Demographic responses of Daphnia magna fed transgenic Bt-maize.
The food/feed quality of a variety of genetically modified (GM) maize expressing Cry1Ab Bt-toxin was tested over the life-cycle of Daphnia magna, an arthropod commonly used as model organism in ecotoxicological studies. Demographic responses were compared between animals fed GM or unmodified (UM) near isogenic maize, with and without the addition of predator smell. Age-specific data on survival and birth rates were integrated and analysed using life tables and Leslie matrices. Survival, fecundity and population growth rate (PGR) data generally disfavoured transgenic Bt-maize as feed for D. magna compared to animals fed the unmodified (UM) near isogenic line of maize. Decomposition of age-specific effects revealed that the most important contributions to a reduced PGR in the GM-fed group came from both fecundity and survival differences early in life. We conclude that juvenile and young adult stages are the most sensitive experimental units and should be prioritized in future research. These stages are often omitted in toxicological/ecotoxicological studies and in feeding trials.
Genøk, Center for Biosafety, The Science Park, P.O. Box 6418, 9294, Tromsø, Norway. thomas@genok.org
Thomas
T
Bøhn
Terje
T
Traavik
Raul
R
Primicerio
D000821:Animal Feed / Q000633:toxicity*; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D003710:Demography; D004032:Diet; D004731:Endotoxins / Q000378:metabolism / Q000633:toxicity*; D006460:Hemolysin Proteins / Q000378:metabolism / Q000633:toxicity*; D007306:Insecticides / Q000378:metabolism / Q000633:toxicity*; D030821:Plants, Genetically Modified; D015996:Survival Rate; D003313:Zea mays / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis