Nutritive value, mycotoxin contamination and in vitro rumen fermentation of normal and genetically modified corn (cry1A(b)) grown in northern Italy

An assessment was made on the effect of inserting the cry1A(b) (Bt) gene of Bacillus thuringiensis into the genoma of two corn hybrids (the newly-deve loped hybrid from Cargill Semences identified as CR and the traditional B73 xMo17) on the analytical composition, the in vitro rumen degradability and the mycotoxin contamination of the plant. Transgenicity changed the plant c hemical composition as a function of the recipient genotype: starch was inc reased in the CR-Bt(+) plant (70.4% vs 73.3%; P < 0.10) whereas higher lign in content (6.3% vs 7.3%; P < 0.05), lower protein 7.7% vs 7.1%; (P < 0.10) and soluble nitrogen (34.8% vs 26.9%; P < 0.10) contents a ere observed fo r the B73xMo17-Bt(+) plants. When not considering the hybrid pedigree there was a tendency (p < 0.1) toward a lower protein content in the Bt(+) corn seeds (9.2 re 8.2%) and a higher sugar content in stalk and leaves (2.9% vs 5.7%). The stover degradation increased in the CR-Bt(+) variety, probably as the consequence of the higher content of lower structured carbohydrates. Transgenic plants had less ergosterol and fumonisin content than standard corn, suggesting a reduced susceptibility to mould attack.