Application Study Of Different Levels Of Xylooligosaccharides And Antibiotics In Broilers Diets

1008 one-day AA broilers were randomly allocated to 6 treatments with 8 replicates and 21 birds for each. The birds were fed with basal diet (control group) and five treatment diets supplemented with antibiotics (zinc bacitracin 16.7mg · kg and colistin sulfate 3.3mg· kg^-1, control), antibiotics(20 mg·kg^-1)+xylooligosaccharides (100 mg · kg^{-19 or 150 mg· kg-1, XOS} and antibiotics(15 mg · kg^-1)+XOS(100 mg ·kg^-1 or 150 mg·kg^-1) to study the effects of XOS and antibiotics on the performance, intestinal microflora and antioxidant activity of broilers.Performance of broilers results showed that compared with control group, experimental diets increased body weight gain (BWG) by -2.5%-1.9% in the starter stage (0-21 days), 1.5%-16.2% in the finishing stage (22-42 days), 1.0%-10.3% in the whole stage (0-42 days), respectively. Basal diet supplemented with antibiotics+0.015%XOS apparently improved BWG in both finishing stage and whole stage (p<0.05). The improvement of supplementing antibiotics+0.015%XOS and 75%antibiotics+0.015%XOS is nearly 2 and 3 fold (p>0.05), individually, when comparing with 75%antibiotics+0.01%XOS. Supplementing antibiotics+0.015%XOS enhanced feed intake in the starter and finishing stage. Experimental diets improved feed conversion ratio (FCR) by 0.5%, 1.5%, 5.4%(p<0.05), -1.5% and 1.5%. The diet supplemented with antibiotics+0.015%XOS had better amelioration in BWG and FCR compared with other groups.Observations from the number of bacteria in the jejunum indicated that in the starter stage, supplementing antibiotics, antibiotics+0.01%XOS(p<0.05),antibiotics+0.015%XOS(p<0.05) and 75%antibiotics+0.015%XOS increased the number of E.coli. and the number of lactic acid bacteria in each treatment increased by 4.3%, 8.0%, 8.8%, 4.5% and 10.6% without significantly, when comparing with control diet. And in the finishing stage, respectively, the number of E.coli. of experimental groups deceased by 19.5%, 6.9%, 2.1%, 9.0%, 18.5% and the number of lactic acid bacteria increased by 2.2%, 6.4%, 12.9%, 4.3% and 3.8% without any significance.