Intestinal Metabolomics of Juvenile Lenok (Brachymystax Lenok) in Response to Heat Stress
Abstract Changes in the metabolic profile within the intestine of lenok (Brachymystax lenok) when challenged to acute and lethal heat stress (HS) are studied using no-target HPLC-MS/MS metabonomic analysis. Of 51 differentially expressed metabolites identified in response to HS, 34 occurred in the positive ion mode and 17 in negative ion mode (VIP > 1, P < 0.05). Changes in metabolites (i.e. alpha-D-glucose, stachyose and L-lactate) related to carbohydrate and glycolysis are identified in HS-treated lenok. Fatty acid β-oxidation in HS-treated lenok was inhibited by accumulation of acetyl carnitine, palmitoylcarnitine, carnitine, and erucic acid. Many amino acids (L-tryptophan, D-proline, L-leucine, L-phenylalanine, L-aspartate, L-tyrosine, L-methionine, L-histidine and L-glutamine) decreased to support energy demands in HS-treated lenok. Oxidative damage in HS-treated lenok was indicated by decreased glycerophospholipid metabolites (i.e. glycerophosphocholine, 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphoethanolamine, 1-palmitoyl-sn-glycero-3-phosphocholine, 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine, and 1, 2-dioleoyl-sn-glycero-3-phosphatidylcholine), and increased oxylipin production (12-HETE and 9R, 10S-EpOME). Oxidative stress increased formation of eicosanoids and dicarboxylic acids, overwhelming the mitochondrial β-oxidation pathway, while minor oxidative pathways (omega-oxidation and peroxisomal beta-oxidation) were likely to be activated in HS-treated lenok.