Effects Of Superfine Xylooligosaccharides On Growth Performance, Antioxidant And Immunity Function Of Broiler Chickens

This study was conducted to investigate the effects of superfine xylooligosaccharide (XOS) on AA broilers. The paper included three experiments:Trail1was conducted to study the effects of different dosages of superfine XOS on the growth performance of broilers.240one-day-old Arbor Acres broilers with the same average weight were randomly assigned into5treatments with6replicates(8birds per replicate). The birds were fed with basal diet (control group) and treatment diets supplemented with common XOS(100mg/kg), and different levels of superfine XOS (50mg/kg,75mg/kg and100mg/kg, respectively). The results showed that:In the starter period (1～21d), there were no significant difference among all groups on growth performance (.P>0.05). In the grower period (22～42d), experimental groups had an improved ADG and body weight of42d compared with the control group (P>0.05), while ADFI increased significantly by8.46%(P<0.05)、4.94%(P>0.05)、5.97%(P>0.05) and5.55%(P>0.05). The broilers fed with diets supplemented with100mg/kg common XOS and75mg/kg superfine grinded XOS had a decreased feed/gain ratio (F/G) compared with the control group(P>0.05). In the whole period (1～42d), broilers fed with the diets supplemented with100mg/kg common XOS and75mg/kg superfine XOS had a decreased feed/gain ratio (F/G) compared with control group (P>0.05).Trial2was conducted to study the effects of superfine XOS on intestinal pH and morphology of AA broilers. The materials and methods were the same as those in Trial1. The results showed that XOS decreased21-d muscle stomach pH,21-d ileum pH,42-d jejunum pH and42-d ileum pH slightly. In addition, at21d, jejunm pHs in the100mg/kg common XOS group and the75mg/kg superfine XOS group decreased (P<0.05), and were significantly lower than the50mg/kg superfine XOS group (P<0.05); XOS had no significant effect on duodenal gut morphology (P>0.05), but reduced the jejunum crypt depth and increased the jejunum V/C value. At21d, jejunum V/C values in the100mg/kg common XOS group and the75mg/kg superfine XOS group increased by19.26%and 24.22%(P<0.05). At42d, compared with the control group, villi lengths of the experimental groups were increased by6.45%,6.19%,7.26%, and5.75%,respectively (P<0.05), the ileum V/C values increased slightly, but muscle thicknesses thereof had no significant changes (P>0.05).Trial3was conducted to investigate the effects of superfine XOS on the antioxidant and immune function of broilers. The materials and methods were the same as those in Trial1. The results showed that the T-AOC of serum in experiment groups were higher than control group by24.37%,35.70%,46.88%and45.72%, respectively, in21d (P<0.05), while the MDA of serum in groups added with75mg/kg superfine grinded XOS was decreased by35.46%(P<0.05). There were no significantly effect of XOS on antioxidant function of mucosa, but75mg/kg superfine XOS could reduce the MDA of mucosa significantly compared with100mg/kg superfine XOS in the diet (P<0.05). Diet supplemented with100mg/kg common XOS and50mg/kg superfine XOS had no significant effect on the immune organ index and serum immune indicators (P>0.05);75mg/kg superfine XOS improved42-d bursal index highly significantly (P<0.01),21-d serum lysozyme content and newcastle disease antibody titers significantly (P<0.05);100mg/kg superfine XOS made the42-d bursal index decrease significantly (P<0.01), but had no significant effect on newcastle disease antibody titers and lysozyme (P>0.05). XOS had no significant effect on the number of goblet cells of the duodenum and jejunum (P>0.05), but100mg/kg common XOS or75mg/kg superfine XOS could increase the number of21-d ileum goblet cells (P<0.05); In addition, compared with the control group, at42d, intestinal mucosal SIgA in the experimental groups were increased by4.77%(P>0.05),3.81%(P>0.05),14.64%(P<0.05) and11.83%(P>0.05), respectively.In conclusion, under the conditions of this experiment,75mg/kg superfine XOS had best effects on the growth performance, antioxidant and immune functions of broilers.