Inulin-storing potatoes had higher alkaloid content and pigs fed on
them had reduced daily weight gain.
Potato (Solanum tuberosum).
Inserted Transgenes and Intended 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
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
Transgenic potatoes had lower silage production potential.
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).
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.
Institute of Animal Nutrition, Federal Agricultural Research Center
(FAL), Braunschweig, Germany; Institute of Organic Farming, FAL,
Not on the market as of 2008.
Copyright 2008 The Nature