Morphological changes in the sperm storage tubules of the Japanese quail exposed to methy-2-benzimidazole carbamate

Abstract

The current investigation was an attempt to establish the effect of various doses of methyl-2-benzimidazole carbamate (carbendazim®) on the morphology of the Sperm Storage Tubules (SST) in the Japanese quail (Coturnix coturnix japonica). Carbendazim® in sunflower oil base was administered orally at doses of 0mg/kg (control), 25mg/kg, 100mg/kg, 400mg/kg and 800mg/kg body weight. Tissue samples from Uterovaginal junction were processed for both light (LM) and Transmission electron (TEM) microscopic study following standard procedures. The result showed that, at LM level, no histopathological changes were observed at a dose of 25mg/kg b.w.t. A significant decrease in SST width and luminal diameters was observed at doses of 100mg/kg and 400mg/kg b.w.t (p < 0.05). In addition, doses of 400mg/kg and 800mg/kg b.w.t caused leukocytic infiltration and hyperaemia in the lamina propria-submucosa. At these doses SST were devoid of spermatozoa. TEM results showed pyknosis, swollen mitochondria, vacuolation and increased number of lysosomes in degenerating SST. The observed morphological changes indicate the ability of carbendazim to disrupt structural integrity of SST as well as its storage capacity. This poses a great threat to the fertility of exposed birds and thus care must be taken to reduce environmental contamination.

Keywords: Carbendazim, histopathology, ultrastructure, Sperm storage tubules, Japanese quail