{
  "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.",
  "abstract_shown": true,
  "affiliations": [
    "Laboratory of Functional Anatomy, Department of Animal and Marine Biosciences, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, 819-0395, Japan.",
    "Laboratory of Functional Anatomy, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, 819-0395, Japan.",
    "Laboratory of Functional Anatomy, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, 819-0395, Japan. Electronic address: hosaka@agr.kyushu-u.ac.jp."
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Xiao Zhang"
    },
    {
      "affs": [
        0
      ],
      "name": "Kota Hoshina"
    },
    {
      "affs": [
        0
      ],
      "name": "Miyu Uemori"
    },
    {
      "affs": [
        1
      ],
      "name": "Shiro Egawa"
    },
    {
      "affs": [
        1
      ],
      "name": "Shotaro Nishimura"
    },
    {
      "affs": [
        2
      ],
      "name": "Yoshinao Z Hosaka"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bvytngy3pbx5p.bib",
  "cited_by": 0,
  "doi": "10.1016/j.psj.2026.107932",
  "fulltext_url": "https://europepmc.org/articles/PMC13681983",
  "id": "bvytngy3pbx5p",
  "issns": [
    "0032-5791",
    "1525-3171"
  ],
  "landing_url": "https://europepmc.org/article/MED/42863179",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1103|Meat and Animal Product Quality"
    ]
  ],
  "openalex": "W7221129393",
  "pdf_url": "https://europepmc.org/articles/PMC13681983?pdf=render",
  "pmcid": "PMC13681983",
  "pmid": "42863179",
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bvytngy3pbx5p.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:00Z",
      "native_id": "MED:42863179",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42863179"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1103|Meat and Animal Product Quality",
      "subfield": "zoology-behaviour"
    }
  ],
  "title": "Immunocastration and testosterone supplementation alter testicular development and muscle collagen gene expression in male chickens.",
  "title_text": "Immunocastration and testosterone supplementation alter testicular development and muscle collagen gene expression in male chickens.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:19:00Z",
  "url": "https://research.draconitic.com/paper/bvytngy3pbx5p",
  "venue": "Poultry science",
  "versions": []
}