Histopathological aspects of the liver of free-living and farmed bullfrogs (Lithobates catesbeianus)

José Teixeira De Seixas Filho,Oswaldo Pinto Ribeiro Filho,Marcio Hipolito,Marcelo Maia Pereira,Luara Lucena Cassiano,Sílvia Conceição Reis Pereira Mello,Ana Maria Cristina Rebello Pinto Da Fonseca Martins Martins,Claudio Barberini Camargo Filho

doi:10.1590/s1806-92902017000400001

Abstract

ABSTRACT The objective of this study was to compare the histopathological aspects of the liver of free-living and farmed bullfrogs (Lithobates catesbeianus). Thirty liver samples were collected from young and adult bullfrogs in the states of Minas Gerais and Rio de Janeiro, Brazil. Marked blood congestion and even hemorrhage and a large number of melanomacrophages were observed in most of the livers from free-living bullfrogs. Additionally, hepatocytes showed cytoplasmic eosinophilia and some showed nuclear hypertrophy and presence of microvesicular steatosis; [...]

Highlights

The bullfrog (Lithobates catesbeianus) was introduced in Brazil in the 1930s as a farming alternative because of its easy adaptation to the climate conditions of Brazil
Unlike the livers of animals reared on farms, the livers of free-living animals did not show any evidence of protein-mineral deficiency, characterized by cytoplasmic vacuolation and a larger number of melanomacrophages, suggesting greater aggression to the liver parenchyma, probably due to environmental toxicity
Histological analysis of the livers of bullfrogs showed the presence of many melanomacrophages, hepatocytes with eosinophilic cytoplasm, and some with highly enlarged nuclei intermingled with normal hepatocytes with clearer cytoplasm and round, typical nuclei (Figure 1)

Summary

Introduction

The bullfrog (Lithobates catesbeianus) was introduced in Brazil in the 1930s as a farming alternative because of its easy adaptation to the climate conditions of Brazil. Despite government requirements for the construction of barriers to prevent the escape of bullfrogs, some of these animals escaped and currently live free in the wild in several Brazilian states (Ferreira and Lima, 2012) and in other South American countries (Akmentis and Cardozo, 2010). The diet of free-living bullfrogs is based on invertebrates and small vertebrates (Hirai, 2004; Silva et al, 2009; Leivas et al, 2012). Those that provide the best performance have a crude protein content higher than 40% (Casali et al, 2005; Fenerick Jr. and Stéfani, 2005). The use of these commercial diets has caused some alterations in organs like the liver, which may compromise the animal performance (Seixas Filho et al, 2009; Seixas Filho et al, 2013)

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