The replacement of fish oil with refined coconut oil in the diet of large rainbow trout (Oncorhynchus mykiss)

Abstract

Three hundred rainbow trout (242.9 ± 6.9 g) were randomly assigned to 12 fibreglass tanks (25 fish/tank). The fish were fed, for 231 days (feeding level: 0.74 % average bw), four experimental diets, containing increasing levels of coconut oil: diet A 0 %, diet B 6 %; diet C 12 % and diet D 13 %, as replacements of herring oil and cod liver oil. Weight gains of fish were > 3 g d-1 and FCR lower than 1.5, for all treatments. No significant difference was observed in the main car- cass traits and whole body composition, but whole fish energy content significantly increased in fish fed diet D (10.68 KJ g-1). Different dietary fatty acid profiles had significant effects on the rainbow trout muscle contents of C10:0, C12:0, C14:0, total n-3, and the main ratios: SFA/USFA; DHA/EPA; DHA/AA, n-3/n-6, but not on total fatty acids content of the muscle.

Keywords

• Rainbow trout, Oncorhynchus mykiss, Refined coconut oil, Performance, Muscle fatty acid composition