Effect of gamma irradiation, fractionation, and penicillin supplementation on the rachitogenic activity of rye for chicks.

Experiments were conducted to study the effect of gamma irradiation on the rye-vitamin D antagonism in broiler chicks. In an initial study, the irradiated grain was exposed to gamma rays for 6 hr (2 Mrad) and was fed to rachitic chicks for only 12 hr before a single oral dose of vitamin D3. In another trial, birds were fed during the entire experiment (12 days) on the different experimental diets, and the irradiated grain was exposed to gamma rays for 20 hr. Results indicate that the factor in rye that interferes with vitamin D utilization was largely inactivated by exposing this grain to gamma rays for 20 hr. Additional information is reported in this paper related to the alleviation by extraction or antibiotic supplementation on the rachitogenic properties of rye. These studies were conducted by feeding to rachitic chicks the test materials for only a short period of time (12 hr) before a vitamin D3 oral dose and measuring the bone mineralization 48 hr later. Results indicate that the rachitogenic factor in rye is not present in the ash portion of the grain, that it can be largely overcome by water extraction and penicillin supplementation, and that an organic solvent extraction has no effect. Cooked beans which depress growth and increase the growth response to antibiotics are not rachitogenic.