Fatty acid composition in sea cucumber Apostichopus japonicus fed with microbially degraded dietary sources

Fatty acids (FAs) in the body walls of sea cucumber, Apostichopus japonicus, reared under diet-administered conditions were analysed to determine the accumulative status of dietary FAs. Four test diets different in diet source and microbial degradation, that is, a diet composed of powdered pennate diatoms (diet PD), one microbially degraded of diet PD (diet PDM), one composed of brown algae [tangle weed, Saccharina (Laminaria) longissima (Miyabe); diet BA], and one microbially degraded of diet BA (diet BAM), were fed to juvenile A. japonicus, respectively, for 2 months and the FA composition of the juvenile body wall was determined. FAs in body wall were influenced and changed by diet source and microbial degradation of diet. Degradation significantly promoted juvenile's growth and increased iso-15:0 in the body wall; however, iso15: 0 was not a growth factor. FA 20:4n6 and 20:5n3 were dominant in all groups despite being a minor dietary constituent, suggesting that these FAs can be readily accumulated or synthesized in the animal.