Detection of genetically modified food in digesta and organs of rats fed transgenic potato

Transgenic potato plants harbouring cry1Ab gene, resistant to potato tuber moth, were used to examine the persistence of recombinant DNA and proteins in the digesta, gastrointestinal tract (GIT) tissues and visceral organs of rats in a 90-day feeding trial. Native plant DNA (chloroplastic gene, cp) and fragments of cry1Ab, nptII and nos promoter were tracked in rat organs and tissues by polymerase chain reaction (PCR). Although complete sequences (1200 bp) of cry1Ab gene and its decreased size (400 bp) were detected in the rat diets, the presence of these sequences was not confirmed by PCR analysis in the GIT contents of rats fed diets containing transgenic potato. Moreover, the 400 bp sequence of the nptII gene and 300 bp of the nos promoter were detected in the caecum, stomach and rectum contents of some rats fed transgenic potato; however, these sequences were not detected in all rats. Immunoassay showed that Cry1Ab protein is detectable in the GIT contents of rats fed transgenic potato, but quantitative assay by ELISA confirmed that the Cry1Ab protein was partially degraded (80.3–83.7% digestibility) after passing through the GIT. Similarly, ELISA assay of NPTII showed that the protein can be digested (76.8–84.36% digestibility) in the GIT. So, although ingested native and recombinant DNA and protein did not totally degrade in the GIT, it can be indicated that there is no need for concern about the effects of recombinant cry1Ab and nptII genes and their products on animals and humans.