The effects of enzyme supplementation on performance and digestive parameters of broilers fed corn-soybean diets

The study was performed to evaluate the effects of enzyme supplementation on performance and digestive parameters of broilers fed corn-soybean diets from 1 to 21 d of age. A total of 480 one-day-old Cobb broilers were allocated to 1 of 4 treatments, with 6 replicate pens per treatment and 20 birds per pen. The experiment consisted of a 2 × 2 factorial arrangement of treatments with 2 dietary ME levels (high ME, energy 1, 12.13 MJ/kg or low ME, energy 2, 11.92 MJ/kg) and 2 levels of supplemental enzyme (including xylanase, 1,800 IU/g, β-glucanase, 500 IU/g, and α-amylase, 800 U/g; 0 or 0.1% of diet). Enzyme supplementation had no effect on average daily weight gain, feed intake, and feed:gain. However, enzyme supplementation decreased the relative weight of the pancreas (d 7 and 21) in broilers fed the high ME diet. Low dietary ME level increased pancreatic lipase (d 7, P = 0.015), trypsin (d 14, P = 0.01; d 21, P = 0.014), amylase (d 21, P = 0.027), and pepsin (d 7, P = 0.001; d 21, P = 0.042) activity, but reduced pancreatic lipase (d 14, P = 0.03; d 21, P = 0.004) and amylase (d 14, P = 0.027) activity. Enzyme supplementation resulted in an increase in pancreatic amylase (d 7, P = 0.023), trypsin (d 7, P = 0.02; d 21, P = 0.004), lipase (d 21, P = 0.001), pepsin (d 7, P = 0.001; d 14, P = 0.004; d 21, P = 0.001), and maltase (d 14, P = 0.011, in ileum) activity. Moreover, broilers fed low dietary ME and enzyme supplementation diets had an increase in pancreatic lipase (d 21, P = 0.001) and pepsin (d 7, P = 0.001) activity. Low ME diets reduced jejunum villus height and jejunum and ileum crypt depth (d 7, 21). However, enzyme supplementation, especially enzyme supplementation in low ME diets, increased jejunum and ileum villus height and villus surface area. This suggested enzyme supplemented with low ME diet might be more effective to improve the activity of digestive enzymes and the absorptive capacity of the small intestine.