Effects of dietary transgenic poplar leaf pellets on performance and tissues in rabbits

Various studies have been conducted to evaluate the effect of Bt crops on animals. Insect-resistant bioassays have revealed that the chitinase-BmkIT combination could be used as a new pest-resistant gene source and might be a complementary alien gene source to the Bt toxin gene. So it is necessary to assay the effects of chitinase-BmkIT plants on animals.

Forty 40-day old New Zealand White Rabbits (Oryctolagus cuniculus) were fed for 60 consecutive days with formulated feed containing dehydrated poplar (Populus cathayana Rehd) leaves harbouring chitinase-BmkIT gene combination or untransformed counterparts, and the potential toxicological effects of transgenic leaves on rabbits were explored. The results of the growth study revealed no significant differences for daily weight gain, feed intake and feed conversion ratio where they were 101.6%, 99.2% and 97.8% of the treatment compared to the control, respectively. No obvious pathological change was observed in the small intestine, stomach, spleen, kidney, lung, heart, bladder, pancreas, prostate and ovary. Electron microscopy observations of liver cells and renal cells showed they were both normal in the two groups. No feed-derived chitinase, BmkIT and NPTII genes were found in small intestine, blood, or leg muscle samples although they were detected in the formulated feed.

We conclude that the processed poplar leaves with foreign chitinase-BmkIT genes had no obviously harmful effects on rabbits.