Fate of Maize Intrinsic and Recombinant Genes in Calves Fed Genetically Modified Maize Bt11

Abstract

The presence of maize intrinsic and recombinant cry1Ab genes in the gastrointestinal (GI) contents, peripheral blood mononuclear cells (PBMC), and visceral organs of calves fed genetically modified Bt11 maize was examined by PCR in a subchronic 90-day performance study. Samples were collected from six Japanese Black/Holstein calves fed Bt11 maize and from six calves fed non-Bt maize. Fragments of maize zein (Ze1), invertase, chloroplast, and cry1Ab were detected inconsistently in the rumen fluid and rectal contents 5 and 18 h after feeding. The chloroplast DNA fragments of ribulose-1,5-bisphosphate carboxylase/oxygenase and tRNA were detected inconsistently in the PBMC, the visceral organs, and the longissimus muscle, while the cry1Ab gene was never detected in PBMC or in the visceral organs. These results suggest that feed-derived maize DNA was mostly degraded in the GI tract but that fragmented DNA was detectable in the GI contents as a possible source of transfer to calf tissues. These results also suggest that the recombinant cry1Ab genes were not transferred to the PBMC and tissues of calves fed Bt11 maize.

Fate of recombinant DNA and Cry1Ab protein after ingestion and dispersal of genetically modified maize in comparison to rapeseed by fallow deer (Dama dama)

“…The transfer of DNA fragments to viscera and concomitantly their detection seems to depend on the fragment size and the number of gene copies. Our results are similar to findings in feeding studies with calves (Chowdhury et al 2004) where small DNA fragments (226 bp) of the rubisco gene were found in liver, spleen, kidney, muscle and lymph nodes. Chowdhury et al (2004) detected 242-bp fragments of the maize-specific zein gene in GI contents of calves fed with transgenic (Bt11) or nonBt maize.…”

“…Our results are similar to findings in feeding studies with calves (Chowdhury et al 2004) where small DNA fragments (226 bp) of the rubisco gene were found in liver, spleen, kidney, muscle and lymph nodes. Chowdhury et al (2004) detected 242-bp fragments of the maize-specific zein gene in GI contents of calves fed with transgenic (Bt11) or nonBt maize. However, neither in studies by Einspanier et al (2001) nor in investigations by Chowdhury et al (2004) were cry1Ab gene fragments detected in ruminant tissue samples, suggesting that the copy number is the main limiting factor in the traceability of the transgenic component.…”

“…cattle, poultry and pigs, were carried out (Chowdhury et al 2003a;Jennings et al 2003;Phipps et al 2003). Studies conducted with cows have illustrated that plant-derived and recombinant DNA and protein are degraded throughout the digestive tract (Chowdhury et al 2004;Einspanier et al 2004;Lutz et al 2005). However, no or little information is available about wildlife feeding on GM plants.…”

Detection of transgenic maize Cry1Ab protein subjected to ruminal digestion

“…A research group from Japan detected the Cry1Ab and Cry9 genes in the digestive contents throughout the gastrointestinal tract of calves and pigs in two separate studies (Chowdhury et al, 2003b(Chowdhury et al, , 2004. The DNA of both Bt-toxin genes was detected experimentally in the faecal samples of more than 25% of pigs and 50% of calves.…”

Safety Evaluation of Bt Plants

“…In response to this concern, many studies on the fate of transgenic plant DNA and proteins have been conducted. Chowdhury et al found that Cry toxin and cry gene were not totally degraded and were detected in gastrointestinal contents, but not in peripheral blood and visceral organs by immunological tests and PCR when Bt corn was fed to calves and pigs [9][10][11][12] . Wiedemann et al examined the time-dependent ruminal degradation of transgenic DNA and Cry toxin using an in situ technique in which nylon bags filled with test corn samples were positioned within the rumen of rumen-cannulated cows.…”