This study investigated the cecal microbiota and serum metabolite profile of chickens fed with plant essential oils (PEO) or virginiamycin (VIRG) using high-throughput 16S rRNA gene sequencing and untargeted metabolomics approach. the main aim of this work was to explore the biochemical mechanisms involved in the improved growth performance of antibiotics and their alternatives in animal production. The results showed that both PEO and VIRG treatment significantly increased the relative abundance of phyla Bacteroidetes and decreased the abundance of phyla firmicutes and genus of Lactobacillus in cecal microbiota of chickens. compared to the control group (ct group), the relative abundance of genus of Alistipes, unclassified Rikenellaceae, Roseburia, and Anaeroplasma was enriched in the peo group; that of genus Bacteroides, Lachnospiraceae, and unclassified Enterobacteriaceae was enriched in the cecal microbiota of the ViRG group. Untargeted metabolomics analyses revealed that the PEO treatment modified 102 metabolites and 3 KEGG pathways (primary bile acid biosynthesis and phenylalanine metabolism) in the cecal microbiota, and 81 metabolites and relevant KEGG pathways (fructose and mannose metabolism, biosynthesis of unsaturated fatty acids, and linoleic acid.) in the serum of the chicken. Compared to the CT group, VIRG treatment group differed 217 metabolites and 10 KEGG pathways in cecal contents and 142 metabolites and 7 KEGG pathways in serum of chickens. pearson's correlation analysis showed that phyla Bacteroidetes and genus of Bacteroides, Alistipes, and unclassified Rikenellaceae (in the VIRG and PE group) were positively correlated with many lipid metabolites. However, phyla firmicutes and genera Lactobacillus (higher in the ct group) were negatively correlated with the lipid and thymine metabolism, and positively correlated with hydroxyisocaproic acid, cytosine, and taurine. this study shows that dietary supplementation with peo and VIRG altered the composition and metabolism profile of the cecal microbiota, modified the serum metabolism profile. The intestinal microbiota, the population of microorganisms that inhabit the intestine, plays an important role in the intestinal morphology, immunity, nutrient digestion and absorption, and host health 1-3. Many studies have demonstrated that intestinal microbiota participates in many metabolic pathways, such as lipid metabolism and amino acid synthesis 4,5. The mechanism by which PEO promote growth of may be alter gut microflora and hence improved absorption of nutrients 6 , increase absorption of micronutrients in the small intestine 7 and reducing the deleterious effects of the microbial metabolites 8-10. There are many alternatives to antibiotics, such as acidifiers, probiotics, oligosaccharides, and plant extracts, which play a growth promoting role by regulating gut microbes in pig and poultry 11. Plant essential oils (PEO), which can be extracted from plants by steam distillation, extrusion, or solvent extraction 12,13 , serve as alternatives for antibi...

Background: Necrotic enteritis, which is caused by Clostridium perfringens, has resulted in more than $2 billion losses in the poultry industry every year. Due to the ban of antibiotics in feed industry, alternatives like environment improvement and probiotics have been found to be effective as well. In our study, we aim to explore the protective effect of Lactobacillus plantarum supplementation on CP infected chickens in two environments. Results:The results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions. In the specific pathogen free or free-range system environment, dietary supplementation with LP obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 mRNA in ileum mucosa, then reduced the mRNA expression level of TNF-α gene in the ileum mucosa. LP treatment significantly reduced the contents of total protein, total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens. Conclusions:The specific pathogen free environment contributed to the recovery of pre-inflammation of the chickens, and free-range system environment contributed to the repair of damage in the later stages of chicken inflammation. Supplementation of LP in FRS environment was more conducive to the recovery of CP infected in chickens.

Background Necrotic enteritis, which is caused by Clostridium perfringens, has resulted in more than $2 billion losses in the poultry industry every year. Due to the ban of antibiotics in feed industry, alternatives like environment improvement and probiotics have been found to be effective as well. In our study, we aim to explore the protective effect of Lactobacillus plantarum supplementation on CP infected chickens in two environments. Results The results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions. In the specific pathogen free or free-range system environment, dietary supplementation with LP obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 mRNA in ileum mucosa, then reduced the mRNA expression level of TNF-α gene in the ileum mucosa. LP treatment significantly reduced the contents of total protein, total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens. Conclusions The specific pathogen free environment contributed to the recovery of pre-inflammation of the chickens, and free-range system environment contributed to the repair of damage in the later stages of chicken inflammation. Supplementation of LP in FRS environment was more conducive to the recovery of CP infected in chickens.

Background Necrotic enteritis, which is caused by Clostridium perfringens, has resulted in more than $2 billion losses in the poultry industry every year. Due to the ban of antibiotics in feed industry, alternatives like environment improvement and probiotics have been found to be effective as well. In our study, we aim to explore the protective effect of Lactobacillus plantarum on CP infected chickens in two environments. ResultsThe results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions. In the specific pathogen free or free-range system environment, dietary supplementation with LP obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 mRNA in ileum mucosa, then reduced the mRNA expression level of TNFα gene in the ileum mucosa. LP treatment significantly reduced the contents of total protein, total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens.Conclusions The specific pathogen free environment contributed to the recovery of pre-inflammation of the chickens, and free-range system environment contributed to the repair of damage in the later stages of chicken inflammation. Supplementation of LP in FRS environment was more conducive to the recovery of CP infected in chickens. BackgroundNecrotic enteritis (NE), which is caused by Clostridium perfringens (CP), is a disease of the major in the global poultry industry which has resulted in about 6-7 billion US dollars loss per year [25]. C. perfringens type A is a gram-positive, spore-forming, rod-shaped bacterium, which is the main pathogen that causes clinical and subclinical necrotic enteritis in poultry [40, 37]. The key factor for the development of NE is the change of gastrointestinal environment, which creates favorable conditions for the growth of CP. Antibiotics are considered to be effective measures to reduce the incidence of NE, but due to ban on feeding growth-promoting antibiotics in Europe, there has been an increase in the incidences of NE [14]. Environment improvement (intensive feeding patterns) and the extensive use of antibiotics have played an important role in preventing CP infection and the incidence of NE in the past decades [31]. Owing to the ban on the use of antibiotics in feed industry, This work was supported by National Natural Science Foundation of China (project no. 3146068; Beijing, P. R. China). Authors ContributionsNZ and TX designed the experiments and wrote the paper; LY, YC, JW, and MH performed the experiments and collected the samples. TX and LY analyzed the data. NZ and TX were responsible for the final content. All of the authors have read and approved the final manuscript.