Agriculture Reference
In-Depth Information
Feed from GM Plants in Asia
the same nutritional value as in their non-
transgenic counterparts in Bt rice and Bt
maize (Wang
et al
., 2002b; Li
et al
., 2004a).
h e total protein content and essential
amino acids were increased in maize carrying
the lysine-rich protein gene (Tang, 2008; see
also Chapters 3 and 4).
With increased plantings of GM plants and
their application in food and feed production,
more attention has been given to their
safety/risk assessment. In terms of
nutrition, the biosafety of GM plants is one
of the most important topics (see also
Chapter 3). Comparative approaches have
been utilized, i.e. food and feed are compared
with their non-GM counterparts in order to
identify intended and unexpected dif er-
ences, which subsequently are assessed with
respect to their potential impact on safety
for humans and animals, along with
nutritional quality. Generally, with regard to
food/feed from GM plants, scientists from
China have studied the key nutritional
components, acute toxicity, immune tox-
icity, allergenicity and reproductive toxicity
of introduced proteins (Cry1Ab, Cry1Ac,
cowpea trypsin inhibitor/CpTI, etc.) and
food (maize, rice, etc.). Feeding safety has
been assessed for imported transgenic
maize, soybean, rapeseed, etc.
Rice is one of the main crops in the world,
with 92% of the total area planted in Asia
and 31% in China. With the maturing of GM
rice technology, more ef ort has been put
into safety assessment. In addition, as an
important crop for both food and feed, the
biosafety assessment of GM maize is also an
important issue. h is review will introduce
the biosafety assessment of GM rice and
maize in China. h e assessment procedure
consists of i ve aspects, including substantial
equivalence of nutrition, nutritional assess-
ment in animals,
in vivo
and
in vitro
toxicological studies, allergenicity assess-
ment and horizontal transformation of the
introduced gene.
Li
et al
. (2004b) and Zhao
et al
. (2005)
evaluated the inl uence of GM rice
containing the disease-resistance gene,
Xa21
,
and the saline-tolerance gene,
codA
,
on the physiological metabolism and genetic
horizontal transformation in fed laboratory
rats. No toxicity or other adverse ef ects
were found in the transgenic rice group. Pigs
are good models for human nutrition
because of anatomical similarities to humans
(e.g. body size, skin, cardiovascular system
and urinary system) and because of
functional similarities (immune system and
gastrointestinal system). Chinese experi-
mental minipigs were used to assess rice
that was genetically modii ed with the
SCK
gene (a modii ed cowpea trypsin inhibitor
gene). Body growth (weight, height, body
length, thoracic circumference, etc.) and
feed intake of animals were recorded after
62 days of feeding. It was concluded that the
feeding value of GM rice and parental rice
was similar and no detrimental or un-
expected ef ects were observed in animals
fed the GM rice (Yang
et al
., 2005). h e
digestibility of protein and amino acids in
GM rice were compared to parental rice in
minipigs; except for the decreased digesti-
bility of lysine, there were no signii cant
dif erences in the apparent and true
digestibility of the other 17 amino acids
(Han
et al
., 2004).
Rice is eaten by humans after cooking.
h e ef ect of raw or cooked GM rice l our on
the development of silkworm larvae has
been compared. In contrast to normal feed,
the weight of silkworm larvae, the number
of grown silkworms, the number of cocoons,
the weight of cocoons and cocoon layers at
dif erent periods were signii cantly less or
delayed in the group fed raw GM rice. h ere
nutrition
Studies were conducted to assess whether
the key nutrients (carbohydrates, protein,
amino acids, key minerals and vitamins) in
transgenic plant components used for feed
or food had been changed. h e results found
