A preliminary study of immunological castration in colts.
Abstract: This study tested the effectiveness of a conjugated GnRH vaccine for stimulating antibody production, suppressing testosterone secretion and depressing testicular development in yearling colts. Two colts were allocated to each of three groups, (1) control, (2) subcutaneous and (3) intramuscular vaccinations. Two injections of the vaccine were given 11 weeks apart. Liveweight gain was not affected by vaccination but plasma testosterone concentrations in the treated colts were suppressed and their antibody titres to GnRH were greater than 1:1000. Testicular development in the treated colts also was retarded at this time, which was approximately 28 weeks after the first injection. Semen samples, containing spermatozoa, were collected from all the colts prior to their castration at the end of the investigation. Antibody titres and testosterone concentrations in the treated colts had returned to levels similar to those of the controls by the end of the experiment. The testes of the vaccinated colts were still smaller than those of the controls on castration but were, nevertheless, increasing in size. Morphometric analysis of testicular histology and daily sperm production data indicated that the testes of the treated colts were recovering and would probably have regained normal function had they been left in situ.
Publication Date: 1991-01-01 PubMed ID: 1795260
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study explores the impact of a specific vaccine on the suppression of testosterone and inhibition of testicular development in young male horses. Though the effects were temporary, the results suggest potential for using this method as a form of immunological castration.
Overview of the Experiment
- The experiment involved testing a conjugated GnRH (Gonadotropin-releasing hormone) vaccine on yearling colts to study whether it could stimulate antibody production, suppress testosterone secretion, and hinder testicular development.
- The colts were divided into three groups – control, subcutaneous vaccination, and intramuscular vaccination. The vaccine was administered in two doses, with an interval of 11 weeks between each dose.
Results of the Experiment
- The vaccine did not affect the gain in liveweight of the treated colts. Nonetheless, it successfully reduced the plasma testosterone concentrations and increased antibody titres to GnRH, implying a successful immune response.
- There was retardation in the testicular development of the treated colts approximately 28 weeks post the initial injection.
- Despite the vaccination, all the colts were able to produce spermatozoa prior to castration, which was conducted at the end of the study.
Post-Experiment Observations
- By the end of the experiment, both the antibody titres and testosterone concentrations in the vaccinated colts had returned to levels similar to those of the control group.
- Although the testes of the vaccinated colts were smaller compared to those of the control group, they were observed to be increasing in size.
- A close analysis of the testicular histology and daily sperm production data suggested that the testes of the treated colts were heading towards recovery and would probably have regained normal function if left intact.
Conclusion
- This study provides preliminary evidence suggesting potential for the conjugated GnRH vaccine as a form of immunological castration in colts. The effects, however, are temporary, with functions expected to return to normal over time.
- The study highlights the need for additional research to confirm these findings, understand the implications of these vaccinations in the long term and to determine whether these results can be replicated in other species.
Cite This Article
APA
Dowsett KF, Pattie WA, Knott LM, Jackson AE, Hoskinson RM, Rigby RP, Moss BA.
(1991).
A preliminary study of immunological castration in colts.
J Reprod Fertil Suppl, 44, 183-190.
Publication
Researcher Affiliations
- Department of Farm Animal Medicine and Production, University of Queensland, St. Lucia, Australia.
MeSH Terms
- Animals
- Antibody Formation
- Gonadotropin-Releasing Hormone / immunology
- Horses / immunology
- Male
- Testis / anatomy & histology
- Testosterone / blood
- Time Factors
- Vaccines, Synthetic / immunology
- Weight Gain
Citations
This article has been cited 4 times.- Botha AE, Schulman ML, Birrell J, du Plessis L, Laver PN, Soley J, Colenbrander B, Bertschinger HJ. Effects of an anti-gonadoliberin releasing hormone vaccine on testicular, epididymal and spermatogenic development in the horse.. Reprod Domest Anim 2022 Aug;57(8):919-927.
- Ganaie JA, Gautam V, Shrivastava VK. Effects of Kamdhenu Ark and Active Immunization by Gonadotropin Releasing Hormone Conjugate (GnRH-BSA) on Gonadosomatic Indices (GSI) and Sperm Parameters in Male Mus musculus.. J Reprod Infertil 2011 Jan;12(1):3-7.
- Meeusen EN, Walker J, Peters A, Pastoret PP, Jungersen G. Current status of veterinary vaccines.. Clin Microbiol Rev 2007 Jul;20(3):489-510, table of contents.
- Jana K, Samanta PK, Ghosh D. Dose-dependent response to an intratesticular injection of calcium chloride for induction of chemosterilization in adult albino rats.. Vet Res Commun 2002 Dec;26(8):651-73.
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