Contents - Faperta

450 Biotechnological Approaches for Pest Management and Ecological Sustainability
of Cry1Ab protein were detected in the gastrointestinal contents, but not in the liver, spleen,
kidney, muscle, or mesenteric lymph nodes (Chowdhury et al., 2003). No lesions were
observed pathologically. Cry1Ab protein in the feces was degraded quickly at atmospheric
temperature, suggesting that only trace amounts of Cry1Ab protein survived passage
through the gastrointestinal tract, but were not transferred to liver, spleen, kidney, lymph
nodes, or muscles. Fragments of transgenic and endogenous plant DNA as well as Bt Cry1Ab
protein were not detected in chicken breast muscle samples from animals fed MON 810
(YieldGuard) ( Jennings et al., 2003). A 396-bp fragment of the chicken ovalbumin (ov) gene
used as a positive control was amplifi ed from all the samples showing that the DNA preparations
were amenable to PCR amplifi cation. By using a competitive immunoassay with
a limit of detection of approximately 60 ng of Cry1Ab protein per gram of chicken muscle,
neither the Cry1Ab protein nor immunoreactive peptide fragments were detectable in the
breast muscle homogenates from chickens fed YieldGuard.
Protease Inhibitors
Rats fed on purifi ed cowpea trypsin (EC 3.4.21.4) inhibitor in a semisynthetic diet based on
lactoalbumin (10 g inhibitor kg1 ) for 10 days showed a moderate reduction in weight gain
in comparison with controls, despite identical food intake (Pusztai et al., 1992). Although
most of the cowpea trypsin inhibitor (CpTI) was rapidly broken down in the digestive
tract, its inclusion in the diet led to a slight, though signifi cant, increase in the nitrogen
content of feces, but not of urine. Accordingly, the net protein utilization in rats fed on
inhibitor-containing diets was also slightly lower, while their energy expenditure was elevated.
The slight antinutritional effects of CpTI were probably due mainly to the stimulation
of growth and metabolism of the pancreas. Thus, the nutritional penalty for increased
insect resistance after the transfer of the cowpea trypsin inhibitor gene into food plants is
quite low in the short term.
Lectins
The level of Galanthus nivalis L. lectin expression that provides insecticidal protection for
plants did not reduce the growth of young rats, and showed negligible effect on weight
and length of the small intestine, even though there was a slight hypertrophy of this tissue
(Pusztai et al., 1996). However, the activity of brush border enzymes was affected. Sucraseisomaltase
activity was nearly halved, and those of alkaline phosphatase and aminopeptidase
increased signifi cantly. Incorporation of N-acetylglucosamine-specifi c agglutinins from
wheat germ (WGA), thorn apple, Datura stramonium L., or nettle, Urtica dioica L. rhizomes
in the diet at the level of 7 g kg1 reduced the apparent digestibility and utilization of dietary
proteins and the growth of rats, with WGA being the most damaging (Pusztai et al., 1993).
As a result of their binding and endocytosis of the epithelial cells of the small intestine, all
three lectins interfered with metabolism and function to varying degrees. WGA also induced
hypertrophic growth of the pancreas and caused thymus atrophy. Transfer of WGA genes
into crop plants has been advocated to confer resistance to insect pests. However, the
presence of this lectin in the diet may harm higher animals at concentrations required to
be effective against most insect pests.
Changes in Chemical Profile/Secondary Metabolites
Comparative analysis of genetically modifi ed crops and the conventionally bred crop plants
has been suggested to monitor the changes in secondary metabolites, assuming that these