Physical indices changes and survival in rainbow trout (Oncorhynchus mykiss) eggs kept in different environments for different time duration

In this study, short-term storage of rainbow trout (Oncorhynchus mykiss) eggs in different environments and time periods was investigated. For this purpose, fish eggs were stored for one, four and seven days at refrigerator temperature (4°C) and in the natural ovarian fluid, Cortland buffered with Hepes and Tris-HCl, at pH=8.4. The individual egg wet and dry weights, egg diameter, storage fluid pH, fertilization, eyed and hatching percentage were measured. The results showed that egg storage time did not change wet and dry weights significantly, while egg diameter were increased significantly (P<0.05). The pH level decreased significantly with increasing storage time in all environments (P<0.05) although the highest decrease were observed in ovarian fluid,  Survival rates including fertilization, eyed and  hatching rates  were measured and indicated that the highest survival rates were obtained for eggs stored in Hepes environment. So, the artificial medium buffered with Hepes could be recommended for short-term storage of rainbow trout eggs.