Effects of a carbohydrase complex added in different inclusion rates in feeds for broilers on growth performance, digesta viscosity and foot pad health.

Foot pad dermatitis (FPD) is a widespread disease in poultry and important for economic and animal welfare reasons. It is well recognized that using non-starch polysaccharide (NSP)-degrading enzymes can affect excreta/litter quality (not only in terms of moisture content but also regarding water evaporation) at high stocking densities and might help to prevent FPD and further negative effects of NSP. This study aimed to evaluate effects of a carbohydrase complex (CC) in different dietary inclusion rates on performance, digesta viscosity and foot pad health in broilers from 9 to 37 days of life. In total, 240 broilers were divided into 12 floor pens of 20 birds and received one of four different experimental diets. The four wheat- and soyabean meal-based diets only differed in the inclusion rate of CC: 0%, 50%, 100% and 500% of the recommended dose of CC (Endo-1,4-ß-xylanase and Endo-1,3(4)-ß-glucanase; 50 g/t). The addition of CC led to a significant decrease of digesta viscosity in the proximal small intestine, a tendency of improved feed conversion ratio, and significantly favoured FPD-scores (Treatment 2). At the higher tested inclusion rate of CC (500% of recommended dose), the FPD score was worser than in the treatments with 50% and 100% of the recommended enzyme dosage. No improvements among treatments were observed in terms of body weight and dry matter content of excreta and litter at the end of trial. The low positive effects on foot pad health in this study were presumably associated with the low NSP content in the experimental diets (soluble arabinoxylans: 7.38 g/kg as fed). In conclusion, the addition of the evaluated CC reduced digesta viscosity. An improvement of foot pad health could only be seen in the treatment with 50% of the recommended enzyme dosage in the diet.