Toxigenic and pathogenic activity of aspergillus flavus in the rat

Abstract

Metarhizium anisopliae which obtained from Department of Agriculture Extension, Ministry of Agriculture and Cooperatives was re-examined and identified as Aspergillus flavus group. Acute toxigenic and pathogenic activity of A. flavus and its crude toxin were studied in rats and mice. General signs and symptoms were observed and the number of dead animals were recorded with a period of 7 days after administration. Rats intraperitoneally (I.P.) injected with spore suspension were found to be no significant changes in hematological values except in the number of leucocyte increasing significantly. The plasma biochemical parameters including protein, BUN, albumin, globulin, PGOT and PGPT activity were in normal ranges, whereas body weight gain was slightly decreased. Some treated rats were inactive (but sensitive to noice) with ataxia, fine tremors, loss right reflex and log rolling motion. In rats and mice administered intraperitoneally with crude toxin were shown to have similar clinical symptoms as spore suspension treated rats but more severe and rapid onset of action than those occurred in spore suspension treated rats. The trembling continuously exhibited for 1-2 days in survival animals. Whereas, the responses of rats and mice to intragastric administration consisted of only temporary inactive and mild tremors for a short duration. Histopoathological changes were not found in both intraperitoneal and intragastric administration. It is likely that crude toxin contained neurotoxic compounds. Time-course effects of crude toxin on plasma biochemical parameters and hematocrit were investigated in rat intraperitoneally injected at dose of 125 mg/kg BW at vairous time intervals of 0-24 hours. Plasma concentrations of albumin and globulin were not significant difference. Hematocrit value was singificantly increased within 6 hours after treatment, while, plasma protein concentration was declined. The elevation of PGOT and PGPT activity occurred within 6 and 18 hours after treatment respectively. Subacute pathogenicity of A. flavus was studied in rats intraperitoneally or intrathoracicly treated with spore suspension. No significant difference in hematological values were observed and plasma biochemical values were in normal ranges. A. flavus and its crude toxin were also induced mortality in rhinoceros beetles, Oryctes rhinoceros. These results indicate that A. flavus can produced mycotoxins which contain neurotoxin.