title: Metabolic and transcriptional responses of gilthead sea bream (Sparus aurata L.) to environmental stress: new insights in fish mitochondrial phenotyping.
abstract: The aim of the current study was to phenotype fish metabolism and the transcriptionally-mediated response of hepatic mitochondria of gilthead sea bream to intermittent and repetitive environmental stressors: (i) changes in water temperature (T-ST), (ii) changes in water level and chasing (C-ST) and (iii) multiple sensory perception stressors (M-ST). Gene expression profiling was done using a quantitative PCR array of 60 mitochondria-related genes, selected as markers of transcriptional regulation, oxidative metabolism, respiration uncoupling, antioxidant defense, protein import/folding/assembly, and mitochondrial dynamics and apoptosis. The mitochondrial phenotype mirrored changes in fish performance, haematology and lactate production. T-ST especially up-regulated transcriptional factors (PGC1α, NRF1, NRF2), rate limiting enzymes of fatty acid β-oxidation (CPT1A) and tricarboxylic acid cycle (CS), membrane translocases (Tim/TOM complex) and molecular chaperones (mtHsp10, mtHsp60, mtHsp70) to improve the oxidative capacity in a milieu of a reduced feed intake and impaired haematology. The lack of mitochondrial response, increased production of lactate and negligible effects on growth performance in C-ST fish were mostly considered as a switch from aerobic to anaerobic metabolism. A strong down-regulation of PGC1α, NRF1, NRF2, CPT1A, CS and markers of mitochondrial dynamics and apoptosis (BAX, BCLX, MFN2, MIRO2) occurred in M-ST fish in association with the greatest circulating cortisol concentration and a reduced lactate production and feed efficiency, which represents a metabolic condition with the highest allostatic load score. These findings evidence a high mitochondrial plasticity against stress stimuli, providing new insights to define the threshold level of stress condition in fish.
authors.affiliation: Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain. Electronic address: a.bermejo.nogales@csic.es.
authors.forename: Azucena
authors.initials: A
authors.lastname: Bermejo-Nogales
authors.affiliation: Aquaculture and Fisheries Group, Wageningen University, De Elst, 6708 WD Wageningen, The Netherlands. Electronic address: majnederlof@gmail.com.
authors.forename: Marit
authors.initials: M
authors.lastname: Nederlof
authors.affiliation: Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain. Electronic address: l.benedito@csic.es.
authors.forename: Laura
authors.initials: L
authors.lastname: Benedito-Palos
authors.affiliation: Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain. Electronic address: gabriel.ballester@csic.es.
authors.forename: Gabriel F
authors.initials: GF
authors.lastname: Ballester-Lozano
authors.affiliation: Institute of Marine Research Matre, 5984 Matredal, Norway. Electronic address: ole.folkedal@imr.no.
authors.forename: Ole
authors.initials: O
authors.lastname: Folkedal
authors.affiliation: Institute of Marine Research Matre, 5984 Matredal, Norway. Electronic address: rolf.erik.olsen@imr.no.
authors.forename: Rolf Eric
authors.initials: RE
authors.lastname: Olsen
authors.affiliation: Fish Pathology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain. Electronic address: ariadna.sitja@csic.es.
authors.forename: Ariadna
authors.initials: A
authors.lastname: Sitjà-Bobadilla
authors.affiliation: Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain. Electronic address: jaime.perez.sanchez@csic.es.
authors.forename: Jaume
authors.initials: J
authors.lastname: Pérez-Sánchez
mesh_terms: D000818:Animals; D004777:Environment; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D055432:Metabolomics; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D021541:Sea Bream / Q000097:blood / Q000235:genetics* / Q000378:metabolism*; D012677:Sensation / Q000502:physiology; D013312:Stress, Physiological; D014158:Transcription, Genetic
keywords: Husbandry stress; Mitochondrial metabolism; Teleost; Thermal stress