Effects Of Different Antibiotic Substitutes On Growth Performance,Antioxidant Index And Intestinal Health Of Broilers

The aim of this study was to investigate the effects of gradient addition of AP,HTA and GOD on performance,antioxidant index and intestinal health of broilers.Through the analysis of production performance,slaughter performance,serum biochemical and antioxidant index,intestinal flora and other data,it provides a theoretical basis for the application of AP,HTA and GOD in non-antibiotic culture of broilers.In this experiment,the control group was fed on a basic diet,and the experimental group was gradient supplemented with AP(200 g/t,300 g/t,500 g/t),HTA(200 g/t,400 g/t,600 g/t),GOD(100 g/t,200 g/t,400 g/t)and antibiotics(150 g/t).A total of 440 AA broilers(1 day old)were randomly assigned to eleven groups with five replicates of eight broilers in each replicate and each replicate is one unit.The test period was 42 days,during this period,3-layer cage feeding,full-day-old light,free access to food and drinking water.The results showed as follows:(1)There was no significant difference in average daily feed intake(ADFI),average daily gain(ADG),and the feed/gain(F/G)between the treatment groups at 42 days of age(P > 0.05).(2)The slaughter rates in the AP groups(200 g/t,300g/t,500 g/t),the HTA groups(400 g/t,600 g/t),the GOD groups(100 g/t,200 g/t,400 g/t),and the antibiotic group(150 g/t)was significantly better than that in the control group(P <0.01).The whole net carcass rate in the AP group(500 g/t),the HTA groups(400 g/t,600g/t),and the GOD group(400 g/t),was significantly better than that in the control group(P< 0.05).There was no significant difference between the treatment groups in the indicators of half-clean chamber rate,chest muscle rate and leg muscle rate(P > 0.05).(3)The HTA group(600 g/t)and GOD group(400 g/t)were significantly higher in the spleen index than the control group(P < 0.05).There was no significant difference in bursa index and thymus index between the treatment groups and the control group(P > 0.05).(4)There was no significant difference in AST,ALP,TP,ALB,UREA,CHOL between the treatment groups and the control group in serum biochemistry for 21 days(P > 0.05).The 42 days' serum ALP content in the antibacterial peptide group(200 g/t),the HTA group(200 g/t)and the GOD groups(100 g/t,200 g/t)was significant lower than that in the control group(P < 0.05).The serum TP in the antibacterial peptide group(200 g/t)and the HTA groups(200 g/t,400g/t)was significant better than that in the control group(P < 0.05),there was no significantdifference in AST,ALB,UREA,CHOL in other treatment groups(P > 0.05).(5)There was no significant difference in serum MDA content at 21 days and 42 days.At the age of 21 days,the SOD activity in the AP groups(300 g/t,500 g/t),the HTA groups(200 g/t,400 g/t,600 g/t),the GOD groups(200 g/t,400 g/t)and the antibiotic group was significantly better than that in the control group(P < 0.01).The GSH activity in the AP groups(200 g/t,300g/t,500 g/t),the HTA groups(400 g/t,600 g/t)and the GOD groups(400 g/t)was significantly better than that in the control group(P < 0.01).At the age of 42 days,the serum SOD activity in the AP group(500 g/t)and the GOD group(400 g/t)was significantly better than that in the control group(P < 0.05).The GSH activity in the AP group(500 g/t),the HTA group(600 g/t)and the GOD group(400 g/t)was significantly better than that in the control group(P < 0.05).(6)The liver SOD activity in the AP groups(300 g/t,500 g/t),the HTA groups(200 g/t,400 g/t,600 g/t),the GOD group(400 g/t)was significantly better than that in the control group(P < 0.01).The liver MDA content in the HTA group(600 g/t)was significantly lower than that in the control group(P < 0.01).The liver GSH activity in AP group(500 g/t)and the GOD groups(200 g/t,400 g/t)was significantly better than that in the control group(P < 0.01).(7)There was no significant difference in the pH value between the duodenum and the cecum in each treatment group(P > 0.05).(8): The trypsin activity in the AP groups(200 g/t,300 g/t,500 g/t)and the GOD group(400 g/t)was significantly better than that in the control group(P < 0.05).The lipase activity in the AP group(500 g/t),the HTA group(600 g/t)and the GOD group(400 g/t)were significantly better than that in the control group(P < 0.01).The amylase activity in the AP group(500 g/t),the HTA groups(200 g/t,400 g/t,600 g/t)and the GOD group(400g/t)was significantly better than that in the control group(P < 0.01).(9)The count of lactobacillus caecum In the AP group(300 g/t,500 g/t),the HTA group(600 g/t),and the GOD group(400 g/t)was significantly better than that in the control group(P < 0.05).There was no significant difference in the quantity of aerobic bacteria and Escherichia coli in each treatment group(P > 0.05).In conclusion,adding a certain amount of antimicrobial peptides,encapsulated hydrolyzed tannic acid and glucose oxidase in the feed can improve the slaughter rate and antioxidant performance of broilers,and better maintain the intestinal health of broilers.