Background: This series contains brief reports on each of the "600 studies" held on the GENERA database, published at Bifortified.org, in the order in which they were listed on 18 Sept 2013. The general purpose is to counter the extraordinary claims that the entries on this list demonstrate the human food safety of GM crops. See the Introduction to this series [link].
Great Big List of Studies: Entry 14 – Apgar (Guthrie et al) 2004 [pdf link]
"T.A. Guthrie" is the lead author of the study, though attributed to G. A. Apgar on the list. Not sure why.
This study fed an experimental GM corn and control to 8 female pigs for 15 days, in a cross over design (4 pigs per treatment per period). The corn is not on US FDA approval lists – it doesn't seem to be commercialized. This study does not seem to have any direct relevance to the question of human food safety of commercial GM crops.
The corn had been engineered to contain a gene from e-coli bacteria, "glutamate dehydrogenase". The authors reported some significant differences in the amino acid content of the GM corn compared to a corn that did not contain this transgene cassette. I'm not sure if the comparison corn was a negative segregant of the transgenic event, or whether it was the parent/isogenic line that had been used for the GM transformation.
With the small number of animals they lacked statistical power for a number of variables. They reported no other statistically significant findings on the variables associated with digestibility and nitrogen utilization, nor on weight or average daily gain, despite the mildly high protein levels in the GM feed. It could be observed that the group of pigs with the lightest initial weight gained the most weight over the period, regardless of feed. Perhaps this variable played into the outcome. The authors reported that the results suggested nutritional equivalence.
To alleviate boredom in their 1.22 x 2.43m smooth-walled crates the pigs were given a 5 x 30 cm piece of pvc pipe to play with.
More could be found out about the crop and genetic characteristics but I don't think the deeper research would contribute further for the purpose here. Always happy to hear more.