Enzymes and/or combination of organic acid and essential oils supplementation in pasture‐fed free‐range laying hens increased the digestibility of nutrients and non‐starch polysaccharides

Abstract

ABSTRACT Pasture intake can be a major challenge for free‐ranging hens. This study was conducted to examine pasture digestion and to manage its negative effects. A total of 300 ISA Brown laying hens were used to investigate the effect of time on range (T) in short‐term (6 wk) and long‐term (12 wk) of 2 range types (R) (gravel vs. pasture) and dietary supplements (F) (T1 = xylanase; T2 = xylanase/beta‐glucanase/pectinase/protease; T3 = xylanase/benzoic acid/essential oils) on crude protein, crude fiber, acid detergent fiber, neutral detergent fiber, non‐starch polysaccharides (NSP), calcium and phosphorus digestibility, pH of the crop, and ileum digesta viscosity and morphology. Hens exposed to the range for 12 wk had lower (P < 0.05) digestibility of crude protein, insoluble rhamnose, ribose, and lower ileal pH compared to hens that ranged for 6 wk. Hens ranging on pasture had lower digestibility (P < 0.05) of crude protein, acid detergent fiber, neutral detergent fiber, insoluble arabinose, and insoluble xylose, but higher digestibility (P < 0.05) of insoluble mannose and glucose compared to hens that ranged on gravel. Hens fed T2 and T3 had higher digestibility (P < 0.05) of CP, acid detergent fiber, and neutral detergent fiber compared to hens fed T1. Hens fed T2 had higher digestibility (P < 0.05) of free oligosaccharide arabinose and xylose than those fed T1 or T3 diets. A significant interaction between T × R was detected for crude fiber digestibility and villus height. Digestibility of crude fiber was reduced and villus height was increased in hens ranged on pasture for 12 wk compared to 6 wk. An interaction between R × F was observed on phosphorus and soluble NSP digestibility (P < 0.05). Hens fed T2 and T3 diets had lower digestibility of phosphorus and NSP on gravel than on pasture. In conclusion, pasture consumption impaired the digestibility of nutrients. Supplementing free‐range diets with a multi‐enzyme or xylanase/benzoic acid/essential oil product reduced these negative effects and increased the ileal nutrient digestibility.