The Interaction Mechanism Between Exogenous And Endogenous Enzymes In Broiler Diet

Because of feed resources shortage and low digestibility of nutrients, it is necessary to add enzymes to improve the feed utilization. In practice, the supplementation of enzymes is often blindly carried out in the process of poultry production without considering the collaborative and antagonistic relations among enzymes, without considering matching ability between enzymes and substrate. Four experiments were conducted to investigate nutritive improvement of polysaccharide enzyme on the broiler diet with DDGS, and interaction among these enzymes, to provide theoretical basis for reasonable and scientific application of enzymes.Trial 1. The effect of cellulase, hemicellulase, and pectinase on nutritive digestibility of the broiler diet with DDGS. Two-stage of pepsin-pancreatin method was used with the broiler diet containning 15% DDGS as substrate. Three 4×4 factorial arrangements were conducted with cellulase and hemicellulase, cellulase and pectinase, or hemicellulase and pectinase as main effects. Each treatment consisted of 4 replicates. The digestibility of air dry matter and crude protein, the release of reducing sugar was examined. The results showed that cellulase, pectinase and hemicellulase significantly increased the release of reducing sugar (P<0.01), and there was a significant synergy between them (P<0.01). The digestibility of air dry matter and CP was significantly improved by cellulase and pectinase (P<0.05), and combination of them significantly improved the air dry matter digestibility (P<0.01), but no effect on the CP digestibility. air dry matter digestibility was significantly decreased by hemicellulase (P<0.01). The interaction between hemicellulase and pectinase significantly improve the CP digestibility (P<0.01), but interaction between hemicellulase and cellulase did not affect CP digestibility.Trial 2. The interaction among hemicellulase, pancretin and pepsin. Two-stage of pepsin-pancreatin method was used with the broiler diet containning 15% DDGS as substrate. A 2×2×2 factorial arrangements was used with 2 pepsin levels (0, 300 U), 2 pancretin levels (0, 3.7 mg), and 2 hemicellulase levels (0, 300 U) as main effects. Each treatment consisted of 4 replicates. The air dry matter digestibility and the release of reducing sugar were examined. The results showed that pepsin and pancretin significantly increased the release of reducing sugar (P<0.01). There was a significant synergy between them for the air dry matter digestibility (P<0.01), but no effect on the release of reducing sugar (P=0.220). Hemicellulase significantly improved the release of reducing sugar (P<0.01), but did not affect the air dry matter digestibility. Interaction between hemicellulas and pancretin significantly decreased the air dry matter digestibility (P<0.01).Trial 3. The antagonism between hemicellulase and pancretin. Two-stage of pepsin-pancreatin method was used with the broiler diet containning 15% DDGS as substrate. Two groups of 3×3 total factorial arrangements were conducted with hemicellulase (0, 150 U, 300 U) and lipase (0, 1500 U, 3000 U), or amylase (0, 100μL, 200μL). Each group consisted of 9 treatments with 4 replicates. The results showed that hemicellulase, lipase and amylase significantly increased the release of reducing sugar (P<0.01). There was a significant synergy between hemicellulase and lipase or amylase (P<0.01) on reducing sugar. Lipase and amylase improved the air dry matter digestibility (P<0.01), and there was a significant antagonism between them and hemicellulase for the air dry matter digestibility (P<0.01).Trial 4. The interaction among hemicellulase, lipase and amylase. Two-stage of pepsin-pancreatin method was used with the broiler diet containning 15% DDGS as substrate. Two groups of 2×2 total factorial arrangements were designed with hemicellulase (0, 300 U) and lipase (0, 1500 U), or amylase (0, 200μL). Each group consisted of 4 treatments with 4 replicates. The results showed that hemicellulase, lipase and amylase significantly increased the release of reducing sugar (P<0.01). There was a significant synergy between them and hemicellulase (P<0.01) on reducing sugars, Lipase and amylase improved the air dry matter digestibility (P<0.01), but there was a significant antagonism between them and hemicellulase for the air dry matter digestibility (P<0.01).Based on the results of the present research, we concluded that cellulase, hemicellulase and pectinase cooperated to degrade the NSP of the diet with DDGS; there was a significant synergy between hemicellulase and lipase, or amylase for the release of reducing sugar, but an antagonism for the air dry matter digestibility, the specific mechanism is under investigation.