Kenji Ichinoe

Effects of ageing and gonadal steroid hormones on prolagtin concentration in the anterior pituitary of the chicken

1. Effects of ageing and gonadal steroid hormones on pituitary prolactin (PRL) concentration in the chicken were investigated. 2. No difference was found in the qualitative electrophoretic patterns of the anterior pituitary homogenates at different ages and between the sexes. 3. Pituitary PRL concentrations in males were generally higher than in females. 4. Pituitary PRL concentrations in castrated immature cockerels were higher than in intact birds, while PRL concentration was depressed by the injection of testosterone propionate or oestradiol benzoate. 5. Prolactin concentration in intact immature cockerels was decreased by daily injection of testosterone or oestradiol for 3 weeks but not by injection of the hormones for 1 week.

Studies on the Growth-Promoting Effect of Diethylstilbestrol on the Cockerel

The aim of these studies is to prove the practical effect of diethylstilbestrol (DESE) on cockerels to be raised as broilers. Nowadays, in Japan, cockerels are generally raised as broilers. In the case of White Leghorns, feed utility decreases extremely after 90 days of age. From an economical point of view DESE should be administered at the possible earliest period after birth. The authors examined effects of several combinations of injection times as well as one-time administration of whole dose. The resultsobtained are summarized as follows.1) The proper time of injection in White Leg horns was between 50 and 55 days of age (Tables 3 and 4). The younger a cockerel, the more divided dosage was effective for growth.2) The weight ratio increased in the liver and decreased in the heart and testicles, as was the case in the previous experiment. The more times the dosage of DESE was divided the longer the testicles remained in the juvenile state. But the injection car ried out too many times needed much time and caused lots of shock in chickens. The suitable number of times of injection was at most two.3) Quantity of meat was rather increased by injection, with no significant difference among the methods of treatment. The breast muscle increased as a result of injection, but the thigh muscle rather decreased.4) Little difference was found in meat Composi tion between the injected and untreated control birds. There was a great deal of fat deposition in the in jected cockerels.