Use of enzymes to improve nutrient availability in poultry feedstuffs

Enzyme supplementation of cereal-based diets can significantly improve chick performance by increasing the rate of gain, efficiency of feed utilization, the apparent metabolizable energy and digestibilities of dry matter, fat and protein, with excellent improvements being obtained with diets containing rye, oats and barley. Less dramatic results are often obtained with wheat. In addition, enzyme treatment decreases the moisture content of excreta, which, together with improved dry matter digestibility, reduces the total amount of excreta produced and therefore reduces management and environmental problems. Enzyme supplementation also improves the nutritional value of lupins, and reduces the length and size of various sections of the gastrointestinal tract and the size of the pancreas of chickens. Dose-response studies with different amounts of supplemental enzymes when added to a rye-based diet demonstrated that there was a high linear correlation (r2>0.91, P < 0.05) between the concentration of enzyme when transformed into its logarithmic values and the corresponding improvements in weight gain or the feed-to-gain ratio. The log-linear model shows that for every ten-fold increase in the amount of enzyme in the diet there was a two-fold and not a ten-fold incremental improvement in chick performance. These studies suggest that there is a simple relationship between the amount of enzyme added to the diet and the resulting improvements that are obtained. Overall, enzymes when properly used can produce significant improvements in chick performance and can reduce the excretion of undigested nutrients.