Outcome of <i>Bt</i> transgenes and protein in corn silage, processed grains, and rumen content
Bibliographic record
Abstract
The environmental impact of transgenic plants has been questioned due to the potential persistence of proteins encoded by transgenes and horizontal gene transfer from the plant to gut microbes. The outcome of the encoded Bt [cry1A(b)] protein and transgene fragments (CaMV-35S, cry1A(b), bar, and bla) was monitored in silage and processed grains of two commercial Bt11 (NK N44-P4 Bt LL and NK N27-M3 Bt LL) and one Bt176 (Elite N09-K9 Bt) corn hybrids. The three Bt-corn hybrids with their non-Bt isolines were field-grown in four replicates. Seven 1.4-kg capacity mini-silos were prepared per plot and then opened after 1, 2, 4, 8, 16, 32, and 64 d. For each hybrid, two 500-kg plastic bag silos were also prepared, sampled after 30 and 198 d, and used in a feeding trial. In the mini-silos, the transgene fragments could no longer be amplified 32 d after ensiling. In the 500-kg plastic bag silos, the transgene fragments were still detectable in the three Bt hybrid silages 30 and 198 d after ensiling. At ensiling, the Bt protein concentration was 2.69, 4.11, and 0.83 µg g -1 DM for the Bt hybrids N44-P4, N27-M3, and N09-K9, respectively. After 64 d of fermentation in the mini-silos, the concentration was 4, 2, and 1% of the initial concentration, respectively, but was 16, 9, and 9% after 198 d in the 500-kg silos. After stringent processing treatments, transgene fragments, except the bla gene fragment, could still be amplified from corn grains. The Bt protein concentration in corn grain of the three Bt hybrids (initially 61, 239, and 21 ng g -1 DM, respectively) decreased by 35, 74, and 67%, respectively, after micronization, by 92, 98, and 89% after extrusion, and by 100% after flaking. After 7 d of feeding Bt corn silage to six dairy cows, Bt protein increased in ruminal digesta with higher concentrations for Bt11 hybrids than the Bt176 hybrid; in all cases, however, concentrations were very low in forage digesta and below detection levels in rumen fluid. Key words: Transgenic maize, silage, processed grains, genetically modified plants, Bacillus thuringiensis endotoxin
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".