Effects of Feeding Bt Maize to Sows during Gestation and Lactation on Maternal and Offspring Immunity and Fate of Transgenic Material
We aimed to determine the effect of feeding transgenic maize to sows during gestation and lactation on maternal and offspring immunity and to assess the fate of transgenic material.
On the day of insemination, sows were assigned to one of two treatments (n = 12/treatment); 1) non-Bt control maize diet or 2) Bt-MON810 maize diet, which were fed for ~143 days throughout gestation and lactation. Immune function was assessed by leukocyte phenotyping, haematology and Cry1Ab-specific antibody presence in blood on days 0, 28 and 110 of gestation and at the end of lactation. Peripheral-blood mononuclear cell cytokine production was investigated on days 28 and 110 of gestation. Haematological analysis was performed on offspring at birth (n = 12/treatment). Presence of the cry1Ab transgene was assessed in sows’ blood and faeces on day 110 of gestation and in blood and tissues of offspring at birth. Cry1Ab protein presence was assessed in sows’ blood during gestation and lactation and in tissues of offspring at birth. Blood monocyte count and percentage were higher (P<0.05), while granulocyte percentage was lower (P<0.05) in Bt maize-fed sows on day 110 of gestation. Leukocyte count and granulocyte count and percentage were lower (P<0.05), while lymphocyte percentage was higher (P<0.05) in offspring of Bt maize-fed sows. Bt maize-fed sows had a lower percentage of monocytes on day 28 of lactation and of CD4+CD8+ lymphocytes on day 110 of gestation, day 28 of lactation and overall (P<0.05). Cytokine production was similar between treatments. Transgenic material or Cry1Ab-specific antibodies were not detected in sows or offspring.
Treatment differences observed following feeding of Bt maize to sows did not indicate inflammation or allergy and are unlikely to be of major importance. These results provide additional data for Bt maize safety assessment.
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In some previously reported cases, transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have suppressed insect pests not only in fields planted with such crops, but also regionally on host plants that do not produce Bt toxins. Here we used 16 years of field data to determine if Bt cotton caused this “halo effect” against pink bollworm (Pectinophora gossypiella) in six provinces of the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010. We found that Bt cotton significantly decreased the population density of pink bollworm on non-Bt cotton, with net decreases of 91% for eggs and 95% for larvae on non-Bt cotton after 11 years of Bt cotton use. Insecticide sprays targeting pink bollworm and cotton bollworm (Helicoverpa armigera) decreased by 69%. Previously reported evidence of the early stages of evolution of pink bollworm resistance to Bt cotton in China has raised concerns that if unchecked, such resistance could eventually diminish or eliminate the benefits of Bt cotton. The results reported here suggest that it might be possible to find a percentage of Bt cotton lower than the current level that causes sufficient regional pest suppression and reduces the risk of resistance.
Pink bollworm abundance on non-Bt cotton before and after adoption of Bt cotton.
Volledige artikel in Plos One.
Over the past 16 years, vast plantings of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have helped to control several major insect pests1, 2, 3, 4, 5 and reduce the need for insecticide sprays1, 5, 6. Because broad-spectrum insecticides kill arthropod natural enemies that provide biological control of pests, the decrease in use of insecticide sprays associated with Bt crops could enhance biocontrol services7, 8, 9, 10, 11, 12. However, this hypothesis has not been tested in terms of long-term landscape-level impacts10. On the basis of data from 1990 to 2010 at 36 sites in six provinces of northern China, we show here a marked increase in abundance of three types of generalist arthropod predators (ladybirds, lacewings and spiders) and a decreased abundance of aphid pests associated with widespread adoption of Bt cotton and reduced insecticide sprays in this crop. We also found evidence that the predators might provide additional biocontrol services spilling over from Bt cotton fields onto neighbouring crops (maize, peanut and soybean). Our work extends results from general studies evaluating ecological effects of Bt crops1, 2, 3, 4, 6, 12, 13 by demonstrating that such crops can promote biocontrol services in agricultural landscapes.
Genetically modified crops have allowed pesticide spraying to be reduced by almost half a million kilograms in the last 15 years. Eric Constantineau
Recent news reports claim one in ten Australians believe the world will end on December 21, 2012, based largely on internet gossip about the meaning of ancient stone carvings from the Mayans of Central America. Such is the disturbing power of frightening myths to influence human belief.
No wonder modern apocalyptic mythology about agriculture, sinister stories about pesticides and assertions that genetic engineering of crops break a biological taboo find a very receptive audience, especially among those who don’t ever go to a modern farm.
In truth, there’s a lot to feel good about in the way modern agriculture is shaping up to the big challenges of the present – reducing carbon emissions, preventing soil erosion and minimising any environmental damage by herbicides and pesticides.
Helping the environment
One of the most significant crop management improvements in recent times has been the increasingly common practice of sowing seeds by direct drilling them into the stubble of the previous season’s crop. This approach forgoes a massive amount of soil tillage with the plough. Such minimum-tillage or no-tillage farming means that much less diesel oil is used in tractors and carbon levels can buildup in the soil rather than be released to the atmosphere.
It’s been estimated that the carbon emission savings from introduction of genetically engineered crops that encourage no-till farming are equivalent to removing 19.4 bn kilogram of carbon dioxide from the atmosphere worldwide. This is equal to the carbon emissions savings from removing 8.6 million cars from the road for one year.
Minimal tillage farming also has several other benefits, such as better moisture retention in the soil and reduction in soil erosion.
Genetically modified insect protected cotton on the left, next to a closely related conventional cotton variety on the right which is showing the damage from heavy insect feeding pressure. Greg Kauter, Courtesy of Australian Cotton Growers Research Association Inc, Narrabri, NSW.
Klik hier voor het volledige Australische artikel.
Last week information was spread that Burkina Faso farmers have decided this year to stop planting Bt cotton. But, reacting to this news, Burkina Faso cotton companies indicate they were very surprised with this information
BURKINA FASO ABANDONS Bt COTTON: «We are surprised by the information» Monday, 14 May 2012.
Following the news, on Radio France Internationale (RFI), announcing that this year, Burkina Faso will stop growing BT cotton generally called GMO cotton, we had an interview with Dr. Dehou Dakuo, Director, Cotton production and development of SOFITEX, who expressed his surprise at the news. To him, it is not true as Burkina Faso is rather cultivating more than 200,000 hectares of the BT cotton seed. He however acknowledged that this year, for purity reasons, lesser seeds were distributed.
« Le Pays »: Burkina Faso woke up today to hear news on RFI announcing the cessation of the cultivation of the BT cotton this year. What is it in reality?
Dr Déhou Dakuo: we were also surprised by that information especially because at the moment we are holding our pre-seedling forums with our producers. The setting for the genetically modified cotton (GMC) as well as biological cotton seeds is 80% ready meaning most of the cotton producer groups have been supplied with BT cotton seeds. SOFITEX specifically (Editor’s note: there are two other cotton companies: SOCOMA and Faso Coton) expects to grow 200 to 300 thousand hectares of BT cotton during the 2012/2013 season. Just last week, Faso Coton went to the Kourouma delinting factory in Kenedougou to withdraw their stock of GMC seeds. I think it is the turn of SOCOMA to do the same this week. We are therefore very surprised to hear that Burkina Faso wants to stop growing BT cotton.
How can you explain the release of such information? Could it be a wrong source of information or a manipulation?
I cannot explain it. One thing is sure: it was false information. I spoke to many people in and outside the cotton industry in order to understand what really happened but no one was able to explain it. Unless there are other intentions behind the release of that piece of information by RFI, this year, a general evaluation of the cotton industry was conducted and the Association Interprofessionnelle du Coton du Burkina (AICB) held a press conference on the state of cotton growing in Burkina Faso. Documents are available and were disseminated. Things were transparent at that level.
De rest van het interview kun je hier lezen.
Hier vind je een artikel dat ook dieper ingaat op de kwestie (Frans).
…on Peripheral Immune Response and Digestive Fate of the cry1AbGene and Truncated Bt Toxin
The objective of this study was to evaluate potential long-term (110 days) and age-specific effects of feeding genetically modified Bt maize on peripheral immune response in pigs and to determine the digestive fate of the cry1Ab gene and truncated Bt toxin.
Forty day old pigs (n = 40) were fed one of the following treatments: 1) isogenic maize-based diet for 110 days (isogenic); 2) Bt maize-based diet (MON810) for 110 days (Bt); 3) Isogenic maize-based diet for 30 days followed by Bt maize-based diet for 80 days (isogenic/Bt); and 4) Bt maize-based diet (MON810) for 30 days followed by isogenic maize-based diet for 80 days (Bt/isogenic). Blood samples were collected during the study for haematological analysis, measurement of cytokine and Cry1Ab-specific antibody production, immune cell phenotyping and cry1Ab gene and truncated Bt toxin detection. Pigs were sacrificed on day 110 and digesta and organ samples were taken for detection of the cry1Ab gene and the truncated Bt toxin. On day 100, lymphocyte counts were higher (P<0.05) in pigs fed Bt/isogenic than pigs fed Bt or isogenic. Erythrocyte counts on day 100 were lower in pigs fed Bt or isogenic/Bt than pigs fed Bt/isogenic (P<0.05). Neither the truncated Bt toxin nor the cry1Abgene were detected in the organs or blood of pigs fed Bt maize. The cry1Ab gene was detected in stomach digesta and at low frequency in the ileum but not in the distal gastrointestinal tract (GIT), while the Bt toxin fragments were detected at all sites in the GIT.
Perturbations in peripheral immune response were thought not to be age-specific and were not indicative of Th 2 type allergenic or Th 1 type inflammatory responses. There was no evidence of cry1Abgene or Bt toxin translocation to organs or blood following long-term feeding.
Volledige artikel is hier integraal toegankelijk.
Plant varieties, weather and farming methods affect the maize ecosystem
For three summers in a row, Eva Schultheis and her team at RWTH Aachen University caught countless insects on the maize trial field and then identified the species in the laboratory. They wanted to find out whether the insect communities found in genetically modified Bt maize are different from those found in conventional maize. They found differences between the years and between individual maize varieties, but were unable to detect any influence of the genetic modification. Extensive investigations in the laboratory with the rice leaf bug, which was chosen as a representative species, also failed to find any negative Bt maize effects. GMO Safety spoke to Eva Schultheis about her research work.
Het volledige interview kun je hier nalezen.
Various published studies analyzed effects of Bt maize on nontarget insects. Two well-known studies focused on monarch butterflies (1) and on black swallowtails (2). The first, a note to Nature in 1999, was a laboratory study in which monarch caterpillars were fed milkweed leaves dusted with loosely quantified amounts of pollen from a single Bt corn variety. In the second study in 2000, black swallowtail caterpillars were placed different distances from a cornfield planted with a Bt corn variety different from that used in the 1999 study; populations were studied for effects of Bt for seven days. In the first study more monarch caterpillars died when they ate leaves dusted with Bt corn pollen versus leaves dusted with conventional corn pollen. In the second study, no negative effects of Bt pollen were found on numbers of swallowtail caterpillars.
Het volledige artikel met referenties vind je hier.
Given that the controversy over success and failure of Bt technology still exists, this paper discusses the available field studies that have addressed agro-economic questions of Bt cotton cultivation in India. Since a meta-analysis of studies can give only partial conclusions, owing to differences across study methodologies and coverage, this paper takes a different strategy, i e, looking not simply at differences between Bt farms and non-Bt farms, but at the experience of farmers before growing Bt and after switching to Bt. It also examines the more general problem of comparing field studies and suggests ways to use farmer behaviour as a proxy for settling different interpretations of agro-economic effects of the new technology. The study explains why there has been so much controversy given virtually universal adoption of Bt technology in cotton and concludes that in the battle of numbers around Bt cotton, those of the farmers have been curiously missing.
De volledige studie is hier raadpleegbaar en extreem aangeraden!