Effect of Antibiotics on Growth of Lactose-Fed Rat

Abstract

Summary

Rats fed a diet with a lactose content similar to human milk (43% of the calories) grow at a reduced rate. Normal growth was attained with an equivalent mixture of glucose and galactose, thus implicating the intact disaccharide and suggesting that the adverse effect is of intestinal bacterial origin. Chlortetracycline, and penicillin to a lesser degree, increased growth rate. Carbomycin, bacitracin, polymixin, sulfathalidine and a dihydrostreptomycin-polymixin-pectin-adsorptive clay mixture were ineffectual despite their relatively low solubility. The characteristic low-body fat of the lactose-fed rat was not affected by chlortetracycline administration.