Effects of β-mannanase on Egg Production Performance, Egg Quality, Intestinal Microbiota, Viscosity, and Ammonia Concentration in Laying Hens

Two experiments were conducted to evaluate the effects of beta-mannanase on egg production performance, egg quality, intestinal microbiota, viscosity, and ammonia concentration in laying hens. In Exp. 1, two hundred and seventy 30-wk-old Hy-Line Brown laying hens were assigned to 6 diets arranged in a 3 x 2 factorial of three levels of MEn and CP [(a corn-soybean meal based diet (HEHP), a diet containing 50 kcal of MEn/kg and 1.0% less energy and CP than the HEHP (MEMP), and a diet containing 80 kcal of MEn/kg and 1.5% less energy and CP than HEHP (LELP)], and beta-mannanase supplementation (0 or 0.04%). In Exp. 2, A total of two hundred and sixteen62-wk-old Hy-Line Brown laying hens were assigned to 6 dietary treatments in a 3 x 2 factorial arrangement. In Exp. 1, beta-mannanase supplementation increased egg production rate in hens fed LELP diet, but not in those fed HEHP or MEMP diet (interaction, p<0.01), and the interaction was significant (p<0.01) for egg mass. beta-mannanase supplementation decreased (p<0.05) ammonia concentration. In Exp. 2, the supplementation of beta-mannanase increased egg production rate and egg mass in hens fed LELP diet, whereas no differences were found in those fed HEHP or MELP diet (interaction, p<0.01). The supplementation of beta-mannanase in a lower energy and protein diet resulted in similar production performance when compared to high-energy and high-protein diet during early and late stages of egg production.