A comparative study on the effects of selected pesticides on hemato-biochemistry and tissue histology of freshwater fish Cirrhinus mrigala (Hamilton, 1822)

Abstract

The aim of the present study was to investigate the comparative effects of pesticides Chlorfenapyr, Dimethoate and Acetamiprid on the health of Cirrhinus mrigala under long term exposure. Eighty C. mrigala were divided in four equal groups; one control and three treated groups. The blood was collected from both control and treated groups at intervals of 10th, 20th and 30th days for hemato-biochemistry and histopathological alterations. The result indicates significant difference (P < 0.05) in RBCs, Hb, PCV and MCHC whereas elevation in WBCs and Platelets counts were recorded. In 10th day sampling, MCV value of Dimethoate and Acetamiprid treatment had no difference in comparison with the control group, however it is significantly increased (P < 0.05) in rest of sampling. The MCH value of exposed fish showed significant increased (P < 0.05) after 20th and 30th days for Chlorfenapyr and after 30th days for Acetamiprid exposure while insignificantly increased for rest of sampling. It was also found that these pesticides significantly decrease (p < 0.05) the T3 and T4 levels while increase in the TSH, cortical, ALP, AST, ALT and LDH levels in the serum of the treated fishes in contrast to control group. Similarly, histopathological analysis of gills and liver showed significant alterations in all the treated groups. Toxicity trends of these pesticides was ranked as Chlorfenapyr > Acetamiprid > Dimethoate. It is concluded that indiscriminate use of such pesticides poses a noxious threat to non-target organisms, harm the ecosystems and jeopardizes human health.

Keywords: Acetamiprid; C. mrigala; Chlorfenapyr; Dimethoate; Histopathology and hematology.

Fig 1

RBC, WBC, Hb, Hct, MCV, MCH, MCHC and platelets of C. mrigala after Chlorfenapyr, Dimethoate and Acetamiprid exposure. Values are expressed as mean ± SE from triplicate groups. Bars with * indicate significant differences while Bars with ** indicate highly significant differences between control and treated groups.

Fig 2

Serum T3, T4, TSH, ALP, AST, ALT and LDH cortisol levels of C. mrigala after Chlorfenapyr, Dimethoate and Acetamiprid exposure. Values are expressed as mean ± SE from triplicate groups. Bars with * indicate significant differences while Bars with ** indicate highly significant differences between control and treated groups.

Fig 3

Light micrographs of H & E stained sections of liver of Cirrhinus mrigala: (L1) Control group liver showing normal structure, (L2 to L6) treated groups liver showing various histopathological alterations including blood congestion (BC), lymphocytes infiltration (LI), pyknotic nuclei (PK), aggregation of melanomacrophage (Mm), necrosis (N), foamy cells (FC), blood sinusoid dilation (BS), vaculation (V) and hypertrophy (H).

Fig 4

Light micrographs of H & E stained sections of Gills of Cirrhinus mrigala: (G1) Control group gills showing normal structure, (G2 to G6) treated groups gills showing various histopathological alterations including fusion of secondary gill lamellae (F), epithelial uplifting of secondary gill lamellae (E) hyperplasia of gill epithelium (H), curling of secondary gill lamellae (C), telangiectasia (T), shortening of secondary gill lamellae (S), disruption of cartilaginous core (DC), lamellar disorganization (LD) and lamellar atrophy (A).