牛至精油对羔羊盲肠组织形态、菌群结构及功能的影响OA

This experiment aimed to screen the optimal supplementation level of oregano essential oil(OEO)for Saanen goat kids.Forty-eight male Saanen goat kids with similar birth weights were selected and randomly assigned to three treatment groups(4 replicates per group,4 kids per replicate).At 7 days of age,the kids were fed starter diets supplemented with 0 g/d(CON),1 g/d(OEO1),and 2 g/d(OEO2)OEO.At 70 days of age,the kids were weighed in the morning after fasting,and 6 kids from each group were randomly slaughtered to collect cecal tissue and contents for analysis.The results showed that OEO had no significant effects on cecal pH or tissue morphology(P＞0.05).A total of 1,522,540 high-quality reads and 5,157 ASVs were obtained from the 18 cecal content samples.The chao1,shannon,simpson,observed_features,and pielou_e indices in the OEO2 group were extremely higher than those in the OEO1 and CON groups(P＜0.01),while the dominance index in the CON group was significantly higher than that in the OEO1 and OEO2 groups(P＜0.01).LEfSe analysis revealed that the OEO1 group was primarily characterized by Oscillospiraceae within the order Oscillospirales.The OEO2 group showed significant enrichment of Christensenellaceae_R-7_group and Monoglobus(phylum Bacillota),as well as Bacteroides,Prevotellaceae UCG-004,and Rikenellaceae_RC9_gut_group(phylum Bacteroidota).The CON group showed significant enrichment of Agathobacter,Coprococcus,and Ruminococcus(phylum Ba-cillota).Tax4Fun functional prediction analysis indicated that the cecal microbiota were primarily involved in carbohydrate metabolism,membrane transport,replication and repair,amino acid metabolism,transla-tion,energy metabolism,nucleotide metabolism,signal transduction,cell motility,and metabolism of co-factors and vitamins.Correlation analysis showed that pH was positively correlated with Agathobacter and unclassified_Clostridia_UCG.014(P＜0.05),and negatively correlated with Christensenellaceae_R.7_group,unclassified_UCG.010,and Rikenellaceae_RC9_gut_group(P＜0.05).Relative cecal volume was negatively correlated with Bacteroides(P＜0.05),and mucosal layer thickness was negatively correla-ted with Bacteroides,unclassified_Eubacterium_coprostanoligenes_group,and Monoglobus(P＜0.05).In conclusion,the use of OEO in goat kid production can effectively improve the structure and function of the cecal microbiota,and the optimal dietary supplementation level of oregano essential oil is 2 g/d.