Abstract：Abstract:120 couples of laying pigeons of 720 days of age were randomly divided into four groups, each of which included three replicates of 20 doves. The doves were kept in individual cages and provided with purified diet ad libitum. The difference of control and treatment groups diet was the amount of olanzapine (the diet of control group contained 0 mg olanzapine /kg and the diet of treatment groups contained 0,0.75,1.25mg olanzapine /kg, respectively).The effects of Olanzapine on the expression of PRLR gene were investigated by means of RT-PCR. Supplementation of 1.25 mg/kg Olanzapine decreased the relative mRNA expression of PRLR to β-actin (PRLR/β-actin ratio) by 14.3%（P<0.05）.These results implicated that Olanzapine can significantly increase egg production by inhibiting the expression of PRLR gene from pituitary gland. These results also indicate that hypothalamic DA and 5-HT activities are the vital causes of development and maintenance of broodiness and pituitary PRL secretion.
