Gular Cutaneous Fibrosarcoma and Anatomophysiological Considerations for Anaesthesia in a Saddled Bichir, Polypterus endlicheri endlicheri

Karelma Frontera-Acevedo,Ayanna Carla N. Phillips Savage,Paola Roccabianca

doi:10.1155/2022/2199005

Karelma Frontera-Acevedo, Ayanna Carla N. Phillips Savage

Open Access

https://doi.org/10.1155/2022/2199005

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Abstract

Bichirs (Polypterus spp.) have frequently been studied with regard to comparative and developmental anatomy; however, very little information has been published regarding diseases, aging changes, and medical and surgical management in these species. Neoplasia represents one such example of conditions for which a dearth of information in these species exists. There has been increasing recognition of various types of neoplasms, including cutaneous tumors, particularly in ornamental fish; some of which may be related to environmental or to infectious causes. When excision of such tumors is indicated, surgical anaesthesia is required. However, special considerations may be warranted when employing immersion anaesthesia protocols in facultative air-breathing fish that can utilise the lungs for respiration. This anatomophysiological feature of Polypterus spp. may not only influence induction and maintenance of surgical anaesthesia but may theoretically have implications for drowning. Herein, we describe the management of a case of a rapidly growing gular neoplasm in a juvenile saddled bichir and considerations for surgical anaesthesia in this “lunged” species. Induction and maintenance of surgical anaesthesia using tricaine methanesulfonate (MS-222) in this species were found to be effective at significantly lower concentrations than standard recommended doses. Histopathological analysis identified the mass as a fibrosarcoma. To the best of our knowledge, this is the first report of a cutaneous fibrosarcoma in a bichir, representing the first report of neoplasia in Polypterus spp. and the first description of surgical anaesthesia in this amphibious fish.

Highlights

Bichirs (Polypterus spp.) are primitive ray-finned, freshwater fish of African origin [1]. They are among the few fish species that have lungs and can breathe air, and it is their evolutionary and developmental anatomy that has spawned great research interest [1, 2]
The surface epithelium lining the pulmonary lumen is composed of pneumocytes I, pneumocytes II containing lamellar bodies, mucous cells, and ciliated cells [6]
The animal was immersed in a bath containing tricaine methanesulfonate (Tricaine-S, MS-222) (Syndel Laboratories, Western Chemical and Aquatic Life Sciences, Ferndale, Washington USA) at a dose of 50 ppm buffered at a 1 : 2 ratio with sodium bicarbonate

Summary

Introduction

Bichirs (Polypterus spp.) are primitive ray-finned, freshwater fish of African origin [1]. They are among the few fish species that have lungs and can breathe air, and it is their evolutionary and developmental anatomy that has spawned great research interest [1, 2]. When the glottal valve opens, the body wall recoils and the subambient pressure aspirates air into the lungs [9]. This atypical respiratory anatomophysiological feature should be considered, in the surgical management of polypterid patients. We report on surgical anaesthetic considerations and the clinicopathological features of a cutaneous fibrosarcoma in the gular region of a saddled bichir (Polypterus endlicheri endlicheri) in Trinidad and Tobago

Case Description

Discussion

Conflicts of Interest