Non-lethal sampling of liver tissue for toxicologic evaluation of Florida cottonmouths snakes, Agkistrodon piscivorus conanti

Abstract

Due to their longevity, strong site tenure, poikilothermic metabolism, and low-energy specializations, reptiles might serve as excellent environmental sentinels. Cottonmouth snakes are generalist predators and scavengers, and as such, may have higher exposure to persistent environmental contaminants as a result of bioaccumulation. Traditionally, assessment and monitoring of contaminant exposure in reptiles have involved lethal sampling techniques. In this paper, we describe a non-destructive technique for sampling liver tissue in live anesthetized Florida cottonmouths. Wild-caught snakes (n = 21) were anesthetized with propofol, and a liver wedge biopsy was obtained by clamping the edge of the organ with two small hemostatic mosquito forceps via right-sided coeliotomy incision. A minimum required tissue sample weighing >100 mg was harvested from all except one of the animals. No mortalities occurred during the procedures or recovery from anesthesia, and all snakes were released back into the field after the animal had consumed prey and defecated, usually within 2 weeks following surgery. Hemorrhage was a minor complication in most snakes, especially those with friable discolored livers. The procedure appeared to have no short-term deleterious effects, and two biopsied individuals were captured after being released into the field and appeared to be normal and healthy. However, follow-up studies and recapture of more snakes are needed to assess long-term survivability. Our non-destructive liver sampling technique might be implemented in toxicological studies of other squamates and could help to minimize the lethal sampling of threatened species.

Serpientes: un campo no explorado

“…Su longevidad, su poca vagilidad, su metabolismo poiquilotermo y sus hábitos alimenticios principalmente carnívoros, les proporcionan una alta capacidad para bioacumular y biomagnificar este tipo de xenobioticos, de tal forma que la exposición a estos contaminantes puede llegar a ser sumamente prolongada y causar estragos en los diferentes niveles tróficos en que participan estos animales. (Hopkins, 2000;Quesada et al, 2014).…”

“…Actualmente, varios de los trabajos de ecotoxicología realizados con serpientes, han implementado el uso de biomarcadores no letales, tales como los pedazos de cola o "tail clips", sangre, y más recientemente las mudas de piel (Tabla 4). Algunas investigaciones incluso se han centrado únicamente en corroborar la utilidad de dichos biomarcadores, y otras, como es el caso de lo reportado por Quesada et al, 2014, proponen biopsias no letales de hígado para el análisis de contaminantes bioacumulados en serpientes.…”