ESTELLE, J. | Search bioRxiv

bioRxiv2024

Genetic selection for residual feed intake impacts the functional redundancy of the gut microbiota in pigs during the growing-finishing period

BackgroundImproving feed efficiency is an unvarying goal in livestock production. The role of gut microbial communities in feed efficiency was investigated in two divergent pig lines selected for their residual feed intake (RFI), which is the difference between the observed feed consumption of an animal and that predicted for its maintenance and production requirements. Hence, RFI is a measure of net feed efficiency. ResultsBy sequencing the 16S rRNA genes from fecal samples, we found that the microbiota of low RFI pigs (LRFI; n=12) was significantly depleted in four operational taxonomic units (OTUs) belonging to Prevotella, Feacalibacterium and Lactobacillus genera by comparison to high RFI pigs (HRFI; n=11). Inferring KEGG orthologs from the 16S rRNA gene sequencing data showed that LRFI pigs have 20% more functional redundancy than HRFI pigs. The inferred orthologs held more discriminative power than the OTU approach, which might be inherently flawed if functionally equivalent OTUs compete for the same niche. ConclusionsGut microbiota of LRFI pigs had different microbial operational taxonomic units and a higher functional redundancy, which were more shared suggesting a role of the gut microbiota in the global feed efficiency according to Tax4Fun but this inference based on 16S data has to be verified in future work.

microbiology↗

bioRxiv2022

Comparative analysis of the caecal tonsil transcriptome in two hen lines experimentally infected with Salmonella Enteritidis

Managing Salmonella enterica Enteritidis (SE) carriage in chicken is necessary to ensure human food safety and enhance chicken breeding viability. Salmonella can contaminate poultry products, causing human foodborne disease and economic losses for farmers. Both genetic selection for a decreased carriage and gut microbiota modulation strategies could reduce Salmonella propagation in farms. Two-hundred and twenty animals from the White Leghorn inbred lines N and 61 were raised together on floor, infected by SE at 7 days of age, transferred into isolators to prevent oro-fecal recontamination and euthanized at 19 days. Caecal content DNA was used to measure individual Salmonella counts (ISC) by droplet digital PCR. A RNA sequencing approach was used to measure gene expression levels in caecal tonsils after infection of 48 chicks with low or high ISC. The analysis between lines identified 7516 differentially expressed genes (DEGs) corresponding to 62 enriched Gene Ontology (GO) Biological Processes (BP) terms. A comparison between low and high carriers allowed us to identify 97 DEGs and 23 enriched GO BP terms within line 61, and 1034 DEGs and 288 enriched GO BP terms within line N. Among these genes, we identified several candidate genes based on their putative functions, including FUT2 or MUC4, which could be involved in the control of SE infection, maybe through interactions with commensal bacteria. Altogether, we were able to identify several genes and pathways associated with differences in SE carriage level. These results are discussed in relation to individual caecal microbiota compositions, obtained for the same animals in a previous study, which may interact with host gene expression levels for the control of the caecal SE load.

genetics↗