Dysimilarities In The Gut Metabolome Of Rabbits With Genetic Differences In Their Resilient Potential

Background: The gut-derived metabolites are key actors in the host-microbiota crosstalk and can have either beneficial or detrimental effects on the host. Gut metabolome could be a potential strategy to enrich the knowledge of host-gut interactions, providing another way of improving key traits such as animal resilience and welfare in livestock systems. Animal resilience has now become a critical livestock trait because of the high demand for more sustainable productions. Environmental variance (V E ), the within-individual variance of traits due to environmental factors, is used as a key measure to improve resilience. Studying the gut microbiome composition can reveal the mechanisms behind animal resilience due to its influence on host immunity. The aim of this study was to identify the gut-derived metabolites underlying the V E of litter size (LS), for which we performed an untargeted gut metabolome analysis in two rabbit populations divergently selected for low (n = 14) and high (n = 14) V E of LS. Partial least square-discriminant analysis and Bayesian statistics were computed to determine dissimilarities in the gut metabolites of the rabbit populations. Results We identified 15 metabolites that can discriminate between rabbit populations with a prediction performance of 99.18% for resilient and 90.42% for non-resilient populations. The most reliable metabolites identified were glycerophosphoglycerol, equol, behenoylcarnitine, arachidoylcarnitine, ethyl beta-glucopyranoside, 3-(4-hydroxyphenyl)lactate, N6-acetyllysine, 5-aminovalerate and succinylcarnitine. A great abundance of acylcarnitines and metabolites from the phenylalanine, tyrosine, and tryptophan metabolism were found in the non-resilient population. Acylcarnitines and metabolites from AAAs (like kynurenine and anthranilate) can impact the inflammatory response and the health status of animals. Conclusions This is the first study to identify gut metabolites that can act as the V E of LS biomarkers as well as resilience biomarkers. The smaller number of acylcarnitines and metabolites derived from the phenylalanine, tyrosine and tryptophan metabolism suggested that resilient animals were better able to cope with stressful events. However, further studies will be needed to determine the causal role of these metabolites in health and disease.