Effects of xylanase and protease on gut health and growth performance of newly hatched broiler chickens

Abstract Text: This study was to investigate the effects of supplemental xylanase and protease (BRI, Durham, NC) on gut health and growth performance of broiler chickens (288 day-old, male) fed experimental diets for 28 d. Treatments were based on 2 x 2 factorial arrangement with xylanase (0 and 15,000 XU/kg) and protease (0 and 300 U/g) as 2 factors with 9 cages/treatment and 8 birds/cage. Birds and feeders were weighed weekly for calculation of ADG, ADFI, and feed:gain (F:G). On d 7 and 28, 2 birds per pen were randomly chosen to collect blood and gut tissues for immunoglobulin G (IgG), malondialdehyde (MDA), protein carbonyl, morphology measurements. Ileal digesta were collected to determine viscosity and apparent ileal digestibility (AID). Digesta viscosity tended to decrease (P = 0.059) and decreased (P < 0.05) when both enzymes were used in wk 1 and 4, respectively, whereas it was not affected by using enzymes individually. Protease increased (P < 0.05) villus height (611 to 689 µm) in wk 4. Xylanase decreased (P < 0.05) concentrations of serum IgG (2.66 to 2.06 g/L) and ileal protein carbonyl (0.41 to 0.29 µmol/g protein) in wk 1. Protease tended to decrease (P = 0.083) serum protein carbonyl (0.78 to 0.66 µmol/L) in wk 1. Protease decreased (P < 0.05) ileal protein carbonyl (0.39 to 0.31 µmol/g protein) in wk 1, which was more effective (P < 0.05) with xylanase together. Protease decreased (P < 0.05) serum MDA (0.56 to 0.30 µmol/L) and ileal MDA (0.53 to 0.35 µmol/g protein) in wk 4. Xylanase did not affect AID, whereas protease tended to increase AID of DM (P=0.064; 74.7 to 76.5%), which was more effective (P < 0.05) with xylanase together. In wk 1, xylanase decreased (P < 0.05) F:G (1.213 to 1.173) and tended (P = 0.063) to decrease ADFI (20.1 to 19.4 g/d), whereas protease reduced (P < 0.05) ADG (17.2 to 16.0 g/d) and ADFI (20.1 to 19.4 g/d). Overall, protease increased (P < 0.05) F:G (1.504 to 1.528) whereas tended (P = 0.089) to reduce ADG (51.3 to 50.2 g/d), which was more effective (P < 0.05) with xylanase together. Mortality was not affected (P> 0.10) by the treatments. In conclusion, xylanase and protease benefited gut health by decreasing digesta viscosity, enhancing gut morphology, decreasing gut oxidative stress, and increasing nutrient digestibility, whereas these benefits were not related to growth performance.  

Keywords: broiler chickens, protease and xylanase

See more of: Nonruminant nutrition: Enzymes
See more of: Nonruminant Nutrition

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