The effect of enzymes on digestion

Exogenous enzymes often markedly influence ingredient and diet digestibility. In many cases the digestive capacity of the bird is overwhelmed, which is certainly the case in younger birds for whom output of endogenous enzymes may be deficient and high intestinal viscosity can compromise the digestive efficiency of the gastrointestinal tract. Augmentation of the host's own enzyme systems and hydrolysis of viscous polymers can certainly improve nutrient digestibility in younger birds. Specific antinutrients such as phytate can be catabolized from an antinutrient to a nutrient (i.e. phosphorus), providing a benefit not only in phosphorus digestion but also in removing the substrate's ability to chelate minerals and complex digestive enzymes. Enzymatic destruction of lectins and trypsin inhibitors reduces endogenous losses, thereby improving apparent digestibilities, and reduces the total energy expenditure in digestion, further benefiting performance. Alteration of the fermentation profiles in the bird can significantly benefit performance by more effective partitioning of ileal nutrients between the bird and resident flora, provision of nutrients in the caeca from fiber digestion, and by reduction in immunological challenge.