September 21/Asian - Australasian Journal of Animal Sciences -- The soybean is the most widely used vegetable protein source for monogastric animals and is the most prevalent legume/oil seed crop in the world (FAO, 2008). However, soybeans contain nearly as much carbohydrates as protein, yet the nutritional and/or anti-nutritional activities of these carbohydrates in animal feed are quite often ignored.
Poor growth performance has been observed when broilers were fed diets containing soybean meal (SBM) as the sole dietary protein source(Irish and Balnave, 1993). It was observed that the poor growth of broilers fed SBM as the sole protein source was more pronounced with meals processed in Australia compared with the meals processed in the United States. This response was assumed to be related to the higher fiber content of Australian processed meals (Irish and Balnave, 1993). The poor growth performance could not be explained by the digestibility or the amount of essential amino acids, or the process of heat treatment of the SBM tested. A significant relationship was observed between the water-soluble xylose content of the soybean meals and the improvement inweight gain obtained when sunflower meal replaced some of the soybean meal. Measurement of free sugars in the supernatant of the digesta in the ileum indicated that the stachyose derived from the oligosaccharides of SBM appeared to exert an anti-nutritive effect when SBM waspresent at high concentrations as the sole protein source in broilerdiets (Irish and Balnave, 1993).