Pigs fed GM canola had reduced daily weight gain and the canola had
higher concentrations of undesirable substances.
Manipulated Organism:
Canola (Brassica napus ssp. Oleifera, cv. Drakkar), also known
as oilseed rape.
Inserted Transgene and Target Effect:
The acyl-thioesterase gene from the cigar flower (Cuphea
lanceolata) with the aim of increasing canola's ability to produce
more myristic acid and palmitic acid at the expense of oleic acid. The
transgenic canola plants would be grown to harvest these two substances
for technical purposes.
Goal of This Study:
Since the transgenic canola would also be used as animal feed, the
scientists investigated whether it affects pigs any differently from
the unmanipulated parent variety of canola.
Results of This Study:
Although the nutrient content of the transgenic seeds was not
significantly different in the nutrients studied, the daily weight gain
in pigs fed transgenic canola seeds as part of their diet was reduced by
5.4% (37g) per day. This was "associated with higher concentrations of
undesirable substances" (p. 20) in the transgenic canola. In particular,
the total amount of glucosinolates was significantly higher (44%) than
in controls. (Glucosinolates are undesirable in such high concentrations
because they transform into natural pesticides when cells are broken open,
as happens during digestion.) The higher concentration of glucosinolates
was unexpected.
Additional Comments:
The authors state: "these results are an excellent example that
genetically modified plants with output traits need a complete
compositional and nutritional assessment" (p. 20). In other words, it is
not enough just to test for nutrients and a few known harmful substances
("anti-nutrients").
Source:
Flachowsky G., K. Aulrich, H. Böhme, and I. Halle (2007). "Studies
on Feeds from Genetically Modified Plants (GMP) - Contributions
to Nutritional and Safety Assessment, " Animal Feed Science and
Technology vol. 133, pp. 2-30.
Author Affiliations:
Affiliations: Institute of Animal Nutrition, Federal Agricultural Research
Centre (FAL), Braunschweig, Germany; Institute of Organic Farming, FAL,
Westerau, Germany.
Funding:
Not reported.
Product Status: Not on the market as of 2008.
Copyright 2008 The Nature
Institute.
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