Agriculture Reference
In-Depth Information
juvenile animals, medical treatments, etc.)
being dii cult to investigate, as well as
increasing the experimental complexity.
Hence, derived complex data sets are
currently not available, but it may be of
further interest to focus on GM-fed animals
with a premature or disturbed intestinal
barrier.
Finally, the short-term 3-month trials
routinely performed have frequently been
discussed as not being sui cient with
regards to the potential chronic ef ects of
GM crops on food and health safety.
h erefore, a few long-term as well as multi-
generation studies have been initiated using
commercialized GM plants (Table 9.2). From
a recent review (Snell
et al
., 2012, see also
Chapter 8), one can summarize that available
long-term as well as multi-generation
studies performed with commercialized GM
crops do not decipher new adverse health
ef ects or signii cant biological mal-
regulations within the fed animals. It has
been stated i nally that long-term experi-
ments will not generate signii cant new
information, as has been provided previously
by extensive 90-day feeding rodent studies
(see Chapter 8).
degraded during digestion and will lose
most of their biological input (see also
Chapter 6).
To date, feeding animals with com-
mercialized GM crops cannot be stated as a
signii cant health risk, either for the
animals themselves or for the consumers
eating the secondary products produced
thereof.
However, based on the majority of
publications, a signii cant transfer of
recDNA and recProtein into animal organs,
and subsequently into secondary products
like meat, milk and eggs, appears highly
improbable. It may be stated that the
passage of feed DNA fragments across the
intestinal wall can be judged as a natural
event, though the likelihood of detecting
foreign DNA depends strongly on their
abundance in the ingested feed. h e
appearance of recDNA may change if higher
initial concentrations are present in feed; for
example, when introducing transplastome
crops. Finally, the absolute concentration of
GM material fed to animals, the animal
species and the organ-specii c distribution
of feed components have to be acknowledged
when considering the fate of ingested
transgenic material. It is state of the art that
a routine screening of secondary products
derived from animals fed commercialized
GM appears improbable. All recent
publications have shown that recDNA/
recProteins cannot be measured reliably
within organs or secondary products like
meat, milk or eggs derived from GM-fed
animals. Such scientii c observations are the
rationale for legal regulations currently not
A signii cant transfer of functional recDNA/
recProteins through the animal digestive
tract into meat, milk or eggs appears highly
uncertain and could not be quantii ed until
now (Fig. 9.1). As reviewed before, foreign
DNA/proteins are routinely processed and
Table 9.2.
Key long-term feeding studies (
4 weeks) performed with commercialized Bt maize; ordered
by duration of experiment.
Duration
(weeks)
recDNA/Protein
in animal tissues
Species
Event (GM)
Reference
188
Sheep
Cry1Ab (Bt 176)
None
Trabalza-Marinucci
et al
.,
2008
100
Cows
Cry1Ab (MON810)
None
Steinke
et al
., 2010
100
Cows
Cry1Ab (MON810)
None
Guertler
et al
., 2010
35
Bulls + cows
Cry1Ab (Bt 176)
None
Flachowsky
et al
., 2007
31
Hens
Cry1Ab (Bt 176)
None
Flachowsky
et al
., 2007
16
Pigs
Cry1Ab (MON810)
None
Walsh
et al
., 2012
