Inulin-storing potatoes had higher alkaloid content and pigs fed on
them had reduced daily weight gain.
Manipulated Organism:
Potato (Solanum tuberosum).
Inserted Transgenes and Target Effect:
Two genes for two enzymes, 1-SST and 1-FFT, from the globe artichoke
(Cynara scolymus) to give potato plants the ability to synthesize
and to store inulin as a carbohydrate rather than starch. The inulin
content in the transgenic tubers was 50g/kg in the dry matter. "The
tubers were intended to be used as a prebiotic functional food in human
nutrition" (p. 20).
Goal of This Study:
Investigate whether the transgenic potatoes showed, first, any other
differences in substance composition and amounts from the unmanipulated
parent variety and, second, whether pigs, as a model for humans, whose
feed included these transgenic potatoes differed from pigs fed with the
unmanipulated parent variety.
Results of This Study:
There were no significant differences in mineral and amino acid content;
starch content decreased in correlation with increase of inulin amounts,
"indicating the storage capacity of carbohydrates was not affected by
genetic modification" (p. 20). However, there were a number of nontarget
effects:
-
Total alkaloid content of the transgenic potatoes was significantly higher
(25%) than in the unmanipulated parent variety.
-
"Digestibility depressions of some nutrients . . . were detected and
correspondingly lower energetic feeding value was measured" in pigs fed
transgenic potatoes (p. 21).
Daily weight gain of pigs fed transgenic potatoes was lower (43 g per
day).
-
Transgenic potatoes had lower silage production potential.
Additional Comments:
The authors state that the "results confirm that substantial genetic
modifications might be associated with altered concentrations of
undesirable substances, and therefore increased attention should be paid
to this fact [through] additional safety studies" (pp. 20-1).
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:
Institute of Animal Nutrition, Federal Agricultural Research Center
(FAL), Braunschweig, Germany; Institute of Organic Farming, FAL,
Westerau, Germany.
Funding:
Not mentioned.
Product Status:
Not on the market as of 2008.
Copyright 2008 The Nature
Institute.
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