Impacts of thermal acclimatization on fish skeletal muscle

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Vol. 280; p. 111409
• Main Authors: Moran, Clinton J., Coughlin, David J., Jebb, Kamryn E., Travitz, Leksi, Gerry, Shannon P.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-06-2023
• Subjects: Abductor superficialis; Acclimation; Acclimatization; Acclimatization - physiology; Animals; Fishes - physiology; Immunohistochemistry; Kinetics; Muscle, Skeletal; Perciformes - physiology; Temperature; Immunohistochemistry; Acclimatization; Kinetics; Abductor superficialis; Acclimation
• ISSN: 1095-6433; 1531-4332
• DOI: 10.1016/j.cbpa.2023.111409

Thermal acclimation allows ectotherms to maintain physiological homeostasis while occupying habitats with constantly changing temperatures. This process is especially important in skeletal muscle which powers most movements necessary for life. We aimed to understand how fish skeletal muscle is impacted by acclimatization in the laboratory. To accomplish this, we compared muscle contraction kinetics of four-week lab acclimatized fish (at 20 °C) to fish taken directly from the field when sea surface temperatures were similar to lab treatment temperature (ocean temperature ranged from 17.7 to 19.9 °C in the four weeks prior to collection at 20 °C). To examine these effects, we chose to study tautog (Tautoga onitis) and cunner (Tautogolabrus adspersus) from Long Island Sound. We found that timing of contraction kinetics in cunner and tautog did not differ from the lab acclimatized and field acclimatized groups. However, lab acclimatized cunner produced greater contraction force than fish taken directly from the field. This increased force production allowed lab acclimatized cunner to produce greater power when compared to cunner from the field treatment. Furthermore, laboratory acclimatized cunner did not express any slow myosin heavy chain, suggesting that their muscle had transitioned to mostly fast twitch fibers after being held at a constant temperature in the lab. None of these effects were seen in tautog. In this work we highlight the importance of considering the impacts laboratory conditions have on experimental conditions.
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•Contraction kinetics is similar between lab acclimatized and field treatment groups.•Lab acclimatized cunner produce greater power than fish from the field.•Cunner muscle is capable of switching from slow to fast twitch.