Abstract
The total number of intestinal microbiotas is low, and the intestinal tract develops rapidly and imperfectly at the embryonic stage. Embryonic period as a particular physiological stage is an important time window to explore how to regulate organismal health by probiotics. Therefore, this experiment was conducted to investigate the effect of embryonic injection of Lactobacillus plantarum PA01 at embryonic d 14 (E14) on the microbiome of the contents of the gizzard, cecum at embryonic d 20 (E20) and cecum at d 1 posthatch (D1) by 16S rRNA sequencing. Results showed that PA01 had no significant effect on broiler body weight and yolk sac weight at E20 and D1 (P > 0.05). PA-01 altered the Shannon index and β diversity of the gizzard at E20 (P < 0.05), increased the abundance of Firmicutes (P < 0.05), and decreased the relative abundance of Proteobacteria, Bacteroidota, and Actinobacteriota (P < 0.05). At the genus level of the microbiota, PA01 significantly increased the relative abundance of Lactiplantibacillus (P < 0.05). At 20 embryos, PA01 altered the α and β diversity indices (P < 0.05) and decreased the relative abundance of Salmonella (P < 0.05) of the cecal microbiota. The biomarkers of PA01 group were Lactobacillales, Blautia, Lachnospiraceae, and Asinibacterium. Embryonic injection of PA01 altered the E20 intestinal microbes. PA01 altered the β-diversity index of the 1-day-old cecum (P < 0.05), and there was no significant effect on microbial composition at the phylum and genus level (P > 0.05). LefSe analysis revealed that the biomarkers of the PA01 group were Lactobacillaceae, Lactiplantibacillus, Moraxellaceae, and Acinetobacter. Biomarkers in the Con group were Devosia, Bacillus, Nordella, Mesorhizobium, and Pseudolabrys. PA01 increased acetic acid in the gastrointestinal tract at E20 along with acetic and butyric acid in cecum of 1-day-old. In conclusion, embryo-injected L. plantarum PA01 altered the structure and metabolites of the microbial flora before and after hatching, in particular promoting the colonization of Lactobacillus.