Studies on Raw and Heated Unextracted Soybeans for Layers

CARVER et al. (1946) reported that raw extracted soybeans supported excellent egg production in all-mash diets containing 13 percent protein. Fisher et al. (1957), using soybean protein exclusively in a semipurified diet, stated that raw extracted soybeans, properly supplemented with methionine and vitamin B12, would support equally good egg production as heated soybeans. Later, Griminger and Fisher (1960) concluded that egg production and egg weight could be maintained on a practical diet in which the major source of protein was unextracted raw soybeans. Recently, Saxena et al. (1963, a, b) reported no differences in egg production or pancreas size between hens fed raw extracted soybeans supplemented with methionine and hens fed heated soybeans. In contrast, Hill and Renner (1963) observed a reduction in egg production and metabolizable energy values for raw unextracted soybeans and extracted soybean flakes as compared to heated soybeans and soybean flakes. A comprehensive review of the…