Analysis Of The Apparent Nutrient Digestibility,Immune Function And Intestinal Microflora In Broilers With Different Performance

The study aimed to find the reasons of different growth performances of AA broilers under the same environmental conditions feeding,management factors.A total of 200 one day old broilers were fed to 35 days,The broilers(n=120)were divided into four groups,group A(1.5kg~1.7kg),groupB(1.30~1.49kg),group C(1.00~1.29kg)and group D(0.80~0.99kg).Each group had five replicates with six broilers.On 42 days,two broilers per treatment were selected by similar body weight and weighed following 12 h fast.Growth performance,apparent metabolic rate of nutrients,blood markers and bacterial flora were checked on day 42.Part 1 Different production performance of 35~42 days.The results showed that feed/gain ratio(F:G),average daily gain(ADG)and average daily feed intake(ADFI)of group A,group B and group C were significantly higher than those in group D(P<0.05).Part 2 Apparent digestibility of different growth performance.From group D to group A,the digestibility of crude protein was significantly increasing(P<0.05).Part 3 The blood biochemical index and immune function of different growth performance.Triglyceride concentration of group A was significantly higher than group B,group C and group D(P<0.05);Thymus of group A was significantly higher than group B,group C and group D(P<0.05);Thymus of group B was significantly higher than group C and group D(P<0.05).Spleen of group A was significantly lower than group B,group C,group D(P<0.05).Bursa of group A and group B was significantly higher than group C and group D(P<0.05).IgA concertration of Group A was significantly higher than group B,group C,group D(P<0.05);IgG concertration of Group A was significantly higher than group B,group C,group D(P<0.05).Howevev,Newcastle immune antibody titer of group A was significantly lower than that in group B,group C,group D(P<0.05).Part 4 Microbial bacteria of different growth performance.The percentage of Firmicutes in total microbiota populationwas was 43.43%,36.45%,39.34%,and 35.66% of group A,group B,group C and group D respectively;The percentage of Tenericutes in total microbiota populationwas was 3.41%,2.42%,1.73%,and 1.41% of group A,group B,group C and group D respectively;The percentage of Proteobacteria in total microbiota population was 4.34%,2.62%,2.29%,1.98%of group A,group B,group C and group D r espectively;The percentage of Synergistetes in total microbiota population was 0.01%,0.32%,0.30% and 0.50% of group A,group B,group C and group D respectively;The percen tage of Fusobacteria in total microbiota population was 0.00%,0.00%,0.00%,0.14% of g roup A,group B,group C and group D respectively;The percentage of Verrucomicrobia in total microbiota populationwas was 4.15% of group D respectively.On genus level,the percentage of Uncultured in total microbiota population was 31.03%,21.49%,6.15%,19.43% of group A,group B,group C and group D respectively;The percentage of Unk nown in total microbiota population was10.58%,6.90%,7.22%,8.83%of group A,group B,group C and group D respectively;The percentage of others in total microbiota populati on was 7.13%,8.90%,5.55%,8.88% of group A,group B,group C and group D respecti vely;The percentage of Akkermansia in total microbiota populationwas was 0.01%,1.04%,1.23%,4.15% of group A,group B,group C and group D respectively;The percentage o f Bairnesiella in total microbiota populationwas was 4.80%,10.58%,13.37%,19.71% of group A,group B,group C and group D respectively.Firmicutes,Tenericutes,Proteobac teria,Uncultured,Unknown and others would increasebroilersgrowth performance.Synergiste tes,Fusobacteria,Verrucomicrobia,Akkermansia,Bairnesiella would restrain broilers growth performance.Conclusion: Decreased feed intake,production performance decrease and immunity of intestinal and harmful bacteria in the proportion will inhibit broilers.