Endogenous enzyme activities and tibia bone development of broiler chickens fed wheat-based diets supplemented with xylanase, β-glucanase and phytase

OBJECTIVE: This study assessed the effect of different levels of xylanase, β-glucanase and phytase on intestinal enzyme activities and tibia bone development in broiler chickens fed wheat-based diets. METHODS: Twelve experimental diets were formulated using a 3×2×2 factorial design (three doses of phytase and two doses of both xylanase and β-glucanase) and offered to 648 day-old Ross 308 male chicks having 6 replicates groups with 9 birds per replicate and lasted for 35 days. RESULTS: An interaction between the enzymes products improved (p<0.01) the activity of chymotrypsin. Protein content at d 10 was highest (p<0.001) with addition of phytase while general proteolytic activity (GPA) (p<0.02) and lipase activity (p<0.001) were decreased. At d 24, there were improvements in protein content (p<0.01) and lipase (p<0.04) with supplementation of superdose phytase. Addition of superdose phytase decreased in chymotrypsin (p<0.02), trypsin (p<0.01) and GPA (p<0.001). The optimum dose of xylanase decreased the chymotrypsin activity (p = 0.05), while the GPA (p<0.001) was increased with the optimum level of β-glucanase. Superdose phytase supplementation at d 10 improved maltase (p = 0.05), sucrase (p<0.001) and alkaline phosphatase (p<0.001) activities in the jejunum while aminopeptidase activity was highest (p<0.005) with the low level of phytase. Protein content of jejunum mucosa was bigger (p<0.001) in birds fed superdose phytase while maltase activity (p<0.001) at d 24 was reduced by this treatment. Sucrase (p<0.04) and aminopeptidase activities (p<0.001) improved when diets supplemented with low levels of phytase. Tibia bone breaking strength was highest (p<0.04) with addition of low level of superdose phytase or optimum level of β-glucanase. Bone dry matter content decreased (p<0.04) when diets supplemented with phytase. CONCLUSION: From the results obtained in this study, supplementation of superdose phytase was the most effective, however, the cost-benefit analysis of the use of such a dose needs to be evaluated.