Nutritional evaluation of soybean meals varying in oligosaccharide content.

The metabolizable energy value of soybean meal for poultry is low compared to its gross energy. Several researchers believe the low metabolizable energy level is due to the low digestibility of the carbohydrate fraction. Researchers at the University of Illinois compared the digestibility and true metabolizable energy values of several genetically modified low-oligosaccharide and conventional soybean meals. The mean raffinose, stachyose and galactinol levels in the conventional soybean meal were 0.58, 3.23 and 0% respectively, compared to the genetically modified low-oligosaccharide soybean meal with levels of 0.08, 0.42 and 0.104%, respectively. Using a conventional and cecectomized rooster assay, the researchers found the metabolizable energy values corrected for nitrogen were increased by seven percent for the low-oligosaccharide meals (2,931 versus 2,739 kcal/kg dry weight). The digestibilities of raffinose and stachyose were much greater for the conventional than in the cecectomized roosters, indicating lower gut digestibility of these oligosaccharides. These studies provide additional support that soybeans can be genetically modified to improve the nutritional value to soybean meal. Bioengineering soybeans with traits for specific end uses may be economically possible in the future.

Parson, C.M., Y. Zhang and M. Araba. 2000. Nutritional evaluation of soybean meals varying in oligosaccharide content. Poultry Sci. 79:1127-1131.