Toxicological effects and recovery of the corneal epithelium in Cyprinus carpio communis Linn. exposed to monocrotophos: an scanning electron microscope study.

This study was conducted based on the evidence of fish habitats in North India being affected by organophosphate pesticides draining from agricultural fields into bodies of water, especially during the rainy season. Various tissues of fish such as scales, gills ovaries, kidney, and liver have been studied from the toxicological point of view, but the toxicological effects of aquatic pollutants on fish cornea have not been investigated to date. We conducted comparative toxicological studies on the cornea of Cyprinus carpio communis using two sublethal (0.038 and 0.126 ppm) concentrations of monocrotophos pesticide for 30 days. Corneas from all the groups were evaluated by a scanning electron microscope. The fish exposed to the monocrotophos pesticide developed corneal necrosis due to the formation of crystalloid-like structures, thinning and shrinkage of microridges on the corneal epithelium. After 30 days, fish from the monocrotophos-treated tank were transferred to normal environmental conditions. After 60 days under natural condition, epithelial cells did not fully recover. In conclusion, exposure to monocrotophos induces irreversible changes in the cornea of C. carpio communis. As fish and mammalian visual systems share many similarities, the reported finding may offer useful insights for further toxicological and ophthalmological studies in humans.

Sources and Levels of Trace Elements Influence Some Blood Parameters in Murrah Buffalo (Bubalus bubalis) Calves.

Sources of supplemental minerals in the diet of animals are of important significance. Bio-availability of organic sources is believed to be more in the body as compared to regularly used inorganic sources and hence environment-friendly due to reduced mineral excretion, which in turn reduces their requirements in the diet as well. Twenty-four male Murrah buffalo (Bubalus bubalis) calves (about 18-20 months of age and 318.54 ± 8.85 kg body weight) were divided randomly into four groups of six animals each. In the control group (C, InOrg100) zinc (Zn), copper (Cu), and manganese (Mn) were supplemented through an inorganic source, while in treatment groups, organic source at the rate of 50, 75, or 100% (in groups T1 (Org50), T2 (Org75), and T3 (Org100), respectively) was fed at level as supplemented in the control group. Feeding was continued for a period of 180 days with blood sampling at day 0 followed by a regular interval of 45 days. Plasma samples were analyzed for trace elements Cu, Mn, Zn, and iron (Fe), total antioxidant status, ceruloplasmin, and superoxide dismutase (SOD) with cell-mediated and humoral immune response. Plasma levels of different trace minerals like Fe, Mn, and Cu remained unaffected with two sources and different levels of organic minerals, except the level of Zn, which showed higher (P < 0.05) levels in the group Org100 compared to others, and remained indicative of higher bio-availability through the organic source. The concentration of plasma total antioxidants indicated no adverse effect on the reduction of supplemental levels up to half of these minerals. Also, the level of plasma SOD was high (P < 0.05) at each level of the organic source as compared to the 100% level of the inorganic source. Immune response in respect of cell-mediated as well as humoral immunity did not show any reduction in different groups. The study indicated beneficial impacts of the organic source in the form of superior plasma Zn level as well as SOD concentrations. In addition, no negative effect on most of the studied parameters was observed after reducing supplemental trace minerals to half indicating higher bio-availability of organic trace minerals.