Mice fed with transgenic weevil-resistant peas showed immune reaction
while pigs and chickens had reduced starch digestion.
Manipulated Organism:
Pea (Pisum sativum L.).
Inserted Transgenes and Target Effect:
Gene for the enzyme alpha-amylase inhibitor 1 (αAI),
derived from the common bean (Phaseolus vulgaris L), cultivar
Tendergreen. The genetically altered peas produced the enzyme αAI and were
protected against the pea weevil in field trials. The enzyme is produced
naturally by the common bean, which is a close relative of the pea.
Goal of These Studies:
The studies reported here were carried out as part of a risk assessment
process in Australia.
Nontarget Effects:
-
The transgenic enzyme underwent in peas, as it does in beans, so-called
post-translational changes, which alter the enzyme's structure. But,
the post-translational changes in transgenic peas were different from
those that occur in beans.
-
Mice fed the transgenic peas showed an immune response, which was not
the case when they were fed Pinto beans, indicating that the reaction was
somehow related to the transgene and or its integration into the pea. The
mice became predisposed to a specific inflammatory reaction (CD4+ Th2-type
inflammation).
-
Starch digestion in the small intestines was markedly decreased in pigs
and chickens fed a diet including the transgenic peas.
-
The growth rate of broiler chickens fed for forty days on a diet including
the transgenic peas was reduced by eleven percent.
Additional Comments:
The authors carried out these studies as part of a risk assessment
process by Australia's national science agency, the Commonwealth
Scientific and Industrial Research Organisation (CSIRO). Based on these
findings CSIRO discontinued the development of the transgenic peas (see
http://www.csiro.au/files/files/p8g7.pdf).
Sources:
Collins, C., P. Eason, F. Dunshea, T. Higgins, and R. King (2006). "Starch
But Not Protein Digestibility is Altered in Pigs Fed Transgenic Peas
Containing Alpha-Amylase Inhibitor," J. Sci. Food Agric.
vol. 86, pp. 1894-9.
Li, X., T. Higgins, and W. Bryden (2006). "Biological Response of
Broiler Chickens Fed Peas (Pisum sativum L.) Expressing the Bean
(Phaseolus vulgaris L.) Alpha-Amylase Inhibitor Transgene,"
J. Sci. Food Agric. vol. 86, pp. 1900-7.
Prescott, V., P. Campbell, A. Moore, J. Mattes, et al. (2005). "Transgene
Expression of a Bean Alpha-Amylase Inhibitor in Peas Results
in Altered Structure and Immunogenicity," J. Agric. Food Chem
vol. 53, pp. 9023-30.
Author Affiliations:
Government (Australia's national science agency, CSIRO) and universities
(U.S. and Australia).
Funding:
National Health Medical Research Council (Australia), Grains Research
and Development Corporation (Australian government and grain industry),
Paramount Seeds, Ltd.
Product Status:
Not on the market as of 2008. These studies were part of a governmental
risk assessment process in Australia; product developed was discontinued
on the basis of these studies (see above).
Copyright 2008 The Nature
Institute.
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