| The Announcement No.194 of the Ministry of Agriculture and Rural Affairs clearly stated that from July 1,2020,my country has completely banned the application of feed antibiotics in livestock and poultry breeding.In order to meet the health and efficiency needs of broilers,it is urgent to find scientifically effective antibiotic substitutes.This experiment studied the effects of adding probiotics in drinking water on the growth performance,intestinal microbiome and metabolome of Lingnan yellow feather broilers,and provided a theoretical basis for the application of composite probiotics in the production of Lingnan yellow feather broilers.Select 270 21-day-old healthy and fast-sized Lingnan yellow feather broilers,with an average weight of 626.71±1.95 g,and randomly divide them into 3 groups with 6 replicates in each group and 15 chickens in each replicate.The initial average weight of each group has no significant difference(P>0.05).The diets of each group were: control group(basic diet);antibiotic group(basic diet + 300 g/t 15% chlortetracycline and 40 g/t 50% virginiamycin);probiotic group(Basic diet + drinking water with compound probiotics).The compound probiotic preparation is 1:1:1 compatible Lactobacillus reuteri,Lactobacillus plantarum and Saccharomyces cerevisiae,and the addition amount of each strain is 1.0×106cfu/ml.The nutritional levels(calculated values)of the three groups of diets were similar.The feeding process is divided into two stages: 22-42-days old and 43-56 days old.The test period is 5 weeks,and the whole process is free to eat and drink.On the 42 nd and 56 th days of the experiment,one chicken was randomly selected for slaughter and sampling in each repeat to study the effects of different treatments on the growth performance,intestinal microbiome and metabolome of Lingnan yellow feather broilers.1.Growth performanceThe growth performance results showed that the average daily gain(ADG)was significantly different between the 22-42-day-old different treatment groups(P<0.05),followed by antibiotic group>probiotic group>control group,average daily feed intake(ADFI))There was no significant difference between the three groups(P>0.05),and the feed-to-weight ratio(F/G)of the probiotic group and the antibiotic group was significantly lower than the control group(P<0.05).There was no significant difference in ADG(P>0.05),no significant difference in ADFI(P>0.05),and no significant difference in F/G(P>0.05)between the different treatment groups aged 43-56 days.22-56 days old,compared with the control group,the ADG of the probiotic group and the antibiotic group increased significantly(P <0.05),there was no significant difference in ADFI(P>0.05),and no significant difference in F/G(P>0.05).2.Small intestine structureAt 42-days of age,there were no significant differences in villus height,crypt depth,and villus to recession ratio between different intestinal segments in each treatment group(P>0.05);at 56 days of age,the depth of ileal crypts was significantly lower in the antibiotic group than the probiotic group Compared with the control group(P<0.05),there was no significant difference between the other groups(P>0.05).3.MicrobiomicIn terms of changes in flora abundance,at the phylum level,compared with the control group,the abundances of Firmicutes and Actinomycetes in the ileum and cecum of the 42-day-old probiotic group showed an increase,Bacteroides and Proteobacteria The abundance of the phylum decreased.The abundance of Bacteroides and Proteobacteria in the ileum and cecum of the 56-day-old probiotic group increased.The abundance of Firmicutes decreased in the ileum and increased in the cecum.At the genus level,compared with the control group,the abundance of Lactobacillus in the ileum and cecum of the 42-day-old probiotic group increased,and the abundance of Enterococcus,Enterobacteriaceae and Bacteroides decreased.In the 56-day-old probiotic group,the abundance of Enterococcus,undetermined Enterobacteriaceae,and Bacteroides in the ileum and cecum of the 56-day-old probiotic group all increased,while the abundance of Lactobacillus decreased in the ileum and increased in the cecum.In terms of microbial community richness and community diversity,compared with the control group,adding compound probiotics to drinking water can significantly increase the ileal chao1 index at 56 days of age.4.MetabolomicsIn terms of free amino acids,compared with the control group,the levels of glutamate,glycine,and aspartic acid in the ileum of the probiotic group increased at 42-days,and the content of aspartic acid and lysine in the cecum decreased at the age of 56 days.The content of proline increased,the content of phenylalanine and leucine decreased,and the content of glutamic acid and histidine increased in the cecum at 56 days of age.Compared with the control group,the proline content in the ileum of the antibiotic group increased at 42-days,the histidine and aspartic acid content in the cecum at 42-days,the proline content in the ileum increased at 56 days,and the cecum at 56 days old.The content of proline,aspartic acid,glutamic acid,ornithine,arginine,histidine,tryptophan and lysine increased.In terms of the small molecular organic acids involved in the tricarboxylic acid cycle,compared with the control group,there was no difference in the ileum of the 42-day-old probiotic group,the succinic acid and fumaric acid content in the cecum of 42-day-old decreased,and the content of pyruvate in the ileum of 56-day-old Decrease,the content of malic acid and isocitrate in the caecum increased at 56 days of age.Compared with the control group,there was no difference in the 42-day-old ileum of the antibiotic group.The content of malic acid,citric acid,fumaric acid and isocitrate in the cecum of 42-day-old increased,while the content of succinic acid in the ileum of 56-day-old decreased.The content of malic acid,succinic acid,citric acid,fumaric acid and isocitric acid increased.In terms of short-chain fatty acids,compared with the control group,there were no significant differences in short-chain fatty acids in different intestinal segments of the probiotic group at different periods(P>0.05).In conclusion,the addition of probiotics in drinking water can significantly improve the growth performance of Lingnan yellow-feather broilers at 22-42-days,and have an important impact on the microbial community structure and lumen metabolism of ileum and cecum of Lingnan Yellow feathered broilers at 42 and 56 days of age. |
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