Study of changes in macro elements Ca, Mg, Na and K in eggs of rainbow trout (Oncorhynchus mykiss) at different incubation stages

We studied rainbow trout eggs requirements to macro elements Ca, Mg, Na and K at different stages of incubation period. The research was carried out at Namroud rainbow trout hatchery center in winter 2005. Two incubators in equal conditions were selected. The first was stocked with approximately 60000 eggs and the second had no eggs. A total of 100 fertilized eggs were sampled and assessed for the elements before introduction of the eggs to the incubator. Weekly samples were taken from the eggs and water of the first and second incubator. The sampled eggs were digested by Tripathi method and concentration of the elements in eggs extract was measured by ICP apparatus. In addition, variation of these elements between input and discharge water of both incubators was investigated…