How heritable are metabolomic features? An omic based approach in pigs

Dissecting the complexity of production traits in their biological basic components may contribute to define novel phenotypes that can be useful to design new selection strategies in livestock. Metabolites are simple phenotypes that are the products of many different biological processes that underline more complex phenotypes. Metabolites cover a broad range of transient and stable levels over different environmental conditions and physiological stages. Therefore, before metabolites can be used as phenotypes in animal breeding, it is compulsory to estimate their heritability. In this study, we evaluated the heritability of about 200 plasma metabolites analysed in ~900 Italian Large White and ~400 Italian Duroc pigs using a targeted metabolomic platform. All pigs were also genotyped with a high-density single nucleotide polymorphism panel. Pedigree-based and genomic heritabilities were estimated in both pig breeds. The two estimates were highly correlated across different metabolite families. Correlation between breeds was however lower. Heritability was also evaluated in relation to the number of carbons and the degree of unsaturation of different metabolite classes, showing some relation derived by the biochemical features of different biomolecules. According to the obtained results, many metabolites can be considered as proxy phenotypes to substitute more complex phenotypic parameters in estimating breeding values in pigs, opening new avenues to improve complex traits.