Effects Of Several Acidulants On Growth Performance And Health Status Of Slow Yellow-Feathered Broilers

The purpose of this study was to investigate the effect of adding several acidulants to the diets of slow yellow-feathered broilers on growth performance and intestinal function.The experiment selected 600 1-day-old female slow-type yellow-feather broilers with similar body weight and randomly divided them into 5 groups,each group had 10 replicates,and each replicate had 12 broilers,namely: blank control group(CON group),antibiotic control group(ANT group),short-chain fatty acid group(SCFA group),medium-chain fatty acid group(MCFA group),short-chain + medium-chain fatty acid group(SCFA+MCFA group).Among them,the blank control group was fed the basal diet,and the antibiotic control group was supplemented with chlortetracycline 200 g/T in the basal diet,and the amount of acidulant added changed with the test time.The duration of the experiment was 91 days,with 1 to 28 days of age as the early stage of the experiment,29 to 56 days of age as the middle stage of the experiment,and 57 to 91 days of age as the late stage of the experiment.The test results are as follows:1)Before and after the experiment,the addition of antibiotics and acidifiers had no significant effect on ADFI,ADG,and F/G of broilers(P>0.05);in the middle of the experiment,the addition of antibiotics reduced the feed-to-meat ratio of broilers(P<0.05).Both SCFA group and SCFA+MCFA group significantly increased ADG and BW of broiler chickens(P<0.05),while SCFA,MCFA and SCFA+MCFA groups significantly decreased ADFI and F/G of broiler chickens(P<0.05).During the test,the ANT group,SCFA group,MCFA group and SCFA+MCFA group had no significant effect on the liver,spleen,thymus and bursa index of broilers(P>0.05).In the early stage of the test,both the ANT group and the SCFA+MCFA group significantly increased the activity of serum GSH-Px in broilers on28 days(P<0.05);in the mid-term of the test,the SCFA group,the MCFA group and the SCFA+MCFA group all significantly increased the activity of serum GSH-Px in broiler chickens(P<0.05).P < 0.05);SCFA group and MCFA group significantly increased the TAOC activity of broilers(P < 0.05);in the later stage of the experiment,dietary antibiotics and different acidulants had no significant effect on GSH-Px,T-AOC and SOD activities influences.2)In the early stage of the test,the SCFA group significantly reduced the length of the jejunum of broilers(P<0.05),but had no significant effect on the total length of the duodenum,ileum and intestinal tract(P>0.05).The length of different intestinal segments had no significant effect(P>0.05).Before and after the test,the ANT group and different acidulants had no significant effect on the intestinal weight of broilers(P>0.05).),but there was no significant difference between the CON group and the three acidifier-treated groups(P>0.05).In the early stage of the experiment,the ANT group,SCFA group and SCFA+MCFA group all significantly decreased the VH of the duodenum(P<0.05),and the MCFA group and the SCFA+MCFA group significantly decreased the duodenal CD(P<0.05).group significantly increased the VH/CD value of jejunum(P<0.05);in the middle of the test,the MCFA group significantly increased the VH and VH/CD value of the ileum of broiler chickens(P<0.05);in the later period of the test,the SCFA+MCFA group significantly increased the duodenal value of broiler chickens.Intestinal CD value(P < 0.05);ANT group and SCFA group significantly increased the CD value of broiler jejunum(P < 0.05).In the early stage of the experiment,antibiotics significantly increased the relative m RNA expression of Occludin in broilers(P < 0.05),SCFA significantly increased the relative m RNA expression of Mucin-2 and MLCK(P < 0.05),and both MCFA and SCFA+MCFA groups significantly decreased The relative m RNA expression of Claudin-1,Occludin and MLCK in broilers(P<0.05);in the middle of the experiment,the SCFA group significantly increased the relative m RNA expression of Claudin-1 in broilers(P<0.05),while the MCFA group significantly decreased the relative expression of Claudin-1 in broilers(P<0.05).1.The relative m RNA expression of ZO-1 and TGF-β(P<0.05),the SCFA+MCFA group significantly increased the relative m RNA expression of Claudin-1 and Occludin in broilers(P<0.05);in the later stage of the experiment,the ANT group Compared with SCFA+MCFA group,the m RNA expression of Occludin in broilers was significantly increased,and the relative m RNA expression of MLCK was significantly decreased(P<0.05).The SCFA group significantly increased the relative m RNA expression of TGF-β in broilers(P<0.05).3)In the early stage of the experiment,the results of α diversity showed that antibiotics significantly reduced the Goods＿coverage index of the intestinal flora of broilers in the early stage(P<0.05),while the other groups had no significant effect on the α-diversity index of flora in each period(P>0.05).Species composition analysis showed that,at the phylum level,Firmicutes and Bacteroidetes were the dominant flora in the intestinal flora of broilers,and the three types of acidifiers had greater relative abundances to Firmicutes and Bacteroidetes At the genus level,Faecalibacterium,Oscillosis,Bacteroides and Lactobacillus were the dominant genera.The relative abundance of the genus has a greater impact.In the middle of the experiment,there was no significant effect on the α diversity index in each group(P>0.05);at the phylum level,Firmicutes and Bacteroidetes were the dominant flora in the intestinal flora of broilers.It has a certain effect on the relative abundance of Firmicutes and Bacteroidetes;at the genus level,Barnesia,Faecalibacterium,Oscillobacter and Mycobacterium are the dominant genera,and different acidifiers have These genera all have different degrees of influence.In the later stage of the experiment,both the SCFA group and the MCFA group significantly reduced the observed＿species index and Chao1 index of the intestinal flora of broilers(P<0.05).The dominant flora of the tract flora;at the genus level,the relative abundance of Bacteroidetes,Faecalibacterium,and Oscillobacter has a certain degree of influence,and has a greater impact on the relative abundance of Rikenbacteria and Bacteroidetes.4)The chickens sampled in the test did not have pediculitis,the foot features were obvious,and there was no obvious skin abnormality;the intestines of the test broilers were in good shape,the intestinal mucosa was clear,no intestinal congestion lesions,and no intestinal lesions were found.Bleeding spots and necrosis.In summary,short-chain fatty acids can significantly improve the production performance of slow-type yellow-feather broilers throughout the period,enhance serum antioxidant capacity,affect intestinal development and barrier function,inhibit the reproduction of pathogenic microorganisms,and maintain the health of slow-type yellowfeather broilers.situation.