Comparison between Atlantic salmon Salmo salar post‐smolts reared in open sea cages and in the Preline raceway semi‐closed containment aquaculture system

• Published in: Journal of fish biology Vol. 93; no. 3; pp. 567 - 579
• Main Authors: Balseiro, Pablo, Moe, Øyvind, Gamlem, Ingrid, Shimizu, Munetaka, Sveier, Harald, Nilsen, Tom O., Kaneko, Nobuto, Ebbesson, Lars, Pedrosa, Cindy, Tronci, Valentina, Nylund, Are, Handeland, Sigurd O.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2018; Wiley Subscription Services, Inc
• Subjects: animal welfare; Animals; Aquaculture; Aquaculture - instrumentation; Aquaculture systems; Cages; Chemical analysis; Containment; Evaluation; exercise; Fibers; Fish; Fresh Water; Freshwater; Freshwater environments; Freshwater fishes; GATA transcription factors; Gene expression; Growth factors; heart; Housing, Animal; Hypertrophy; IGF‐I; Inland water environment; Insulin; insulin-like growth factor I; Insulin-Like Growth Factor I - metabolism; insulin-like growth factor I receptor; Marine fishes; Mortality; muscle; Muscle Development; Muscle Fibers, Skeletal - cytology; Muscle, Skeletal - metabolism; Muscles; Myocardium - metabolism; Norway; Oceans and Seas; Physical Conditioning, Animal; Preline; Proteins; Raceway culture; Receptors; Salmo salar; Salmo salar - anatomy & histology; Salmo salar - blood; Salmo salar - growth & development; Salmon; Seawater; Skeletal muscle; Smolts; Swimming; S‐CCS; training; Transcription; transcription (genetics); Transcription factors; Transcription, Genetic; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; vascular endothelial growth factors; Water analysis; Water currents; Water depth; Water Quality; Norway; IGF-I; Salmo salar; muscle; training; Preline; S-CCS; heart
• ISSN: 0022-1112; 1095-8649; 1095-8649
• DOI: 10.1111/jfb.13659

The use of closed containment (CCS) or semi‐closed containment systems (S‐CCS) for Atlantic salmon Salmo salar aquaculture is under evaluation in Norway. One such system is the Preline S‐CCS, a floating raceway system that pumps water from 35 m depth creating a constant current through the system. Exposing fish to moderate water currents is considered aerobic exercise and it is often perceived as positive for fish welfare, growth, food utilization, muscle development and cardiac health. The present study compared fish reared in the Preline S‐CCS and in a reference open pen. Samples were taken in fresh water before being transferred to the seawater systems and after 1, 2 and 4 months in seawater and analysed for growth, mortality, muscle development and plasma insulin‐like growth factor I (IGF‐I) levels. Moreover, gene transcription were determined in the skeletal muscle [igf‐I, insulin‐like growth factor 1 receptor a (igf1ra) and insulin‐like growth factor 1 binding protein 1a (igf1bp1a)] and cardiac transcription factors [myocyte‐specific enhancer factor 2C (mef2c), gata4 and vascular endothelial growth factor (vegf)]. While the results suggest that post‐smolts in Preline S‐CCS were smaller than reference fish, fish from Preline S‐CCS have less accumulated mortality at the end of the experiment and showed 2.44 times more small muscle fibres than the reference group fish after 4 months in seawater. These results confirmed what was previously observed in the second generation of Preline. Similar levels of big muscle fibres between Preline S‐CCS and reference suggest a similar hypertrophy of muscle fibres even with lower IGF‐I expression in the Preline S‐CCS. Cardiac gene transcription suggests cardiac hypertrophy was observed after 4 months in seawater in the Preline S‐CCS group. Altogether, Preline S‐CCS is a promising technology able to produce more robust S. salar with a faster growth and lower mortality in the subsequent standard open cage system growth period.