Platyspondyly and shortness of vertebral column in farmed Atlantic salmon Salmo salar in Norway-description and interpretation of pathologic changes

Abstract

Body malformation due to shortness of the vertebral column, in most cases of unknown cause, has been observed in fish for more than 100 yr. It periodically occurs with high prevalence in farmed Atlantic salmon Salmo salar in Norway, and this paper describes the results of macroscopic, radiographic and histologic examination of parr and seawater-transferred fish. The vertebral bodies in both age groups did not acquire the length that they normally should due to a growth disturbance leading to the condition of platyspondyly and shortness in the column. The pathologic changes became visible at different ages in both groups and the process apparently starts in intervertebral tissues. There was proliferation of connective tissue and blood vessels, and sometimes infiltration with inflammatory cells, around affected vertebrae, especially in seawater-transferred fish. This is the first description of inflammation in abnormally short-spined fish, and it may indicate an infectious etiology, at least in farmed seawater-transferred salmon.

Unilateral perivertebral fibrosis associated with lordosis, kyphosis and scoliosis (LKS) in farmed Chinook salmon in New Zealand

“…In the present study, the severity of the fibrosis was correlated to the radio graphic severity of the LKS, suggesting that a greater degree of fibrosis results in more contraction, and therefore higher severity of LKS. While defects in vertebral bone development are hypothesized to cause most spinal deformities in Atlantic salmon (Fjelldal et al 2012b, Boglione et al 2013b, the possibility that perivertebral inflammation and fibrosis could cause spinal curvature in Atlantic salmon has been previously suggested (Kvellestad et al 2000). Additionally, the possibility that LKS in Atlantic salmon has a neuromuscular rather than a bone aetio logy has also previously been hypothesized (Witten et al 2009).…”

“…Inflammation due to vaccination has been associated with spinal curvature in farmed Atlantic salmon (Kvellestad et al 2000, Berg et al 2012. In Atlantic salmon, vaccination is hypothesized to trigger a systemic autoimmune condition that causes inflammatory lesions to develop in many tissues throughout the body (Koppang et al 2008).…”

Criteria for Safe Use of Plant Ingredients in Diets for Aquacultured Fish

“…Like other developed husbandry, modern finfish aquaculture faces problems such as bone and skeletal deformities, cataracts, heart disorders, unspecific ulceration (Vågsholm & Djupevik 1998;Wall 1998;Kvellestad et al 2000;Farrel 2002;Waagbø et al 2005;Bjerkås et al 2006;Seierstad 2008;Waagbø 2008), various digestive disorders (A.M. Bakke, personal communication) including intestinal colic in Atlantic cod (National Veterinary Institute, 2008), gastric dilatation (bloat) in rainbow trout (Anderson, 2006;Baeverfjord et al, 2006), and intestinal tumours (low incidence) in Atlantic salmon broodstock (National Veterinary Institute, 2008). The mentioned problems have been related to malnutrition, feed, intensive growth and/or unfavorable environmental conditions.…”

Collagen type XI α1 may be involved in the structural plasticity of the vertebral column in Atlantic salmon (Salmo salar L.)

“…This malformation seem to develop late in ontogeny (Berg et al, 2006;Witten et al, 2006;Fjelldal et al, 2007b), and has been associated with factors such as mineral malnutrition , and vaccination (Berg et al, 2006). Compressed vertebrae have been characterized morphologically (Kvellestad et al, 2000;Witten et al, 2005;Fjelldal et al, 2007a;Fjelldal et al, 2007b), however, the molecular pathways underlying the pathogenesis have yet to be identified.…”