Effect of the bacterial or fungal origin of exogenous xylanases supplemented to a wheat-based diet on performance of broiler chickens and nutrient digestibility of the diet

Two identical experiments were carried out to study the effects of four xylanases from bacterial or fungal origin supplemented to a wheat-based diet, on growth performance of broiler chickens and nutrient digestibilities. Experimental treatments consisted of a control basal diet containing 600 g kg-1 wheat (C), and the basal diet supplemented with 0.1 g kg-1 Grindazyme G from Aspergillus niger (G), 0.1 g kg-1 Belfeed B1100MP from Bacillus subtilis (B), 0.1 g kg-1 Roxazyme G from Trichoderma viride (R), or 0.0125 g kg-1 of a xylanase from Aspergillus aculeatus (A). Each experimental diet was given to four groups of six chickens each. Growth performance and feed conversion ratio (FCR) were recorded weekly, from 7 to 21 d of age. In the second experiment, a digestion balance trial was performed from 27 to 31 d of age to evaluate the nitrogen-corrected apparent metabolizable energy (AMEn) and the digestibilities of nitrogen, crude fat, starch and crude fibre. From 7 to 21 d of age, xylanase supplementation led to increased final body weight and daily weight gain, by 3.7 and 4.5 % (P < 0.05), respectively, without significant difference according to the xylanase origin. Xylanase supplementation significantly increased the AMEn (+2.6 %), and the digestibilities of crude fibre (+58.9 %) and nitrogen (+1.6 %). Increase in AMEn as well as in crude fat and starch digestibilities were significantly different according to the xylanase, but were not dependent on fungal or bacterial origin. In conclusion, the microbial origin of xylanases supplemented to wheat-based diets influenced neither the performance of broiler chickens nor the improvement in nutrient digestibilities