Heat shock during early somitogenesis induces caudal vertebral column defects in Atlantic salmon (Salmo salar)

Abstract

In several terrestrial vertebrates, heat shock (HS) during somitogenesis causes vertebral deformities. To determine if vertebral deformities can occur due to sudden temperature changes during early development in fish, Atlantic salmon embryos were HS treated during somitogenesis. Ten months later these individuals displayed a high prevalence of caudal vertebral column condensations (27-34%). The defects were located caudally of the abdominal cavity, displaying an even distribution in this region independent of time of HS. To determine if HS disturbed vertebral development during somitogenesis, two genes coding for markers of skeletal development were identified, namely, the secreted protein Shh (Sashh) and the transcription factor Twist (Satwist). These proteins are involved in the proliferation and specification of presumptive skeletal cells (sclerotome) in vertebrates. The spatial expression pattern of sashh and satwist in salmon indicated a functional conservation of these proteins. Furthermore, HS embryos displayed expressional disturbance in both sashh and satwist, indicating an effect of HS on sclerotomal cell patterning. However, the HS-protecting ability in embryos seems to be individually regulated because reduction in gene expression was not detected at all stages; in addition, HS did not induce somitic disturbance and vertebral deformity in all embryos.

Rapid growth causes abnormal vaterite formation in farmed fish otoliths

“…Experiment 2 -effects of temperature shock and light regime on vaterite prevalence Salmon eggs (commercial strain B) were reared at 6°C in complete darkness, and hatched in January 2012 (see Wargelius et al, 2005, for experiment details). Heat-shock treatments exposed alevins to 12°C for 24 h at 20 degree-days (20dC), 220dC or no heat-shock (control).…”

“…Third, hatcheries often use continuous light to enhance growth and suitability for sea-cage transfer (Saunders et al, 1985), which can affect physiology and development (Oppedal et al, 2003). Finally, temperature fluctuations within hatcheries may influence vaterite formation (Sweeting et al, 2004), which may be particularly important in early life (Wargelius et al, 2005). As otolith formation is a complex interaction between genetic and environmental factors (Radtke and Shafer, 1992), it is important to evaluate the separate and interacting effects of all possible factors.…”

Gross Abnormalities in Tilapia

“…Non-heritable abnormalities can be caused by disease (e.g., Hoffman et al, 1962;Hoffman, 1984;Pasnik et al 2007);injury (e.g., Breeder, 1953;Gunter and Ward, 1961); environmental disturbances (e.g., Rogers 1956;Garside, 1959;Yamamoto et al 1963;Schröder, 1969;Mayer et al, 1978;Couch et al, 1979;Backiel et al, 1984;Grady et al, 1992;Wargelius et al, 2005;Sun et al, 2009); nutritional deficiencies (e.g., Rucker at al., 1970;Andrews and Murai, 1975;Lim and Lovell, 1978;Murai and Andrews, 1978), and culture conditions (e.g., Romanov, 1984;Wiegand et al, 1989;Leary et al, 1991;Krise and Smith, 1993;Sawada et al, 2006). They can also be the result of developmental errors (e.g., Tave et al, 1982;Dunham et al, 1991;Handwerker and Tave, 1994;Tave and Handwerker, 1994).…”

Continuous light affects mineralization and delays osteoid incorporation in vertebral bone of Atlantic salmon (Salmo salar L.)

“…Another marker, collagen type I alpha 2 (col I; also known as col1a2) was selected, because collagen I is the major structural protein that is incorporated into bone. Two of the genes used in this study, shh (Wargelius et al, 2005b) and mgp (Laize et al, 2005), have been cloned and/or identified previously in Atlantic salmon, and the other genes have been identified by sequence homology; alp, has been identified in fugu (Takifugu rubripes, GenBank acc. no.…”