Study Of The Effect Of Xylanase On Non-Starch Polysaccharides Degrading Law In Wheat-Based Diet And The Intestinal Histology In Broiler Chickens

To improve the wheat application in feed industry and develop the uncommon feedstuff, both in vivo and in vitro trials were conducted to study the effect of wheat-based diet supplemented with xylanase on the digestibility of non-starch polysaccharides and the intestinal histology in broiler chickens. The objective of this study was to investigate the action mode of xylanase in the gastrointestinal tract of broiler chickens.The results of the digestibility of non-starch polysaccharides (NSP) in the digestive tracts and feces of broiler chicken showed that xylanase could significantly improve the digestibility of soluble NSP (SNSP) and insoluble NSP (INSP) in the feces, and the main action sites to SNSP were crop, jejunum and ileum, to INSP were crop and gizzard. The digestibility of soluble NSP in crop, jejunum, ileum and feces were higher(P <0.05), while the values in gizzard, duodenum and rectum (P >0.05) was higher in all the groups (0.02% I,0.05% I , 0.02% II and 0.05% II) supplemented with xylanase than that of the group without exoenzyme. Besides, compared with the group fed diet with no xylanase, the digestibility of insoluble NSP in crop, gizzard and feces was higher (P <0.05). In addition, the digestibility of INSP in duodenum and ileum had been improved (P>0.05) to different degrees.The results of the ileal and fecal apparent digestibility of nutrients and NSP and change of the small intestinal histology in broiler chickens showed that xylanase significantly improved the ileal and fecal apparent digestibility of nutrients, improved the histology of duodenum and ileum, but negative effects was observed of jejunum. 1) The ileal and fecal apparent digestibility of starch (P <0.05), ileal apparent digestibility of SNSP and INSP (P <0.01) as well as the fecal apparent digestibility of SNSP (P <0.05) were improved in the broilers fed diet with 0.1%xylanase. 2) The duodenum crypt depth and villus height were increased (P>0.05) and the intestinal wall thickness was decreased (P<0.01). Furthermore, the ileal crypt depth and villus height were significantly increased (P<0.01), but jejunal villus height and V/C(villus height/crypt depth) was decreased to different degree in broilers fed diet with 0.03% and0.1%xylanase.The results of the digestibility of the wheat nutrients and non-starch polysaccharides in vitro showed that xylanase improved the digestibility of SNSP and INSP (P<0.05), but had no effect on the digestibility of DM (dry matter), ash and starch (P>0.05). The SNSP digestibility was higher than that of INSP whether or not the xylanase was supplemented. The digestibility of DM, ash and starch improved along with the reacting time(2h, 4h, 6h and 8h) prolonged. There was no interaction (P >0.05) between xylanase dose and reacting time to all the parameters except the digestibility of INSP.