CONTRIBUTION TO THE PATHOBIOCHEMISTRY OF FURAZOLIDONE-INDUCED OXIDATIVE TOXICITY IN CHICKENS

Furazolidone (F) and its 5-nitrofuran derivatives, occasionally used i n veterinary and human medicine, are active against some microorganism s. This drug is considered to be mutagenic in special bacterial test s ystems. For public health reasons, the presence of F and other 5-nitro furan residues in edible mammalian and poultry tissues is strictly pro hibited. One-month-old experimental chickens (n=2x25) were fed 300 mg. kg-1 furazolidone for 3 days. A separate subgroup (n=11) was used for monitoring the kinetics of F in the blood plasma. Liver, lung and bloo d plasma samples taken from the experimental and control chickens afte r treatment were tested for glutathione-peroxidase (GSH-Px), glutathio ne reductase (GSH-R), catalase (CAT), superoxide dismutase (SOD) activ ities, reduced and oxidized glutathione (GSH and GSSG), malondialdehyd e (MDA), alpha-tocopherol (vE), selenium (Se) and F concentrations. On post-treatment day 2, SOD activity was significantly lowered in the l iver only. GSH-Px did not show any characteristic change in any of the tissues. CAT and GSH-R activities were significantly reduced in both organs until post-treatment day 5. At the same time, a significant dec rease of GSH accompanied by an increase in GSSG concentration, was fou nd in both tissues. Oral F treatment produced a transient increase in lipid peroxidation levels measured by the formation of MDA. Alpha-toco pherol content significantly decreased in both organs by post-treatmen t day 2. Se concentrations showed an insignificant rate of decrease. F concentration in the blood plasma reached its peak already 30 min aft er treatment. In the liver and lungs, F decreased sharply, reaching th e detection limit between days 2-5 after treatment. Furazolidone admin istered per os was found to alter the in vivo antioxidative enzymatic defense mechanisms. Increased lipid peroxidation and the concomitant o xidative stress may affect the functional integrity of the tissues.