The Relationship between Dietary Calcium and the Activity of Digestive Enzymes in Broiler Chicks

Activity of digestive enzymes and certain biochemical parameters in the native and freeze-dried duodenal digesta and freeze-dried ileal digesta were studied in a chronic experiment in broiler chicks with chronic duodenal or ileal fistulae fed with various calcium doses. The results show that the amylase activity after freeze-drying in the control group increases 5.7-fold, the lipase activity 11.6-fold, and the activity of total proteases 8.2-fold. For alkaline phosphatase, the increase in activity is 15.9-fold. The calcium level after freeze drying increases 11.4-fold and the phosphorus content 17.7-fold. The cholesterol level after drying is 4.8-fold higher. As calcium levels in the diet of broilers decrease from 0.9 to 0.8%, the activity of alkaline phosphatase in the duodenal digesta increases by 35.1% compared with the control group ( p ≤ 0.05). Therefore, freeze drying changes the enzymatic activity and the content of minerals in the chyme unevenly. When the level of calcium in the diet changes, the activity of amylase, lipase, proteases, alkaline phosphatase, calcium, phosphorus, and cholesterol in the ileal content is shown to adapt, which can be used to diagnose intestinal health of poultry in new test systems.