Effects of waterborne Diclofenac on guppy (Poecilia reticulata): behavioural, histopathological, developmental and haematological approach under chronic laboratory exposure

Abstract

Environmental presence of diclofenac, an anti-inflammatory drug, may pose threats to non-target organisms. Present study investigated the effects of chronic exposure of waterborne diclofenac on laboratory reared guppy (Poecilia reticulata) at two life history stages; juveniles (experiment I) and fries (experiment II). Both experiments consisted of one control group and three diclofenac exposed groups with concentrations of 1 μg/L, 10 μg/L, and 100 μg/L. Experiment I and II were conducted for 28 and 14 days respectively. Data were collected in the areas of behavioural endpoints (food detection time, physical avoidance response and ventilation rate), erythrocyte nuclear abnormalities (ENA) and gill histology in the experiment I, while it was done on predator avoidance response, osteology, and RNA/DNA ratio in the experiment II. For the behavioural endpoints there was no significant difference among groups (p>0.05) in juveniles. Diclofenac caused significant induction of ENA types except bi-nucleated cells and micronuclei compared to control group. Also, diclofenac exposed juveniles developed histopathological lesions in gills as inter-lamellar hyperplasia and dilated secondary lamellae. Fries exposed to diclofenac showed significantly lower (p<0.05) predator avoidance response than control group. Also, diclofenac caused alteration of the skeletal structure of guppy fries. There was no significant effect on the RNA/DNA ratio of fries. The present study revealed that 28-day exposure to waterborne diclofenac caused alterations in erythrocyte nuclear morphology and gill histology of juvenile guppy. The behavior was unaffected. Further, 14-day exposure of guppy fries to diclofenac caused alterations in predator avoidance behavior and osteology, but no significant effect on RNA/DNA ratio. Results collectively show that diclofenac in water is detrimental to developing guppy fries.