Evaluation of Exogenous Enzymes Targeting Non-starch Polysaccharides in Reduced Energy Diets on Broiler Growth Performance and Processing Parameters
Klein, Joseph Thomas
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Multiple experiments were conducted to investigate the inclusion of a cocktail NSPase and ?-mannanase, separately and in combination, in reduced energy diets on broiler growth performance and processing yield. Each experiment contained a positive control (PC), negative control (NC) diet (-132 kcal/kg AME), and the inclusion of enzymes in the NC to evaluate enzyme effectiveness. The reduction in energy negatively impacted performance and processing parameters in all experiments. The inclusion of NSPase negated the negative effects of energy reduction in experiment 1. Experiment 2 evaluated increased pelleting temperature on NSPase activity. Body weight (BW) was increased (P<0.05) with the inclusion of NSPase pelleted at 80, 85, and 90 C throughout the experiment compared to NC; however, the treatment pelleted at 80 C outperformed the other NSPase pelleted treatments. The inclusion of NSPase pelleted at 80 C reduced (P<0.05) feed conversion ratio (FCR) compared to the NC throughout the experiment. At the conclusion of the trial, NSPase inclusion pelleted at 85 and 90 C yielded FCR similar to PC. The experimental design of experiment 3 and 4 included five dietary treatments including a PC, NC, NC supplemented with ?-mannanase, NSPase, and ?-mannanase/NSPase. Performance parameters were evaluated on d 14, 28, 42, and 47 and a subset of broilers were processed on day 48. Increases (P<0.05) in BW were observed with the inclusion of NSPase and ?-mannanase/ NSPase on day 14 and with all treatment groups on day 28. An additive effect was observed with reduced FCR through day 28 with the combination of ?-mannanase/ NSPase. In experiment 4, performance was evaluated on days 14, 27, 35, and 41 and carcass yields determined on day 42. Increases in day 14 BW were observed with the inclusion of the NSPase alone and ?-mannanase/NSPase to reach a similar weight as the PC. Inclusion of ?-mannanase/NSPase increased (P<0.05) BW compared to the NC. Inclusion of the NSPase reduced (P<0.05) cumulative FCR through 41 days of age. Inclusion of ?-mannanase/NSPase resulted in reduced (P<0.05) FCR in the finisher phase and cumulatively throughout the trial to levels of the PC. The combination of ?-mannanase/NSPase did increase (P<0.05) WOG weight similar to observations in BW. These data confirm that enzyme supplementation in low energy diets improve performance and indicate that additive effects of a combination of enzymes could potentially be a cost saving strategy for producers.