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Reproduction, Fertility and Development Reproduction, Fertility and Development Society
Vertebrate reproductive science and technology
RESEARCH ARTICLE

The impact of GnRH immunocastration on colonic microbiota and metabolites in male sheep

Shehr Bano Mustafa A # , Hua Long B # , Tianzeng Song C D , Xiaoming Zhang A , Yangzong Zhaxi C , Jing Wu A , Xiaoying Chen C , Khuram Shahzad E , Xunping Jiang D , Guiqiong Liu D , Xianyin Zeng F * and Wangsheng Zhao https://orcid.org/0000-0002-6339-329X A *
+ Author Affiliations
- Author Affiliations

A College of Life Sciences and Agri-forestry, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China.

B Shigatse High-tech Industrial Development Center, Shigatse, Xizang 857000, China.

C Institute of Animal Science, Xizang Academy of Agricultural and Animal Husbandry Science, Lhasa, Xizang 850009, China.

D College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070, China.

E Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad (CUI), Lahore Campus, Defence Road, Off Raiwind Road, Lahore, 54000, Pakistan.

F College of Life Science, Sichuan Agricultural University, Ya’an 625000, China.


# These authors contributed equally to this paper

Handling Editor: Graeme Martin

Reproduction, Fertility and Development 37, RD24191 https://doi.org/10.1071/RD24191
Submitted: 5 December 2024  Accepted: 13 May 2025  Published online: 5 June 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing

Abstract

Context

Castration of lambs is an old practice for managing reproduction and improving meat quality. However, the traditional method raises welfare concerns. To overcome these limitations, immunocastration has gained attention as an ethical and effective solution to the welfare challenges associated with surgical castration by targeting the hypothalamic-pituitary-gonadal axis.

Aims

In this investigation, we study the impact of gonadotrophin-releasing hormone (GnRH) immunocastration by analysing its influence on testosterone levels, colon microorganisms, and metabolomics.

Methods

The experiment is divided into immunocastrated (IMCF), surgically castrated (ORCCF), and control (EMCF) groups of male sheep. Blood and fecal samples were collected for testosterone measurement, metabolomics and microbiota analysis. Metabolomics was analysed by LC-MS/MS, while microbiota analysis was performed using 16S rRNA sequencing.

Key results

The testosterone level in both IMCF and ORCCF groups significantly declined compared to the EMCF. Furthermore, the relative abundance of bacteroidota to Firmicutes was higher in the IMCF and ORCCF groups compared to the EMCF group. The IMCF group showed increased levels of beneficial genera, Bacteroides, compared to the ORCCF and EMCF groups. Furthermore, metabolomics analysis revealed that GnRH immunocastration significantly affected some metabolites, such as methyl stearate and 23-nordeoxycholic acid, which were significantly upregulated in the IMCF group relative to the ORCCF group. In contrast, N′-formylkynurenine and 6-aminonicotinamide showed marked downregulation.

Conclusions

GnRH immunocastration is an effective alternative to surgical castration with added benefits for health and metabolic efficiency, highlighting its potential advantages in animal welfare and productivity.

Implications

The study highlights the potential of GnRH immunocastration, which contributes to advancing modern techniques. This approach offers ethical livestock management practices.

Keywords: colonic, GnRH immunocastration, metabolomic, microbiome, sheep, surgical castration, testosterone, 16S rRNA sequencing.

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