Riboflavin deficiency would be more prevalent in dog diets compared to cat diets, as more riboflavin-poor cereal grains form a higher percentage of dog diets. Riboflavin fortification levels should be adjusted, especially to offset the exclusion or reduced amounts of riboflavin-rich ingredients such as milk fermentation and fish and meat by-products. Riboflavin deficiency will not occur if the diet contains meat or dairy products (Watson, 1998).
While it is unlikely that a clinical riboflavin deficiency would be seen in cats today, it is not impossible for it to occur in dogs. There are still a number of hunt clubs, kennels, etc., formulating their own rations rather than purchasing commercial foods. It is in these situations that a deficiency state would most likely occur (Ralston Purina, 1987). If dogs are observed with weight loss, malaise, gastrointestinal disturbances, dermatitis, stomatitis, conjunctivitis and cataracts, a deficiency of riboflavin might be included in the differential diagnosis.
Riboflavin is remarkably stable during heat processing. However, considerable loss may occur if foods are exposed to light during cooking, and some losses occur in feed administered to animals out of doors. Only that portion of riboflavin in the feed exposed to light would be destroyed; therefore, this may be of little significance for pet foods. Up to 26% of riboflavin present in pet food is lost during extrusion (Hoffmann-La Roche, 1981).
In dry form, riboflavin is extremely resistant to oxidation, even when heated in air for long periods. Under typical circumstances, riboflavin has good stability when added to mixed feeds (Hoffmann-La Roche, 1969). Riboflavin is quite stable in multivitamin premixes (Frye, 1978). A recent report demonstrates a 98% retention of riboflavin after six months in a vitamin premix; however, the retention was only 59% when the premix contained choline and trace minerals (Gadient, 1986).
