Cytochrome P450 induction, hematological changes and melanomacrophage accumulation in Nile tilapia (Oreochromis niloticus Linn.) after exposure to chlorpyrifos

Issue Date

10-2003

Abstract

This study aimed to evaluate some pesticide-induced physiological responses in Nile tilapia (Oreochromis niloticus Linn.), which may be developed as biomonitoring indices for organophosphate exposure. Male juvenile fishes were grouped (15 individuals per group) and exposed daily for 20 days to varying concentrations of chlorpyrifos, namely: 0.3 µg/L, 1.0 µg/L, 1.7 µg/L. The different residual doses were administered through daily incorporation of the desired concentrations of the test materials in aquarium water. The control fishes were maintained in the untreated water. The specimens were examined after one, three and ten days following the treatments. Analysis revealed significant induction in cytochrome P450 levels among the treated fishes (P<0.05) even at ten days following the treatment period. The mean corpuscular volume and the mean corpuscular hemoglobin levels also appeared to have been influenced by the treatment. Moreover, a significant increase in heterophils and a decrease in lymphocytes were noted in fishes under 1.6 µg/L treatment level. Histological analysis of the liver tissues showed an apparent proliferation of melanomacrophage centers among fishes exposed to 1.6 µg/L concentration. Induction of cytochrome P450 levels denotes detoxifying activity due to the presence of a toxicant, which could cause considerable stress on animals as evidenced by the hematological changes and increase in size of the melanomacrophage centers.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

17

Issue

1

Page

66-76

Document Type

Article

Frequency

semi-annually

Physical Description

illustration; graphs

Language

English

En – AGROVOC descriptors

OREOCHROMIS NILOTICUS; CYTOCHROME P450; CHLORPYRIFOS; HEPATOPANCREAS; PESTICIDES; AQUATIC ECOSYSTEMS

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