Abstract
The current study aimed to investigate the potential use of nano-bromocriptine in improving the laying performance of late laying hens by modulating the prolactin gene expression. A total of 150 NOVOgen brown laying hens aged 70 weeks were randomly allocated into three groups of 50 birds each. The first group was kept as a control, while the second and the third groups were treated with bromocriptine and nano-bromocriptine, respectively, at a dose of 100 µg/kg body weight per week. The pause days, egg production, feed per dozen egg, and Haugh unit were determined on a monthly basis. Also, the relative prolactin gene expression in the pituitary gland was quantified using qPCR and the number of the ovarian follicles was determined after slaughtering at the 84th week of age. It was found that nano-bromocriptine and bromocriptine improved egg laying performance with minimal pause days, reduced feed per dozen egg, and depressed the relative prolactin gene expression; however, nano-bromocriptine treatment was significantly effective compared to bromocriptine. In conclusion, nano-bromocriptine might be beneficial for elongating sequences and reducing pauses.