The fate of forage plant DNA in farm animals: a collaborative case-study investigating cattle and chicken fed recombinant plant material

The fate of ingested recombinant plant DNA in farm animals (cattle and chic ken) being fed a diet containing conventional maize or recombinant Bacillus thuringiensis toxin-maize (Bt-maize) is described. The probability of the detection by polymerase chain reaction of chloroplast-specific gene fragmen ts of different lengths (199 bp and 532 bp) and a Pt-maize-specific fragmen t [truncated version of CryIA(b)] is shown. First data indicated that only short DNA fragments (< 200 bp) derived from plant chloroplasts could be det ected in the blood lymphocytes of cows. In all other cattle organs investig ated (muscle, liver, spleen, kidney) plant DNAs were not found, except for faint signals in milk. Furthermore, Pt-gene fragments possibly recording th e uptake of recombinant maize, were not detected in any sample from cattle. However, in all chicken tissues (muscle, liver, spleen, kidney) the short maize chloroplast gene fragment was amplified. In contrast to this, no fore ign plant DNA fragments were found in eggs. Pt-gene specific constructs ori ginating from recombinant Pt-maize were not detectable in any of these poul try samples either.