Table 2 Comparison of EFSA's scientific opinions on Monsanto's rat feeding study with NK603 maize

Sub-chronic (90-days) toxicity studies in rats fed maize NK603.

A published 90-day study in rats fed either maize NK603 as 11% or 33% of the diet, or a diet which to 11% or 33% was made up of non-GM maize grain having a comparable genetic background to maize NK603 (LH82 x B73), resulted in

No consistent differences in the measured clinical, biochemical, and histological parameters were noted for rats fed on non-GM or NK603 maize, except for slightly elevated levels of average corpuscular volume and average corpuscular haemoglobin in female rats administered with a high dose.

no consistent differences in the measured clinical, biochemical, and histological parameters, except for slightly elevated levels of average corpuscular volume and average corpuscular haemoglobin in female rats administered the high dose (Hammond et al., 2004).

Since both parameters were calculated from other data (hematocrit/red blood cells and haemoglobin concentration/red blood cells, respectively), and no other observations of treatment-related effects were made, the applicant suggests that an artifactual difference resulted from a slightly higher hematocrit or haemoglobin concentration and slightly lower red blood cell count at these sampling points.

Since both parameters are calculated (hematocrit/red blood cells and haemoglobin concentration/red blood cells, respectively), and no other observations of treatment-related effects were made, the applicant suggested that these statistical differences were artefacts resulting from a slightly higher hematocrit or haemoglobin concentration and slightly lower red blood cell count at this sampling.

Furthermore, the applicant concludes that these findings are of no biological significance.

Furthermore, it was pointed out that the observed difference in average corpuscular volume and average corpuscular haemoglobin had no biological relevance.

The Panel accepts this as a reasonable interpretation of the data. The Panel also found the doses chosen for the study (11% or 33% of diet) appropriate, as they did not distort the nutritional balance of the experimental animals. The standard rodent diet used by the test laboratory contains approximately 33% maize grain.

The EFSA GMO Panel finds the interpretation of the data acceptable. The EFSA GMO Panel also found the doses chosen for the study (11% or 33% of diet) appropriate, as they did not distort the nutritional balance of the experimental animals. The standard rodent diet used by the test laboratory contains approximately 33% maize grain.