Vertebral column adaptations in juvenile Atlantic salmon Salmo salar, L. as a response to dietary phosphorus

Radiological detection of nephrocalcinosis in farmed Atlantic salmon Salmo salar L.

“…Radiology has previously been used for assessing vertebrae deformities in Atlantic salmon (Drábiková et al, 2021 ; Holm et al, 2020 ), based on the classification scheme developed by Witten et al ( 2009 ), and there has been a rapid development of the technology (Ou et al, 2021 ) including portable systems, which allow efficient in situ diagnosis. Nephrocalcinosis in Atlantic salmon is mainly identified as amorphous carbonate apatite, a calcium‐dominated mineral (Klykken, Reed, et al, 2022 ), and it has previously been demonstrated that this mineral composition is suitable for x‐ray detection (Smith & Lehr, 1966 ).…”

Elevated Water CO2 Can Prevent Dietary-Induced Osteomalacia in Post-Smolt Atlantic Salmon (Salmo salar, L.)

“…Only 0.5P/20 animals characterized as mineralized were analyzed in 0.5P/20 mg/L group. Animals fed 3P were not analyzed as the analysis of X-ray images, whole mount Alizarin Red S stained specimens, and non-demineralized histological section in the current study and in other studies [ 39 , 40 , 41 ] showed no differences between the mineral content and extent of bone mineralization between Atlantic salmon fed regular and high P in freshwater and seawater.…”

“…The concentration of total and non-bound Ca 2+ , Cl − , inorganic P (P i ), pH, Zn 2+ , ALP, and bicarbonate ions were measured by the Skretting Aquaculture Innovation Laboratory (Stavanger, Norway). The non-bound Ca 2+ , Cl − , and P i were determined as described in [ 39 ]. The total Ca 2+ and pH was measured by ion selective electrode (art.…”

“…Commercial diets commonly contain surplus of dietary P with the aim of enhancing bone mineralization, a preventive measure against the development of vertebral deformities [ 34 , 35 , 36 , 37 ]. However, dietary P that exceeds the nutritional requirements neither improves bone health nor does it enhance the bone formation or bone mineralization in Atlantic salmon [ 38 , 39 , 40 , 41 ]. In addition, excess dietary P leads to vertebral fusions in zebrafish ( Danio rerio ) [ 42 ].…”

“…Under experimental conditions, a period of low dietary P halts bone mineralization while bone matrix formation is maintained. Parr and the early-seawater stages of Atlantic salmon thus develop bone void of minerals at the edges of vertebral bodies and bone trabeculae (osteomalacia) which leads to reduced vertebral centra stiffness [ 39 , 40 , 43 ]. Recovery from low-P diet-associated osteomalacia is possible with a diet containing the required level of P [ 38 , 40 ].…”