Pathological Effects of Benomyl in Male Japanese Quails (Coturnix japonica)

M Z Khan,I Javed,None Sajjad-Ul-Hassan,Q M Khan,G Muhammad,F Mahmood

doi:10.2754/avb200877020209

Abstract

The purpose of this experimental study was to observe the pathological and genotoxic effects of a systemic fungicide, Benomyl [methyl 1-(butyl carbamoyl)-2 benzimidazole carbamate] in male Japanese quails (Coturnix japonica). Benomyl (Benlate® DoPont 50% w/w benomyl) at dose rates of 0, 100, 400 and 1000 mg/kg for 8 consecutive days was administered into crops of quails kept in different groups. A significant decrease (p < 0.05) in feed intake, body weight and relative weight of testes was observed in benomyl-administered quails in a dose related manner. The size of testes decreased in benomyl treated quails. Microscopically, seminiferous tubules of testes exhibited a decreased number of spermatocytes, necrotic spermatids and syncytial cell formation. The number of quails developing testicular alterations increased in a dose-related pattern. These alterations reversed following a withdrawal of benomyl with the exception of the 1000 mg benomyl group, where these persisted till the end of the experiment (56th day). The mean tail length (μm) of the comets produced by leukocytes in single cell gel electrophoresis of 0, 100 and 400 mg dose level groups were 3.48, 3.24 and 3.29, respectively. The mean tail length of comets of the 1000 mg dose level group was 12.03 μm and significantly higher (p < 0.01) than in all other groups indicating DNA strand breaks at this dose level. These results suggested gonadotoxic effects of benomyl (Benlate®) and also a possible genotoxic effect at 1000 mg/kg level in Japanese quails.

Highlights

Benomyl [methyl 1-(butyl carbamoyl)-2 benzimidazole carbamate] is a systemic fungicide for a broad spectrum application at pre- and post-harvest stages of various food crops, fruits and vegetables
All the signs and behavioural alterations occurred in a dose-related manner, being most intense in group D, most subtle in group B and absent in controls
Dose levels of benomyl and the duration of exposure were decided arbitrarily as no toxicological data was available in avian species

Summary

Introduction

Benomyl [methyl 1-(butyl carbamoyl)-2 benzimidazole carbamate] is a systemic fungicide for a broad spectrum application at pre- and post-harvest stages of various food crops, fruits and vegetables. Benomyl and its primary metabolite, carbendazim, [methyl 2-benzimidazole carbamat], have been shown to be gonadotoxic and to induce a decrease in fertility, viability of sperm cells, decreased testes weight and testicular abnormalities in rats and dogs (Carter et al 1987; Barnes et al 1983; Linder et al 1988; Hess and Nakai 2000; Rajeswary et al 2007). Benomyl and carbendazim are known as aneuploidogens resulting in numerical chromosomal aberrations in vivo and in mammalian cells in vitro (Bentley et al 2000). There are conflicting reports of genotoxic effects of benomyl as tested by in vitro/in vivo techniques (Adhikari and Grover 1988). Many reports have described benomyl and carbendazim to give negative results in bacterial reverse gene mutation assays and/or bacterial DNA damage/repair tests (McCarroll et al 2002).

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