The rate of gain of rats fed raw soybean oil meal was 80%, or less, of gains made by rats fed autoclaved meal. The addition of 0.1% procaine pencillin plus 0.1% streptomycin sulfate has resulted in approximately equal rates of gains by rats fed raw and autoclaved soybean oil meal. These results open a new point of attack on understanding the growth inhibitory effects of raw soybean oil meal and, possibly, on the problem of the growth stimulatory effects of antibiotics.
Rats fed raw soybeanoil meal, as the protein source in an otherwise complete ration, grow at a slower rate than animals fed a similar ration containing autoclaved soybean oil meal. This effect was first noted by Osborne and Mendel (24) in 1917. The same effect on the growth rate of swine was reported by Hayward, Bohstedt, and Fargo in 1934 (73) and on chicks by Wilgus, Norris, and Heuserin 1936 (32).