Effect of riboflavin status on nitrogen retention during energy restriction and repletion in the rat

Abstract

Nitrogen balances and tissue nitrogen levels of riboflavin deficient and supplemented male Sprague Dawley Crl:Cd rats were compared during successive changes in energy intake while the intakes of protein and other essential nutrients remained constant. The riboflavin deficient diet was fed for three weeks before and continued during four weeks of energy restriction and the subsequent two weeks of energy repletion. Body and organ weights, nitrogen balances, and liver and gastrocnemius nitrogen were unaffected by riboflavin intake except during energy repletion, when the riboflavin deficient rats gained significantly less weight (32.9±5.0 vs 55.8±5.0 g) and retained less nitrogen (91.6±7.5 vs 125.3±7.4 mg/24 h) than their controls restricted to the same level of energy intake. The effect of riboflavin status on nitrogen retention appeared to be secondary to its effects on food consumption and energy utilization.