The Effect of Diazinon on Blood Plasma Biochemistry in Carp (Cyprinus carpio L.)

Lusková V. , M. Svoboda, J . Koláfiová: The Effect of Diazinon on Blood Plasma Biochemistry in Carp (Cyprinus carpio L.). Acta Vet. Brno 2002, 71: 117-123. The aim of this study was to evaluate the effect of diazinon [0,0-diethyl-0-(2-isopropyl-6methylpyrimidin-4yl) phosphorothioate] on common carp (Cyprinus carpio L.). The effect was assessed by comparing the biochemical blood plasma profiles of a control group and a group exposed to the effect of the pesticide Basudin 600 EW (containing 600 g.l-1 diazinon as the toxic substance). The activities of selected enzymes, metabolite concentrations and electrolytes were measured in 15 specimens of controls, K1-2, and in 16 specimens, K1-2, exposed for 96 h to the effects of Basudin 600 EW at a concentration of 32.5 mg.l-1. Compared with the control group, a significant decrease of cholinesterase (p < 0.01) and lactate dehydrogenase (p < 0.05) was ascertained in the experimental group. The values of alanine and aspartate aminotransferases, creatine kinase, alkaline and acide phosphatases were comparable in the experimental and control groups. The total protein and lactate concentration were significantly lower (p < 0.05) in the experimental group, compared with the control group. On the contrary, glucose concentration in the plasma of the experimental group was significantly higher (p < 0.01) than in that of the control group. The experimental group showed a significantly higher (p < 0.05) concentration of plasmatic natrium and potassium, and a significantly lower (p < 0.05) concentration of plasmatic calcium and phosphorus, compared with those in the control group. The above results of examinations of the biochemical blood plasma profile indicate a marked neurotoxic effect of diazinon in fishes. Organophosphorous pesticide, acute toxicity, enzymes, total protein, glucose, lactate, electrolytes Diazinon is a widely used toxicant in a number of organophosphorous pesticides (Roberts and Hutson 1998). Although the aquatic environment is not the target one for the use of such pesticides the results of a number of monitoring studies have evidenced the presence of diazinon and its metabolite, diazoxon, in surface waters (Mansingh and Wilson 1996; Tsuda et al. 1996; Van der Geest et al. 1997; Bailey et al. 2000; de Vlaming et al. 2000). That is why great attention has been paid to the effect of diazinon on fish organism. Biochemical characteristics of blood are among the important indices of the status of internal environment of the fish organism (Edsall 1999). Changes in the biochemical blood profile mirror changes in metabolism and biochemical processes of the organism, resulting from the effects of various pollutants, and they make it possible to study the mechanisms of the effects of these substances. The major biochemical response to the effect of diazinon in fishes is the inhibition of a number of enzymes, above all acetylcholinesterase (Goodman et al. 1979; Sastry and Sharma 1980; Ansari et al. 1987; Hamm et al. 1998). Also observed have been changes in carbohydrate metabolism in the eel, Anguilla anguilla, during short-term exposure to diazinon (Ceron et al. 1997). The glycogen contents in the liver and muscular tissue was significantly decreased, glucose and lactate concentrations in the blood were significantly increased. Ansari and Kumar (1988) observed a significantly decreased content of DNA, RNA and liver proteins following a short-term action of diazinon on Zebra Danio, Brachydanio rerio. ACTA VET. BRNO 2002, 71: 117–123 Address for correspondence: RNDr. Vûra Lusková, PhD. Institute of Vertebrate Biology AS CR Department of Ichthyology, Kvûtná 8, 603 65 Brno, Czech Republic Phone: +420 5 4342 2527 Fax: +420 5 4321 1346 E-mail: [email protected] http://www.vfu.cz/acta-vet/actavet.htm The present paper is a sequel to an earlier contribution devoted to the effect of diazinon on the haematological indices in common carp (Svoboda et al. 2001). Here we present the results of our assessment of the effect of diazinon on the biochemical blood plasma profile in common carp. Materials and Methods The blood plasma of carp (Cyprinus carpio L.) one till two years aged (K1-2 ) was examined at the end of a 96hour test of acute toxicity of Basudin 600 EW at a concentration of 32.5 mg.l-1, an organophosphorous pesticide containing 600 g.l-1 diazinon substances as a toxicant. The Basudin 600 EW concentration used is the LC50 of this substance for carp of that age category. At the same time, a biochemical examination involved a control group of carp that was a part of the test. The test was carried out in a semistatic way, the bath being exchanged every 24 h. The basic physical and chemical indices of diluting water used in this acute toxicity test were as follows: pH 7.82 ANC4.5 (alkalinity) 1.05 mmol .l-1; BNC8.3 (acidity) 0.03 mmol .l-1; CODMn 1.0 mg .l-1; NH4 ++ NH3 0.1 mg .l-1; NO3 11.56 mg.l-1; NO2 0.015 mg.l-1; PO4 30.01 mg.l-1; sum of Ca + Mg 14 mg.l-1. During the test the water temperature varied between 20.8 and 21.5 °C, water saturation with oxygen ranged from 90 to 100 %, pH from 7.60 to 7.85. The test was carried out in five aquariums 200 l in volume each, and each containing 10 K1-2 (2 controls, 3 aquariums containing Basudin 600 EW at a concentration of 32.5 ml.l-1). Biochemical analyses of blood plasma involved 15 specimens of control K1-2 (254 ± 48.6 g in weight) and 16 experimental ones (268 ± 46.7 g in weight). Blood was sampled by cardiac puncture. Heparin in amount of 50 IU sodium salt per 1 ml blood was used for stabilisation. After sampling the blood was centrifuged for 15 min at 400 g. The activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholinesterase (CHE) with substrate butyrylthiocholine, lactate dehydrogenase (LDH), creatine kinase (CK), alkaline phosphatase (ALP), acid phosphatase (ACP) and total protein (TP), glucose (GLU), lactate (LACT) and electrolyte (Na, K, Ca, P) concentrations were determined using the automatic analyser COBAS MIRA (Hoffmann, La Roche, Co. Switzerland) and using optimised tests of Boehringer Mannheim GmBH by means of spectrophotometer Varian DMS 200. For the determination of CK activities the plasma was diluted 5-10 times with a physiological solution. One-way ANOVA was used to compare the values of biochemical indices in the blood plasma of the control and experimental fish.