Zinc gluconate and zinc sulphate as dietary zinc sources for Atlantic salmon

Different chemical forms of essential minerals and trace elements supplemen ted to feed may show different bioavailability in fish, The present experim ent was performed to compare an organic zinc form (Zn-gluconate) with zinc sulphate as dietary zinc sources for Atlantic salmon. Triplicate groups of fish were fed commercial fish meal based diets supplemented with either a l ow zinc level (50 mg Zn kg(-1)) or medium zinc level (180 mg Zn kg(-1)) as zinc gluconate or zinc sulphate for 6 months. Growth, mortality and feed co nversion were recorded through the experiment. Fish were sampled initially and every month for zinc status analyses measured as whole-body zinc concen tration. After 4 and 6 months, vertebral zinc concentration was measured an d serum zinc was analysed at the end of the experiment. There were no diffe rences in growth or mortality during the experiment. The results showed a s ignificant effect of dietary zinc supplementation level on zinc status in f ish for both zinc forms. However, there were no differences in zinc status between groups given different zinc forms. In conclusion, the present exper iment showed that zinc sulphate and zinc gluconate are equally efficient as zinc supplements in salmon feeds within the concentrations normally found in salmon feed.