Neonicotinoids Toxicity in Hypophthalmichthys nobilis (Richardson, 1845): Clinico-haematological and Erythrocytic Morphological Alterations

Neonicotinoids or chloronicotinyl insecticides (neonics) are a new group of insecticides that are frequently used for the protection of agricultural crops. The Nitenpyram (NTP), a commonly used neonicotinoid insecticide on a global scale, has been recognized as a non target aquatic organism contaminant. This research has been done to explore the toxic effects of NTP on the freshwater carp (Hypophthalmichthys nobilis). Following a week of acclimatization period, a total of 108 healthy fish with average body weight 48±0.07 g were divided into three groups, with each group being replicated twice (12 fish per replicate). C0 was untreated group (control), while group C1 and C2 were exposed to different concentrations of NTP, 0.02 and 0.04 mg/L respectively for 14 days. NTP-intoxicated fish manifested severe behavoral changes include convulsions, jerking, exhaustion, increased opercular movement, body curvature, breathing problems, mouth redness, fin erosion, and gasping. There were significant changes in the hematological indices because of NTP exposure, e.g. Mean Corpuscular Volume (MCV), Neutrophils (N), Lymphocytes (L), Monocytes (M), and Leukocytes (W) were highly elevated, while Red Blood Cells (RBC), Hemoglobin (HGB), and Hematocrit (HCT) were considerably reduced in experimental groups C1 and C2 as compared to control group C0 (P<0.05). The percentage of erythrocytic cellular changes comprising, microcytes, acanthocytes, pear shaped erythrocytes, leptocytes and fused erythrocytes, along with erythrocytic nuclear abnormalities influencing micronucleus, kidney shaped nuclei, eccentric nuclei, blabbed nuclei, and bilobed nuclei were recognized. These results indicated that exposure to NTP caused significant adverse effects on fish blood health, suggesting that the ecosystem and non-target aquatic life is at danger from this widely used pesticide.