Comparative changes in the serum concentrations of inhibin-B, prolactin, gonadotropins and steroid hormones at different reproductive States in domestic Turkey hens.

The present study was undertaken to compare the changes in circulating levels of inhibin-B, prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17beta, progesterone and testosterone during the different reproductive states of turkey hens. Blood samples were collected during different reproductive states, at laying, incubating and out of lay. Inhibin-B was measured by ELISA, while other hormones were determined by Chemiluminescent Microparticle Immunoassay (CMIA). The results revealed highly significant differences among the hen's states for all serum hormone concentrations. The highest levels of inhibin-B and prolactin were observed in incubating hens, while the lowest values were observed in laying hens. In contrast, the highest levels of FSH, LH, estradiol-17beta, progesterone and testosterone were found in the laying group, while the lowest values were found in the incubating group. The progesterone level was higher in the laying group compared with the other groups. These results clearly demonstrate that negative correlation was found between both the inhibin-B and prolactin levels and the gonadotropin and steroid hormone concentrations during the different reproductive states of the turkey hens. In addition, the results suggest that inhibin-B may be involved in control of FSH and LH secretion.