Biosafety Analysis of Bacillus Thuringiensis Toxin Using Immunopathological Approach in Balb/C Mice
Opondo, Josephine A.
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For over 18 years, there has been an increased use of genetically modified foods for both human and livestock and for this reason, there has been a large number of scientific feeding studies carried out to try to find out how safe the GM foods are. The evidence, however, is still far from proving whether long-term consumption of genetically modified foods possess negative effects for human or animal health. This present study was carried out to analyze the safety of Bacillus thuriengiensis (BT) toxin fed to mice. Bacillus thuriengiensis is one of the organisms that has been widely used in transfection. BALB/c mice were used to determine the effect of the toxin on mice growth, weights of internal organs, differential count of white blood cells, plasma proteins concentration, and histopathology of internal organs. Double imunodiffusion test was used to test for immune sensitization to toxin. Weaning male and female mice were fed separately in 4 groups of 10 mice each (n=40).There was one control and three experimental groups. The control group was fed on normal ratio of mice pellets and water adlibitum daily for 90 days. Groups A, B and C mice were fed on 10mg/kg, 30mg/kg and 50mg/kg of Bacillus thuriengiensis (BT) toxin as well as mice pellets and water adlibitum for the same 90 day experimental period. Body weights were recorded for individual mice on weekly basis. Blood was collected by cardiac puncture into EDTA BD vacutainer blood collection tubes. Tissue samples of internal organs were oBtained for histopathological examinations. There were no significant differences on mice body weights (p>0.05) between the Bacillus thuriengiensis (BT) fed and controls, there was a significant difference in the mean weight of spleen (p<0.05), of mice fed 30mg/kg of toxin (Group B), compared to other group, the mean weight of the spleen was less. The automated blood count results showed a significant difference in the counts of neutrophils in the groups fed on Bt toxin (50mg/kg) compared to control, (p<0.05) which were fed no Bt toxin. There was also a significant difference in the mean counts of white blood cells from group fed on 10mg/kg of Bacillus thuriengiensis (BT) toxin compared to the control. These proportions were significantly different (P<0.05) with 30mg/kg, 50mg/kg having significantly higher monocyte percentage. Liver tissue from mice in group C showed moderate congestion, spleen from mice fed 30mg/kg of toxin showed reactive white pulp and slight atrophy, kidney tissue section from mice in group A showed congestive glomerilitis while lung tissue from mice fed on 50mg/kg Bacillus thuriengiensis (BT) toxin showed signs of bronchopneumonia. Anti Bt toxin antibodies were detected in the mice group fed on 50mg/kg bwt of Bt toxin. This result shows there was immune sensitization by the toxin which may result in hypersensitivity following consumption of GMO foods. Therefore further safety tests on Bacillus thuringiensis toxin transfected foods to be carried out to determine its effects on mice health when administered for a longer periods.
- MST-Zoological Sciences