Citation: Trabalza-Marinucci M, Brandi G, Rondini C, Avellini L,
C, Costarelli S, Acuti G, Orlandi C, Filippini G, Chiaradia E, Malatesta
M, Crotti S, Antonini C, Amagliani G, Manuali E, Mastrogiacomo
AR, Moscati L, Haouet MN, Gaiti A, Magnani M (2008).
A three year longitudinal study on the eVects of a diet containing genetically modiWed Bt176 maize on the health status and performance on sheep.
Livestock Sci 113:178–190
This study shows that a diet including insect-resistant Bt176 maize, fed to 53 ewes and their progeny for 3 years, did not have adverse effects on their health or performance and that no horizontal gene transfer to ruminal microorganisms or animal tissues was detected. No differences were observed regarding performance, reproductive traits, haematological parameters, antioxidant defences, lymphocyte proliferative capacity, phagocytosis and intracellular killing of macrophages, and ruminal microbial population characteristics between control and genetically modified (GM) maize-fed animals. Immune response to Salmonella abortus ovis vaccination was more efficient in GM maize fed sheep. No modifications of histological features of tissues were found; however, cytochemical analyses of ruminal epithelium by Ki67 staining provided evidence of proliferative activation of basal cells in all GM maize-fed ewes. Preliminary electron microscopy analyses of the liver and pancreas revealed smaller cell nuclei containing increased amounts of heterochromatin and perichromatin granules in GM maize-fed lambs. Meat protein content and water loss by cooking were slightly affected by the dietary treatment. No transgenic DNA was detected in tissues, blood, and ruminal fluid or ruminal bacteria. Longitudinal studies should be included in evaluation of food safety whenever possible and sheep may be a useful animal model for toxicological assessment.
This Italian feeding trial, in which some sheep were fed the controversial maize line Bt176 over a period of 3 years, appears to have been specifically designed and conducted in order to confirm the "no health risk" hypothesis. In 2002-2005 scientists at the University of Perugia, with funding from the Italian Ministry of Health, conducted a "longitudinal" study involving 106 breeding ewes, of which one group was fed on a diet containing Bt176 maize. The article has crucial information missing, and appears to be systematically biased. The following points emerged in a reading of the text:
1. The preamble states: "There is a lack of long-term studies, performed on a high number of animals over several generations, aimed at evaluating the effects of genetically modified (GM) feeds on livestock species." It is implied that this paper will address this issue, but it does nothing of the sort. Only one generation of ewes was fed on the GM maize, and their lambs were apparently fed no GM at all, in spite of what the Abstract claims. The actual size of the test group is not given anywhere in the paper.
2. The quantity of GM feed fed to the test group of ewes was very small, at 5.6% of their diet, except during lactation, when the proportion increased to 19.4%. Overall, the test group was fed 17 times more hay than GM maize.
3. The researchers found important differences in 4 out of 30 investigated blood parameters (ie. 13.33 percent of parameters). Some items were very close to statistical significance (e.g. ALT, P=0.053; Platelet, P=0.060; WBC, P=0.056) and yet these results were effectively disregarded or dismissed.
4. The histological differences picked up between the control group of ewes and the test (GM) group are said to be 'preliminary' -- we suspect because the scientists on this part of the project were not allowed to perform a detailed or extended study on the histological samples.
5. The PCR cited for Bt176 is not reliable, as it does not give the GM maize used, only the genes in plasmids. This is a common method used by the GM industry in the falsification of results.
6. It is also useful to recall the following: Bt 176 was one of the GM inserts analysed by both French and Belgian scientists. The company Syngenta claimed the transgene is crylAb. Comparison with the public database revealed that the transgene has only 65% homology with the native crylAb, but 94% homology with a synthetic crylAc.
7. Following brief references to "cell nuclear modifications" and "functional modifications" the authors of the paper fail to consider the implications or causes in any detail. In their abstract they say: "No modifications of histological features of tissues were found; however, cytochemical analyses of ruminal epithelium by Ki67 staining provided evidence of proliferative activation of basal cells in all GM maize-fed ewes. Preliminary electron microscopy analyses of the liver and pancreas revealed smaller cell nuclei containing increased amounts of heterochromatin and perichromatin granules in GM maize-fed lambs."
In its investigation of these results GM Free Cymru discovered that
the original referees of this paper did express concerns about these
physiological changes, and asked for them to be investigated and
elucidated, but that the journal accepted the piece in any case for
publication. It therefore appears that the journal had no wish to
see this essential information in print. One has to wonder why.