NUTRITIVE VALUE OF ENZYME PRE-TREATED CANOLA MEAL

摘要

Canola protein is of high biological value but the use of the meal in diets for young rapidly growing animals is limited by the less than optimum availability of energy and amino acids. Experiments were conducted to explore the potential for improving the nutritive value of canola meal by the use of dietary enzymes and, in particular, the pretreatment of canola seed with enzymes during the crushing process was investigated. A number of carbohydrase-like (i.e., β-galactosidase, pectinase, cellulase) and phytase enzymes were evaluated in vitro (80% moisture content) for their ability to hydrolyse oligosaccharides and phytate and to depolymerize the non-starch polysaccharides (NSP) of canola meal. Based on the in vitro results it was shown that there was an additive effect of enzyme blends over single enzymes on NSP and phytate hydrolysis. Three selected enzyme blends were used to pretreat canola seed and the enzyme pretreated canola meal (16%―20% moisture) did not show any reduction in NSP or phytate. However, when the pretreated canola meals were fed (30% of the diet) to 4-day-old broiler chickens for a 2-week period, improvements in growth performance relative to a control diet were noted. Compared to the control diet, enzyme pretreated canola meals significantly increased body weight gain and improved feed to gain ration (one blend). Three enzyme blends resulted in improved ideal protein digestibility and phytate digestibility while only two blends showed an improvement in apparent metabolizable energy. The study indicated that there is potential for improvement of the quality of canola meal by enzyme pretreatment, particularly with the use of multi-enzyme blends. However, the relatively low moisture content in desolventized canola meal would appear to limit the effectiveness of the pretreatment of canola seed during the crushing process. Further research is needed to realize optimum effects of adding enzymes in the crushing of canola seed to produce a meal of improved nutritive value.