In the preceding paper' it was shown that antibody-like factors, endowed with a suppressing power for viruses inducing tumors in the fowl, are present in the blood serum of a great majority of adult chickens, while they are generally lacking in the sera of chicks and pullets. The next logical step was to compare the reaction induced by such viruses injected into the blood stream of chicks with ...

A specific radioimmunoassay technique was used to measure the concentration of oestradiol at weekly intervals in the blood plasma of seven pullets from 7 weeks of age until they were sexually mature. Large differences in oestradiol concentration were observed between birds. The mean concentration was 94 pg/ml plasma 7 weeks before the first egg was laid. The concentration then began to rise sha...

Two studies were conducted utilizing 270 chickens to evaluate the efficacy of yeast culture (YC) for both broiler and layer ayian types. In the first experiment, three dietary levels (0, 1.25, 2.50 percent) of YC were included in a nutritionally complete ration and fed to 14-day-old broiler chicks for 8 days. Body weight gain, feed consumption (g) and feed efficiency were not influenced by yeas...