The Lethal impacts of roundup® (glyphosate) on the fingerings of guppy, Poecilia reticulate peters, 1859
2011
Chandrasekera, W. U. | Weeratunga, N. P.
Weedicides bring about adverse effects to non-targeted animal species in the agricultural fields and associated habitats. Among these, Roundup® (glyphosate) is one of the commonest that is used all over the world. The present laboratory investigation examined the effects of Roundup® on fingerlings of guppies (Poecilia reticulata). In this investigation, the 24-hr and 96-hr LC₅ₒ of Roundup® for the guppy fingerlings were determined by exposing them to a series of Roundup® test preparations ranging from 3.6 mg.L¯¹ to 36 mg.L¯¹. Further, the behavioural changes of thefingerlings at these test preparations were studied and the histopathological changes of their gills were examined. Theresults showed that the 24-hr and 96-hr LC₅ₒ for Roundup® were 15.1 mg.L¯¹ and 9.76 mg.L¯¹ respectively. These values are well below the recommended field concentration of Roundup®, which is 2,592 mg.L¯¹. Fingerlings preferred to rest more at the surface of test preparations than resting elsewhere in the tanks. In contrast, such a behavioural change was not observed in the control. The histopathological study showed that the fingerlings exposed to all the Roundup® concentrations developed gill hyperplasia where its severity was concentration dependent. It is evident that the toxic concentration of Roundup® on guppy fingerlings is much lower than its recommended field concentration. At these toxic concentrations, Roundup® brings about stress and severe gill damage in guppies.
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