AUTHOR=Balbuena-Pecino Sara , Riera-Heredia Natàlia , Vélez Emilio J. , Gutiérrez Joaquim , Navarro Isabel , Riera-Codina Miquel , Capilla Encarnación 

TITLE=Temperature Affects Musculoskeletal Development and Muscle Lipid Metabolism of Gilthead Sea Bream (Sparus aurata)

JOURNAL=Frontiers in Endocrinology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2019.00173

DOI=10.3389/fendo.2019.00173

ISSN=1664-2392

ABSTRACT=<p>World population is expected to increase to approximately 9 thousand million people by 2050 with a consequent food security decline. Besides, climate change is a major challenge that humanity is facing, with a predicted rise in mean sea surface temperature of more than 2°C during this century. This study aims to determine whether a rearing temperature of 19, 24, or 28°C may influence musculoskeletal development and muscle lipid metabolism in gilthead sea bream juveniles. The expression of growth hormone (GH)/insulin-like growth factors (IGFs) system-, osteogenic-, myogenic-, and lipid metabolism-related genes in bone and/or white muscle of treated fish, and the <italic>in vitro</italic> viability, mineralization, and osteogenic genes expression in primary cultured cells derived from bone of the same fish were analyzed. The highest temperature significantly down-regulated <italic>igf-1, igf-2</italic>, the receptor <italic>igf-1ra</italic>, and the binding proteins <italic>igfbp-4</italic> and <italic>igfbp-5b</italic> in bone, and in muscle, <italic>igf-1</italic> and <italic>igf-1ra</italic>, suggesting impaired musculoskeletal development. Concerning myogenic factors expression, contrary responses were observed, since the increase to 24°C significantly down-regulated <italic>myod1</italic> and <italic>mrf4</italic>, while at 28°C <italic>myod2</italic> and <italic>myogenin</italic> were significantly up-regulated. Moreover, in the muscle tissue, the expression of the fatty acid transporters <italic>cd36</italic> and <italic>fabp11</italic>, and the lipases <italic>lipa</italic> and <italic>lpl-lk</italic> resulted significantly increased at elevated temperatures, whereas β-oxidation markers <italic>cpt1a</italic> and <italic>cpt1b</italic> were significantly reduced. Regarding the primary cultured bone-derived cells, a significant up-regulation of the extracellular matrix proteins <italic>on, op</italic>, and <italic>ocn</italic> expression was found with increased temperatures, together with a gradual decrease in mineralization along with fish rearing temperature. Overall, these results suggest that increasing water temperature in this species appears to induce unfavorable growth and development of bone and muscle, through modulating the expression of different members of the GH/IGFs axis, myogenic and osteogenic genes, while accelerating the utilization of lipids as an energy source, although less efficiently than at optimal temperatures.</p>