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This study aimed to analyze the histomorphometry and ultrastructure of donkey skin and compare collagen fiber zones in various anatomical regions, both objectively and quantitatively. The study was the first to describe the melanosome number in different skin regions of a donkey. Skin biopsies from fourteen mature male donkeys were used in this study. The epidermis and dermis were examined histologically and ultrastructurally, focusing on the dermo-epidermal thickness ratio and collagen bundle arrangement in the dermis. The study revealed that melanin deposits are higher in the limbs and abdomen of donkeys compared to the back, neck, and thorax, and the dermal-epidermal junction of the back skin is longer. The back skin is the thickest, while the limb skin is the thinnest, despite the high collagen content in the thoracic region. The study indicates that the variation in melanin deposits and dermal-epidermal junction lengths in different body regions of donkeys may be due to variations in mechanical stress and environmental factors. The abdomen had the highest melanocyte count, with significant differences compared to the neck, back, and thorax. The neck region had the lowest count, while the limb, back, and thorax had similar counts. The study\u2019s findings could aid in identifying the difference between normal skin features and collagen-diseased skin in donkeys, aiding in diagnosis and providing valuable insights for veterinarians and researchers studying similar conditions.<\/jats:p>","DOI":"10.1186\/s12917-025-04712-0","type":"journal-article","created":{"date-parts":[[2025,5,2]],"date-time":"2025-05-02T11:04:50Z","timestamp":1746183890000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Elucidation of collagen content in different anatomical regions of the dermis of donkeys (Equus asinus): histomorphometric and ultrastructural study"],"prefix":"10.1186","volume":"21","author":[{"given":"Yasmeen","family":"Magdy","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ahmed","family":"Abo-Ahmed","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamed","family":"Abumandour","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anwar El","family":"Shafey","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Reda","family":"El-Kammar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mai A.","family":"AL-Mosaibih","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eman","family":"Fayad","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Osama","family":"Ahmed","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,5,2]]},"reference":[{"issue":"3","key":"4712_CR1","first-page":"1","volume":"33","author":"KA Al-Salihi","year":"2014","unstructured":"Al-Salihi KA, Farhat SF. 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Published by the Editorial Committee Hanover (Germany), Ghent (Belgium), Sapporo (Japan), Columbia, MO (U.S.A.), Rio de Janeiro (Brazil). 2017."}],"container-title":["BMC Veterinary Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12917-025-04712-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1186\/s12917-025-04712-0\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12917-025-04712-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,5,2]],"date-time":"2025-05-02T11:05:13Z","timestamp":1746183913000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmcvetres.biomedcentral.com\/articles\/10.1186\/s12917-025-04712-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,2]]},"references-count":54,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["4712"],"URL":"https:\/\/doi.org\/10.1186\/s12917-025-04712-0","relation":{},"ISSN":["1746-6148"],"issn-type":[{"value":"1746-6148","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,2]]},"assertion":[{"value":"17 March 2024","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"25 March 2025","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"2 May 2025","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"All methods were carried out in accordance with the Institutional Animal Care and Use Committee of Benha University and the National Institute of Health (NIH) guidelines in Egypt under the Animal Ethics number (Ethical No. BUFVTM 12-02-22), which accepted all procedures used in this study. The study was carried out in compliance with the ARRIVE guidelines. We confirmed that all owners had given their informed consent for the use of these donkeys in our study. Additionally, we obtained ethical approval from our institution\u2019s animal care committee prior to conducting any research involving the donkeys. This ensured that all necessary precautions were taken to prioritize the well-being of the animals throughout the study. All methods were performed in accordance with relevant guidelines and regulations from the Basel Declaration and the International Council for Laboratory Animal Science (ICLAS). The nomenclature used in this study was in accordance with Nomina Anatomica Veterinaria [].","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"All methods were carried out in accordance with the Institutional Animal Care and Use Committee of Benha University and the National Institute of Health (NIH) guidelines in Egypt under the Animal Ethics number (Ethical No. BUFVTM 12-02-22), which accepted all procedures used in this study.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Animal ethics declaration"}},{"value":"The authors declare no competing interests.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"310"}}