# Active Immunization Against Inhibin Impaired Spermatogenesis, Plasma Luteinizing Hormone, Pituitary Prolactin mRNA, and Hypothalamic Vasoactive Intestinal Peptide mRNA Expressions in Yangzhou Ganders

## TL;DR

Immunizing geese against inhibin affected sperm production and hormone levels, but did not improve reproductive efficiency as expected.

## Contribution

This study evaluates the effects of inhibin immunization on reproductive hormones and testicular function in Yangzhou ganders.

## Key findings

- INH immunization impaired spermatogenesis and seminiferous epithelium in geese.
- Plasma LH concentrations were lower in INH-immunized ganders compared to controls.
- Hypothalamic VIP mRNA and pituitary PRL mRNA expressions were higher in the control group.

## Abstract

Reproductive efficiency in the goose is an innovative approach critical for the thriving global industry. A poor reproductive performance and seasonality in reproduction are two of the most significant challenges in optimizing reproductive efficiency in the goose industry. Therefore, maximum profits from the goose breeder stock cannot be gained without achieving higher fertility and hatchability. Inhibin (INH) is a key hormone secreted by Sertoli cells in the testes, mainly involved in the regulation of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) production. Furthermore, INH immunization has elevated reproduction outcomes in some mammalian and commercial avian species. Our results demonstrate that INH immunization significantly affected spermatogenesis and seminiferous epithelium. LH concentrations (ng/mL) were observed to be lower in the INH-immunized group compared with the control group. Hypothalamic vasoactive intestinal peptide (VIP) mRNA and pituitary prolactin (PRL) mRNA expressions remained higher in the control group at 181 and 200 days of age in both, except on day 227. Overall, the data suggest that the INH immunization did not improve reproductive efficiency in Yangzhou ganders concerning plasma LH, testicular histology, pituitary PRL mRNA, and hypothalamic VIP mRNA expressions.

Inhibin (INH) plays a key role in the regulation of the reproductive performance of geese. It inhibits follicle-stimulating hormone (FSH) secretion from the anterior pituitary gland to regulate spermatogenesis. Immunization against INH in male geese leads to the production of antibodies to neutralize the INH activity that enhances testicular function and gonadotropin production. The objectives of the present research were to elaborate on the effects of inhibin (INH) immunization on testicular histology, plasma LH, pituitary PRL mRNA, and hypothalamic VIP mRNA expressions in Yangzhou ganders. A total of 60 birds were selected and divided into control (CON) and INH-immunized (INH-immunized) groups, having 30 in each group. In this experiment, the ganders were immunized with INH three times, and birds in the CON group were inoculated with bovine serum albumin (BSA). The analyzed data revealed that immunization against inhibin had no significant effects on improving the plasma concentration of LH hormone; however, significant effects were observed on the germ cell line, hypothalamic VIP mRNA, and pituitary PRL mRNA expressions. It is concluded that INH (INH) immunization is an effective tool to improve reproductive efficiency in Yangzhou ganders; however, INH immunization may harm pituitary PRL mRNA and hypothalamic mRNA expressions and LH plasma concentration. Seasonality played a vital impact on the hypothalamus–pituitary–gonadal (HPG) axis.