Dietary zinc, tissue zinc status and sodium-potassium ATPase expression in Atlantic salmon (Salmo salar)

sahar sartipi yarahmadi

Impact of dietary Zn on tissue Zn status and osmoregulation response was studied in Atlantic salmon during the freshwater to seawater transition phase. Six experimental diets were prepared from a basal diet to contain different levels of Zn ranging from 40 to 250 mg Zn/kg. Duplicate groups of Atlantic salmon were fed randomly with one of the six diets for 8 weeks in freshwater and 4 weeks after seawater transfer. The Zn status of the plasma and vertebrae increased linearly with increasing dietary Zn. The Zn status of vertebrae in salmon fed the experimental diets were lower compared to wild post-smolt, except in salmon fed with 250 mg Zn/kg diet. The mRNA expression of NKA α1b was affected by dietary Zn in gills both before and after seawater transfer. Intestinal expression of NKA α1a and α1b responded to dietary Zn at the end of freshwater period but not after seawater transfer. Expression of NKA α1b in the gills and posterior intestine responded to dietary Zn at the end of freshwater phase. In conclusion, dietary Zn and Zn status affects the mRNA expression of NKA gene in the gills and intestine of Atlantic salmon smolts.