_1776567873 20260419030433000 Rovedar Daryoushbabazadeh@gmail.com Rovedar Journal of Lab Animal Research J Lab Anim. Res 2980-9703 02 11 2026 5 1 Natalie Steiner https://orcid.org/0000-0002-5057-1173 Tina Brezzina https://orcid.org/0009-0001-4177-8025 Felix Felmy https://orcid.org/0000-0002-0957-4241 Frederik Kiene https://orcid.org/0000-0003-2517-8553 Yara Silberstein https://orcid.org/0009-0006-3694-0557 Malgorzata Ciurkiewicz https://orcid.org/0000-0001-6277-7366 Andreas Beineke https://orcid.org/0000-0003-2187-3436 Jan Hinrich Bräsen https://orcid.org/0000-0002-2863-3067 Reinhold Paul Linke https://orcid.org/0009-0001-1067-5242 Claudia Busse https://orcid.org/0009-0008-4070-7891 Michael Pees https://orcid.org/0000-0002-7244-9697 Ute Radspiel https://orcid.org/0000-0002-0814-2404 Maximilian Reuschel https://orcid.org/0000-0001-8083-677X Introduction: Captive tree shrews (Tupaia belangeri) are widely used as experimental models for neurological, visual, and infectious disease studies. Despite evidence suggesting a genetic or physiological predisposition to systemic amyloidosis in this species, its clinicopathological characteristics are still poorly understood. The present study aimed to characterize clinicopathological changes associated with systemic amyloidosis in a captive breeding colony of Tupaia belangeri (T. belangeri) and to explore potential early ante-mortem indicators in blood indices, imaging, or clinical examination of the disease.Materials and methods: Nineteen T. belangeri were included in the present study (seven males, 12 females) with a mean age of 3.3 years from a single institutional breeding colony at the University of Veterinary Medicine Hannover, Germany. Fifteen animals underwent standardized ante-mortem clinical assessment, including physical and ophthalmic examination, serum biochemistry, urinalysis, radiography, and abdominal ultrasonography, followed by necropsy and histopathology. Four animals were included solely on the basis of pathological and histological examination due to long intervals between the prior clinical evaluation and necropsy. Amyloid was identified histologically by Congo red staining and confirmed as AA-type by immunohistochemistry.Results: Systemic AA-amyloidosis was detected in 74% of the examined T. belangeri (14/19), predominantly affecting the kidneys and intestines. A significant association was observed between renal cysts and amyloid deposition. An association with urine specific gravity was observed, while no significant associations were identified between amyloidosis and other biochemical, urinary, radiographic, or ultrasonographic parameters, nor with sex, body weight, or age.Conclusion: Systemic AA-amyloidosis appeared to be common in captive T. belangeri, predominantly affecting the kidneys and intestine, while lacking reliable ante-mortem clinical or laboratory indicators, highlighting the need for improved diagnostic approaches. 02 14 2026 1 14 https://creativecommons.org/licenses/by/4.0 10.58803/jlar.v5i1.88 https://jlar.rovedar.com/index.php/JLAR/article/view/88 https://jlar.rovedar.com/index.php/JLAR/article/download/88/128 https://jlar.rovedar.com/index.php/JLAR/article/download/88/128 10.1111/ejn.16651 10.1016/j.theriogenology.2007.09.030 10.1093/emph/eow014 German center for the protection of laboratory animals (Bf3R). Use of laboratory animals in 2023. German Federal Institute for Risk Assessment (BfR). 2025. 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