Effect of immunization against GnRH on hypothalamic and testicular function in rams

Area of Science:

• Veterinary Science
• Reproductive Biology
• Immunology

Background:

• Surgical castration is a common method for controlling ram reproductive function.
• Tibetan plateau conditions present unique challenges for livestock management.
• Alternative methods for reproductive control in Tibetan rams are needed.

Purpose of the Study:

• To evaluate the efficacy of active immunization against gonadotropin-releasing hormone (GnRH) in suppressing reproductive function in Tibetan rams.
• To compare the effects of GnRH immunization with surgical castration.

Main Methods:

• Thirty peripubertal Tibetan rams were divided into three groups: control, surgically castrated, or immunized against a GnRH-tandem-dimer peptide.
• Blood samples were collected for antibody titers and hormone analysis.
• Testicular histology and gene expression in the pituitary and testes were assessed.

Main Results:

• Active immunization against GnRH successfully induced a strong antibody response.
• GnRH immunization significantly reduced serum testosterone, inhibin A, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels.
• Immunization led to testicular atrophy, suppressed spermatogenesis, and decreased expression of key reproductive hormone receptors and subunits.

Conclusions:

• Active immunization against a GnRH-tandem-dimer-ovalbumin conjugate is an effective alternative to surgical castration in Tibetan rams.
• This approach offers a practical method for reproductive control in Tibetan plateau environments.
• The study demonstrates the potential of GnRH-based vaccines for livestock management.