Immunocastration and testosterone supplementation alter testicular development and muscle collagen gene expression in male chickens.
- 1Laboratory of Functional Anatomy, Department of Animal and Marine Biosciences, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, 819-0395, Japan.
- 2Laboratory of Functional Anatomy, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, 819-0395, Japan.
- 3Laboratory of Functional Anatomy, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, 819-0395, Japan. Electronic address: [email protected].
Abstract
Immunocastration using a gonadotropin-releasing hormone (GnRH) vaccine offers a potential alternative to surgical castration in poultry, yet its effects on growth performance and meat quality in chickens remain poorly characterized. Thirty-six male Sakura chickens were allocated to three groups (n = 12): control (C), immunocastration with Improvac at 4 and 8 wk (I), and immunocastration plus subcutaneous testosterone implantation at 8 wk (T). Birds were sampled at 10 and 16 wk. Immunocastration induced anti-GnRH antibody production in both I and T groups compared with C (P < 0.001 and P < 0.01, respectively). At 16 wk, serum testosterone was lower in I than in C (P < 0.05), whereas T showed levels comparable to C. Gonadosomatic index was markedly reduced in T at 16 wk compared with both C and I (P < 0.001 and P < 0.01, respectively), possibly reflecting combined HPG axis suppression by immunization and negative feedback by exogenous testosterone. Body weight was higher in C than in I and T from 7 wk onward (P < 0.01), but overall average daily gain did not differ among groups. Muscle color (L*, a*) differed between groups in the thigh but not in the breast. Raw shear force of the iliotibialis lateralis (ITL) was lower in I than in C and T (P < 0.05 and P < 0.001, respectively), suggesting that immunocastration may reduce connective tissue stiffness in thigh muscle. In the breast muscle, COL3A1 mRNA expression was elevated in T compared with C and I (P < 0.001 and P < 0.01, respectively), suggesting that testosterone may influence collagen gene expression in a muscle-specific manner. Further optimization of vaccination protocols specific to chickens is warranted to improve the consistency and efficacy of immunocastration effects.
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BibTeX
@article{zhang2026immunocastration,
title = {{Immunocastration and testosterone supplementation alter testicular development and muscle collagen gene expression in male chickens.}},
author = {Xiao Zhang and Kota Hoshina and Miyu Uemori and Shiro Egawa and Shotaro Nishimura and Yoshinao Z Hosaka},
journal = {Poultry science},
year = {2026},
month = oct,
doi = {10.1016/j.psj.2026.107932},
url = {https://europepmc.org/article/MED/42863179},
note = {CC BY},
}
RIS
TY - JOUR
TI - Immunocastration and testosterone supplementation alter testicular development and muscle collagen gene expression in male chickens.
AU - Xiao Zhang
AU - Kota Hoshina
AU - Miyu Uemori
AU - Shiro Egawa
AU - Shotaro Nishimura
AU - Yoshinao Z Hosaka
PY - 2026
DA - 2026/10/09
JO - Poultry science
DO - 10.1016/j.psj.2026.107932
UR - https://europepmc.org/article/MED/42863179
AB - Immunocastration using a gonadotropin-releasing hormone (GnRH) vaccine offers a potential alternative to surgical castration in poultry, yet its effects on growth performance and meat quality in chickens remain poorly characterized. Thirty-six male Sakura chickens were allocated to three groups (n = 12): control (C), immunocastration with Improvac at 4 and 8 wk (I), and immunocastration plus subcutaneous testosterone implantation at 8 wk (T). Birds were sampled at 10 and 16 wk. Immunocastration induced anti-GnRH antibody production in both I and T groups compared with C (P < 0.001 and P < 0.01, respectively). At 16 wk, serum testosterone was lower in I than in C (P < 0.05), whereas T showed levels comparable to C. Gonadosomatic index was markedly reduced in T at 16 wk compared with both C and I (P < 0.001 and P < 0.01, respectively), possibly reflecting combined HPG axis suppression by immunization and negative feedback by exogenous testosterone. Body weight was higher in C than in I and T from 7 wk onward (P < 0.01), but overall average daily gain did not differ among groups. Muscle color (L*, a*) differed between groups in the thigh but not in the breast. Raw shear force of the iliotibialis lateralis (ITL) was lower in I than in C and T (P < 0.05 and P < 0.001, respectively), suggesting that immunocastration may reduce connective tissue stiffness in thigh muscle. In the breast muscle, COL3A1 mRNA expression was elevated in T compared with C and I (P < 0.001 and P < 0.01, respectively), suggesting that testosterone may influence collagen gene expression in a muscle-specific manner. Further optimization of vaccination protocols specific to chickens is warranted to improve the consistency and efficacy of immunocastration effects.
SN - 0032-5791
SN - 1525-3171
ER -