Dermatosis in Weanling Rats Fed Lactose Diets I. The Influence of Relative Humidity and Diet

Abstract

A dry scaly dermatosis was observed on the paws of weanling albino rats fed a mineralized milk or purified lactose diets. The maximum degree of scaliness occurred in 10 to 12 days followed by a spontaneous recovery in an additional two to three weeks. The seasonal variation in the degree of dermatosis has been shown to be the result of seasonal changes in the relative humidity of our animal room rather than differences in summer and winter milks. Relative humidities above 50% prevented scaliness; decreasing values increased the severity of scaliness. The purified lactose diets containing corn oil or coconut oil induced the most pronounced scaly dermatosis and diarrhea; replacement of these plant fats with butterfat or lard alleviated the dermatosis and diarrhea. Substitution of sucrose or a galactose-glucose mixture for lactose in the corn oil diet prevented the occurrence of dermatosis and diarrhea. The supplementation of ½ to 1 gm of fresh beef liver per rat per day provided definite protection against the lactose-induced (milk-induced) dry scaly dermatosis when administered within a relative humidity range of 25 to 45%. Liver was more effective as an anti-dermatosis agent when supplemented than when incorporated in the purified lactose diets.