Evaluation of xylanase form and dose in broilers fed wheat based diets.

A study was conducted to evaluate form and dose effect of a newly developed thermostable xylanase (CIBENZA® XYLAVERSE®, Novus International, Inc.) on growth performance, digesta viscosity, intestinal weight, and digesta xylanase activity of broilers fed wheat based diets. The study consisted of 6 dietary treatments: positive control, negative control with 100 kcal/kg less ME, granulated xylanase 250 and 500 U/kg, and liquid xylanase 250 and 500 U/kg. Each treatment was fed to 12 replicate battery pens of 8 Ross 308 male broilers. All diets were pelleted at 85°C and then crumbled; both xylanases were added before pelleting in the mixer. Body weight, feed intake, FCR, and mortality were determined on d 7, 15, and 21. On d 22, two birds per pen were sacrificed to collect small intestine digesta for viscosity measurement. Empty small intestine was weighed. On d 23, another 2 birds were sacrificed to collect jejunum digesta for xylanase activity determination. Data were analyzed with one way ANOVA and a P-value ≤0.05 was considered significantly different. Xylanase supplementation significantly increased 21-d body weight (3.6-6.1%) and improved 0-21 d FCR (3.5-5.4 points) with there being no difference among the xylanase treatments. Xylanase reduced digesta viscosity significantly by 23.0-34.6%. Granulated xylanase at 500 U/kg resulted in lower digesta viscosity in comparison to granulated xylanase at 250 U/kg; neither was significantly different from liquid xylanase at 250 or 500 U/kg. Xylanase decreased small intestine relative weight of broilers by 6.6-11.3% regardless of form or dose. A significant amount of xylanase was recovered in jejunum digesta in a dose dependent manner regardless of xylanase form. In summary, the study demonstrated that the newly developed xylanase was efficacious in increasing body weight, improving FCR, and reducing digesta viscosity and small intestine weight of broilers fed wheat-based diets. The newly developed xylanase was efficacious as low as 250 U/kg, and the liquid form performed as well as the granulated form in terms of both performance and gut parameters.

 

Key words: thermostable xylanase, broiler, form, dose.