Inadequate phosphorus nutrition in juvenile Atlantic salmon has a negative effect on long-term bone health

In order to study the short-term effects of dietary P levels during juvenile rearing on mineral status (bone ash content). and its long-term effects on the development of vertebral deformities (radiography and external examination), triplicate groups of Atlantic salmon juveniles (1.3 g) were fed blue whiting meal (67%) based diets added 0 (0P), 3 (3P) and 6 (6P) g inorganic P kg(-1) (15, 18 or 21 g kg(-1) total P) for 77 days (18.3 g), and then followed up on a common commercial diet for 432 days (1927 g). At the termination of the period on the experimental feeds the vertebrae of the fish fed the 0P diet had a significantly lower ash weight than those fed the 3P and 6P diets, while there was no difference in the occurrence of radiological deformed fish. 252 days later, the 0P (31.7 +/- 5.5%) dietary group had a significant higher occurrence of radiological deformed fish than the 6P dietary group (9.4 +/- 5.6%), while the 3P dietary group displayed an intermediate level (19.7 +/- 2.8%). At termination, 432 days after the termination of the experimental feeds, the 0P dietary group (5.9 +/- 0.7%) had a significantly higher prevalence of externally deformed fish compared to the 3P (3.5 +/- 0.9%) and 6P (2.0 +/- 0.4%) dietary groups. This was mainly caused by a higher level of deformities in the caudal region (V31-58) of the vertebral column in the 0P group. There were no effects on mortality or growth of the present diets. The results show that inadequate P nutrition in a short period during the juvenile stage can predispose Atlantic salmon to develop vertebral deformities following seawater transfer. (C) 2012 Elsevier B.V. All rights reserved.