Metabolomic profiling of the heat stress response in Iberian piglets

Heat stress (HS) can negatively affect swine physiology compromising its productivity. Metabolomics provides a powerful tool to uncover the biochemical mechanisms underlying these physiological changes. We investigated the impact of HS on the plasma metabolome of 20 weaned castrated male Iberian piglets (14.76 ± 2.97 kg). Animals were housed individually under thermoneutral (TN) conditions for 7 days, after which temperature was increased to 30°C for an additional 7 days. Blood samples were collected at three timepoints: before HS (T0), two days after HS onset (T2, acute), and seven days after HS onset (T7, chronic). Samples were analyzed using HPLC-based metabolomics (Metabolon Inc.). Missing values were imputed using the MICE approach, and data were corrected for fractional growth rate and batch as fixed effects, with individuals as random effects in a mixed linear model. Model residuals were used for paired timepoint comparisons using the Boruta algorithm to identify discriminant metabolites. Metabolites with a p<0.05 were consider significant using Mann-Whitney tests followed by Bonferroni correction. We identified 10 differentially abundant metabolites (DAM) between T0 and T2, 20 DAM between T0M and T7M and 36 DAM between T2 and T7, in which amino acid metabolism was the most abundant super-pathway (30.56%) and long-chain polyunsaturated fatty acids constituted the most represented sub-pathway (11.11%). The most abundant super-pathway among all the DAM was amino acid metabolism (33.70%), followed by lipid and carbohydrate metabolism (18.48% and 10.87%, respectively). These results indicate that different metabolic changes were observed between acute and chronic HS. This work has received funding from the European Union’s Horizon Europe research and innovation programme under the grant agreement No. 101059609 (Re-Livestock project) and has been supported by COST Action CA22112.