GMO pig feeding trials – the data

By Jason Major

TechNyou

In reference to the news story I posted this morning about the feeding trials of pigs with Bt corn, the kind people from Teagasc has supplied me with some proceedings and slide presentations from this research – see below.

I will appreciate anyone’s thoughts on the study, their analysis, it implications and any shortcomings in the research methodology and initial results, etc,

I mentioned that I thought the data was unpublished. It turns out that part of the research – the short-term feeding stuff – has been published in the British Journal of Nutrition and is now available for review (Walsh et al., 2011).

Links to

Proceeding paper

Pig_Conference_Proceedings2011

Slide presentation

8_GMSAFOODSlidePresentation

Further Teagasc research 

Hanging questions and caveats

The proceedings paper doesn’t explicitly say if the GM and non GM Bt corn used in the trials were exactly the same cultivars – see following extract:

The Bt maize was grown in a neighbouring plot to the non-GM maize counterpart under identical environmental conditions in Valtierra, Navarra, Spain and the only difference between the two maize types was the Bt toxin.

This is important as two cultivars of corn can have radically different nutrient profiles, and levels of other compounds such as naturally occurring allergens, toxins and anti-nutrients. They were at least grown under identical conditions – something else that can significantly change these components.

These results only apply to the short and medium-term studies because the laboratory analysis for the long-term data is still happening. There a few lines of, “further research will need to be done to find out what is happening…” in the proceedings so we will have to wait and see. It is possible the long-term feeding analysis will provide some answers and clarification.

Couple of findings

I have yet to analyse the paper in detail and will probably wait until the long-term trial analysis is completed, but here a couple of the findings that jumped out.

Results from the medium-term study found that feeding Bt maize to pigs for 110 days had no effect on body weight, their average daily weight gain or their average daily feed intake.  But average daily feed intake (ADFI) was higher in pigs fed Bt maize during days 14-31 and overall from day 0-31. However, there was no difference in body weight between the two groups of pigs on day 31. Overall, feed efficiency was not affected by feeding Bt maize even though pigs fed Bt maize were less efficient on days 14-31 which was a consequence of higher feed intake by these pigs at that time. In other words weanling pigs were eating more during days 14-31 but their weight gain was the same as the conrol pigs.

If this difference in ADFI at days 14-31 is real (ie, it would need to be repeated and probably with a larger sample) then it would be interesting to know why this is happening.

In the slide presentation they present the finding that Bt maize may offer protection against an inflammatory response observed following non-GM maize consumption. I wonder if this is because maize is notoriously affected by a fungal toxin that is prevalent in corn damaged by insects?  Has anyone got any knowledge on this and if this may be a cause?

Update (30 Jan 2012)

Peadar Lawlor the head of the Irish component of the project got back to me re: the research and plans for publication. His response, “… we will have ~12 peer review papers from this work by the middle of this year. We have published in the British Journal of Nutrition, Animal, PLoS ONE etc. We will publish all our work from the project.” All links to papers and research updates will be posted on their website see Teagasc link above

And here is the link to their PLoS One paper

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