Hepatic fibrosis induced zinc-deficient dermatosis in American alligators (Alligator mississippiensis) [article]

Ilaria M. Piras, Annemarie Bezuidenhout, Josué Díaz-Delgado, Deirdre Slawski, Pamela A. Kelly
2022 bioRxiv   pre-print
AbstractCrocodilian farming generates strong economic incentives for the conservation of several species previously endangered by intensive hunting. Ranching farms, in particular, are intimately connected to the natural crocodilian habitat and have a significant impact on wetland preservation. The financial sustainability of this industry relies on the production of first grade skins for the luxury leather market. Only flawless skins are considered of first grade by the stringent standards of
more » ... e market, and even a single defect represents an economical loss. "Double scale" (DS) is one such defect that drastically reduces the appeal and value of crocodilian skin. Although DS defects represent a threat to the economical sustainability of the farming industry, there is no scientific literature available on this topic. This study, carried out in a ranching farm of American alligators (Alligator mississippiensis), represents the first investigation into the pathogenesis of DS. We conducted histopathological and immunohistochemical examinations and correlated vitamin A and E, and mineral concentration in liver and serum from a cohort of farmed alligators with and without DS. Our results indicate that double scale is a keratinization disorder associated with zinc deficiency. Furthermore, we found that portal hypertension due to liver fibrosis, underlies Zn deficiency in cases of DS. Lastly, we found that chronic vitamin A toxicity can cause liver fibrosis in crocodilians. Our results, for the first time, demonstrate a causal association between liver disease and skin quality in a crocodilian species. This study reveals the conserved role of zinc in the homeostasis of reptilian skin. Also, we show that, like mammals, reptiles may develop liver fibrosis following chronic vitamin A toxicity and through activation of hepatic stellate cells. Our results advance herpetological medicine and will translate into improved captive crocodilian welfare and husbandry.
doi:10.1101/2022.08.30.505809 fatcat:qjbg37uc2bbq3m6vmlhyuhzzsm