogs at maintenance. Twenty adult mixed breed dogs were fed a semipur ified meal with one of five riboflavin concentrations: Diet 1, 1.7 mg/ kg; Diet 2, 2.7 mg/kg; Diet 3, 3.7 mg/kg; Diet 4, 4.7 mg/kg; and Diet 5, 5.7 mg/kg. The erythrocyte glutathione reductase activity coefficie nt (EGRAC) was used to determine biochemical riboflavin deficiency. Do gs fed Diet 1 had a greater (P < 0.05) EGRAC (1.24) on d 56 of the tri al compared with that of dogs fed Diet 5 (1.11), indicating marginal r iboflavin deficiency in dogs fed Diet 1. On d 84 the mean EGRAC for do gs fed Diet 1 (1.36) was different from EGRAC obtained for dogs fed th e other diets (1.19, P < 0.05). This difference in mean EGRAC was stil l present on d 112 (1.59 vs. 1.27; P < 0.01). There was no difference in d 112 mean EGRAC for dogs fed Diets 2, 3, 4 and 5 (P < 0.05). The b roken line requirement estimate for the adult dog at maintenance was d etermined to be 66.8 mu g riboflavin kg body wt(-1). d(-1) using the d 112 EGRAC as the basis for assessing biochemical riboflavin deficienc y.