Studies on nutritive value of dietary lipids in fish-XXV. Effects of various polyunsaturated fatty acids on growth and fatty acid compositions of rainbow trout Salmo gairdneri, coho salmon Onchorhynchus kisutch, and chum salmon Onchorhynchus keta.

Abstract

This study was conducted to compare the effect of 20:4ω6 with that of 18:2ω6 and 18:3ω3 or a ω3HUFA mixture containing 20:5ω3 and 22:6ω3 on growth and fatty acid compositions of rainbow trout and coho salmon held in freshwater and chum salmon held in both freshwater and sea water. In addition, experiments were conducted to determine whether ?? 12, 19-C22:2 fatty acid with one double bond at ω3 position has an EFA value for these fish, and to determine the EFA requirement of chum salmon in a sea water environment in order to compare it with that in freshwater. The results indicated that 20:4ω6 has the same growth enhancing effect as 18:2ω6 in rainbow trout, coho salmon, and chum salmon In rainbow trout and chum salmon, a ω3HUFA mixture was more effective as EFA that 18:3ω3, but less effective in coho salmon, The ?? 12, 19-C22:2 fatty acid was found to have no EFA value for these fish species, judging from growth and fatty acid compositions of the fish. On the other hand, the requirement of chum salmon for EFA was found to be the same for those held in sea water and in freshwater; the requirement for 18:2ω6 and 18:3ω3 was found to be around 1% of each.