Effects of Aureomycin and P 32 on Growth of Young Rats

Summary

1. One group of rats (D), maintained on a Purina fox-checkers diet, ad libitum, injected with 2 μc/g P³² at age 26 days, exhibited weight gain retardation of about 20% compared to a control group (A). 2. Another group of rats (C), injected with 2 μc/g P³² at age 26 days, but fed ground fox-checkers supplemented with 2 mg aureomycin per gram of feed showed no persistent retardation of weight gain, and ultimately attained normal weight. 3. A fourth group of rats (B), fed fox-checkers supplemented with the same quantity of aureomycin, showed initial increase of weight gain; final weight did not differ significantly from the controls. 4. The ratio of weight gain to tibial length increase was the same for rats which received P³² (Group D) and the controls (Group A). P³² (2 μc/g given at 26 days) did not selectively inhibit bone growth. 5. Addition of aureomycin to the diet resulted in an increased ratio of weight gain to tibial length increase compared to the control group (A). Aureomycin (at 2 mg per g of feed) appeared to favor soft-tissue formation rather than a stimulation in general growth.