Reduced Fitness of Daphnia magna Fed a Bt-Transgenic Maize Variety
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Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize.
KeywordsGenetically Modify Clutch Size Genetically Modify Crop Nontarget Organism Genetically Modify Food
We would like to thank Dr. Chito Medina and farmers from the Iloilo district in the Philippines for providing the maize samples used in the experiments. We are grateful to Professor Kaare M. Nielsen for valuable discussions related to the experiments. We also thank Dr. Idun Grønsberg, Marte Albrigtsen, Julia Eggert, and Elisabeth Olsen at the GenØk Lab in Tromsø and Dr. Morten Johansen and Kriss Rokkan Iversen at the Norwegian College of Fishery Science for practical assistance during the experiments. The studies were supported by a grant (Project No. 154504) from the Research Council of Norway.
- Aeschbacher K, Messikommer R, Meile L, Wenk C (2005) Bt176 corn in poultry nutrition: physiological characteristics and fate of recombinant plant DNA in chickens. Poult Sci 84(3):385–394Google Scholar
- Brake J, Vlachos D (1998) Evaluation of transgenic event 176 “Bt” corn in broiler chickens. Poult Sci 77(5):648-653Google Scholar
- Clark JH, Ipharraguerre IR (2001) Biotech crops as feeds for livestock. Abstr Papers Am Chem Soc 222:U67Google Scholar
- Hilbeck A, Schmidt JEU (2006) Another view on Bt proteins: how specific are they and what else might they do? Biopestic Int 2(1):1–50Google Scholar
- James C (2006) Global status of commercialized biotech/GM crops. ISAAA Brief No. 35. 2006. ISAAA, Ithaca, NYGoogle Scholar
- Pusztai A (2002) Can science give us the tools for recognizing possible health risks of GM food? Nutr Health 16:73–84Google Scholar
- Roff DA (2002) Life history evolution. Sinauer Associates, Sunderland, MAGoogle Scholar
- Rosi-Marshall EJ, Tank JL, Royer TV et al (2007) Toxins in transgenic crop byproducts may affect headwater stream ecosystems. Proc Natl Acad Sci USA 104(41):16,204–16,208Google Scholar
- Tapp H, Stotzky G (1995) Insecticidal activity of the toxins from Bacillus-Thuringiensis subspecies kurstaki and tenebrionis adsorbed and bound on pure and soil clays. Appl Environl Microbiol 61(5):1786–1790Google Scholar
- Twombly S, Clancy N, Burns CW (1998) Life history consequences of food quality in the freshwater copepod Boeckella triarticulata. Ecology 79(5):1711–1724Google Scholar