705 Evaluation of the compositional and nutritional values of mCry1Ac corn and maroACC corn in growing pigs

Abstract

The aim of this study was to evaluate the nutrient digestibility in growing pigs of 2 transgenic corn lines containing the mCry1Ac gene from a Bacillus thuringiensis strain (BT) and the maroACC gene from Agrobacterium tumefaciens strain (CC), respectively. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Eight pigs (60.5 ± 3.6 kg initial BW) were surgically fitted with T-cannula in the distal ileum and allotted to a duplicated 4 × 4 Latin square design with 4 diets and 4 periods. The pigs were provided 4 corn-based diets formulated with the nontransgenic near-isoline control corn (CT), BT corn, CC corn, and commercially available nontransgenic reference corn (RF), respectively. The proximate components of the 4 corn ingredients and 4 diets were measured. The apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), and hindgut fermentation of nutrients and energy were determined. The contents of proximate components, NDF, ADF, and AA in BT corn and CC corn were comparable to those in CT and RF corn. The AID, ATTD, and hindgut fermentation of DM, CP, ether extract, ash, NDF, ADF, and GE for pigs fed the 2 transgenic corn-based diets (BT and CC) were not different with those for pigs fed the CT corn–based diet. No difference was observed in DE among the 4 dietary treatments. The AID of AA, exception of isoleucine, was not affected by the dietary treatment. The AID of isoleucine for pigs fed the BT corn–based diet and the CC corn–based diet were less (P < 0.05) than for those fed the CT corn–based diet, but there was no difference in the AID of isoleucine among the 2 transgenic corn-based diets and the RF corn–based diet. In conclusion, the mCry1Ac corn and maroACC corn have compositional and the nutritional values similar to those of nontransgenic corn.