Cytotoxic Effects of Aflatoxin B1 Standard in Relation to Aflatoxin Extracts from South African Compound Feeds on Human Lymphocytes

Cytotoxicity testing of aflatoxin (AF) on the viability of cells grown in cultures can be widely used to predict the potential toxic effects of AF in animals. To this end, an in vitro experimental study was conducted to ascertain the toxic effects of AF extracts obtained from compound feeds in South Africa on human lymphocytes in comparison to that of an AFB1 standard. The approach adopted was on the basis of viable cells reducing methyl tetrazolium bromide (MTT) from blue to a purple formazan dye, which was then spectrophotometrically quantified to provide the rate of cytotoxicity. 

Data obtained indicated no cytotoxic response in control cells, as the viability of cells without treatment with AF standard or methanolic extracts of AF extracts [negative control] using methanol as the reconstituting solvent, was 99.9% after 24 hrs. of incubation. However, cell viability significantly (p<0.001) decreased upon exposure to AF extracts especially for poultry feed. This was influenced by both the dose and duration of exposure, which was much more pronounced when the cells were exposed to AFB1 standard than for all the AF extracts tested. This implies that these feeds on exposure to AF can greatly influence animal health with respect to both the contamination dose and exposure time.