Metabolism and Nutrition: Enzymes II

Current economic conditions necessitate that energy costs be established for nutritional and nonnutritional aspects of broiler production. Effective caloric value (ECV) enables energy cost quantification by placing caloric density equivalents upon such husbandry components as lighting program, pellet quality and bird health. Among health considerations coccidiosis mediated by the protozoan Eimeria is of concern. Metabolic costs of coccidiosis include appetite suppression and malabsorption, both of which may be impacted by dietary enzyme fortification. A 3-component 42-d factorial treatment arrangement was employed with used litter to examine the impact of cocci challenge (+ Monteban) X 2 nutritional planes (low, high) X 2 enzyme fortification levels (none, fortified). The low and high nutrition planes differed by 70 kcal/kg while enzyme effects were provided by a DSM mixture (Ronozyme AX, Roxazyme G2G, ProAct). Chicks lacking protection from Eimeria and fed the low nutrition plane exhibited the worst 42 d performance (P < 0.05) with live weight reduced 9.2%, and FCR elevated by 10.3 points. The best overall performance was achieved with high nutrition + enzymes + Monteban. However, enzyme fortification was observed to especially elevate performance of the low energy group. Just as the deleterious impact of coccidiosis appears of greater significance late in the growth curve, enzyme benefits were also enhanced. At 42 d ECV was reduced (P < 0.05) by 504 kcal with cocci challenge while enzymes elevated (P < 0.05) ECV 204 kcal averaged over cocci challenge. There is underlying value in minimizing coccidiosis consequence by fortifying rations with the aforementioned enzyme mixture. To optimize metabolizable energy utilization requires approaches that minimize energy wastage and exogenous enzymes appear to efficaciously participate in that strategy.