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.

► Atlantic salmon juveniles were fed P supplemented diets for 77 days.
► Adequate juvenile dietary P had long-term positive effects on bone health.
► Blue whiting meal can be used in juvenile feeds.