<p style="text-align: justify;"><b>Dietary Exposure</b></p>

<p style="text-align: justify;">Humans consume relatively little whole kernel or processed maize, compared to maize-based food ingredients. Maize is a raw material for the manufacture of starch, the majority of which is converted to a variety of sweetener and fermentation products, including high fructose syrup and ethanol. Maize oil is commercially processed from the germ. These materials are components of many foods including bakery and dairy goods, and the human food uses of grain from TC-6275 are not expected to be different from the uses of non-transgenic field maize varieties. As such, the dietary exposure to humans of grain from insect resistant hybrids, such as TC-6275, will not be different from that for other commercially available field maize varieties.</p>

<p style="text-align: justify;"><b>Nutritional Data</b></p>

<p style="text-align: justify;">Forage and grain from TC-6275 maize were analyzed for nutritional composition and compared to the nutritional composition of the non-transgenic control (the near-isoline CHPH09B/2MW). In forage, harvested at the dough (R4) stage, there were no significant differences in the mean levels of protein, acid detergent fibre (ADF), neutral detergent fibre (NDF), and phosphorus between TC-6275 and the non-transgenic control line. The mean level of fat in TC-6275 was lower than the control line, but was within the range of values reported in the scientific literature. Conversely, the mean levels of ash, carbohydrate and calcium in TC-6275 were greater than those of the control line, but were also within the range of values reported in the literature.</p>

<p style="text-align: justify;">Grain from TC-6275 and the control line were analyzed for levels of proximates (fat, protein, crude fibre, ADF, NDF, ash and carbohydrates), fatty acids, amino acids, minerals, and vitamins A, B1, B2 and folic acid. TC-6275 was found to have lower levels of crude fibre, ADF, linoleic acid, lysine, calcium, zinc, vitamin B1 and folic acid, while levels of oleic acid, isoleucine, arginine, glutamic acid, praline, iron, vitamin A and E were higher compared to the control line. Although differences were noted, these values remained within the normal range of variation reported for maize grain, with the exception of vitamin A. The levels of vitamin A were higher than the range of values reported in the literature; however, this discrepancy was attributed to different assay methods, rather than genotype.</p>

<p style="text-align: justify;">The levels of the antinutritional compounds phytic acid and trypsin inhibitor were analyzed in TC-6275 and the control line. Statistically significant differences in the levels of these compounds were observed: levels of phytic acid were greater, and those of trypsin inhibitor were less compared to the control line. However, theses differences were within the range reported in the literature for conventional maize lines.</p>

<p style="text-align: justify;"><b>Toxicity and Allergenicity</b></p>

<p style="text-align: justify;">The Cry1F protein expressed in TC-6275 is similar, in biochemical properties and biological activity to that expressed by the maize line TC1507. This was substantiated by data, provided by Dow Agro Sciences, to demonstrate the equivalency in terms of biochemical properties and biological activity, of Cry1F in TC-6275 to that in TC1507. The following are results from investigations on the potential for toxicity and allergenicity of Cry1F expressed maize in TC1507.</p>

<p style="text-align: justify;">The amino acid sequence of Cry1F was compared to the sequences of known toxins and allergens using public protein sequence databases. The amino acid sequence of Cry1F was not homologous with any known toxin or allergen. Results from in vitro digestibility studies using simulated gastric fluids demonstrated rapid digestion of Cry1F: 98% of the protein was degraded within half a minute, and complete digestion was observed in less than 5 minutes. Cry1F is heat labile, as demonstrated by the loss of activity to neonate tobacco budworm after 30 minutes at 75C. The mammalian toxicity of the Cry1F protein was evaluated from results of an acute oral toxicity study. Mice were fed a dose of Cry1F (576 mg/kg body weight) which was well above the highest measured expression level in TC6275 grain (<i>i.e. </i>, 1.68 mg/kg). No toxic effects were observed in the mice when fed at this dose, which was estimated to be 26,000-fold greater to what humans would be exposed based on the typical consumption of foods derived from TC-6275 maize grain.</p>

<p style="text-align: justify;">The PAT protein in TC-6275 was also evaluated for its potential for toxicity and allergenicity. An amino acid sequence homology search no similarity to known toxins and allergens. Results of previous in vitro digestibility studies on the PAT protein demonstrated its rapid digestibility in simulated gastric fluids. These results, and those of other studies previously submitted to regulatory authorities in support of the safety of PAT, substantiate its low potential for toxicity and allergenicity.</p>
