Comparison of lipid properties between wild and cultured ayu

Lipid properties were compared between cultured and wild ayu Plecoglossus altivelis obtained from 9 different producing districts of Japan. The cultured ayu was characterized by high accumulation of triglycerides in intraperitoneal fat body (IPF) and muscle. While the IPF ratio of wild ayu ranged between 0.1 and 8.6% (average 1.8•}1.6%), that of cultured ayu ranged between 1.5 and 15.1% (average 7.5•}3.6%). The muscle lipid level of cultured ayu (8.2•}2.5%) was extremely higher than that of wild ayu (3.4•}1.7%). However, the ranges of both IPF ratio and muscle lipid level of cultured ayu overlapped with those of the wild ayu. Fatty acid composition of muscle triglycerides was compared between cultured and wild ayu. According to muscle lipid level and fatty acid composition, the ayu could be divided into two groups. One group consisted mainly of the samples obtained from cultured ayu, and the other group from wild ayu. However, there were samples in the cultured ayu which could be categorized to the wild fish group. The results show the possibility that technical advancement will enable us to reduce the IPF ratio and muscle lipid level of cultured ayu to•@the values of wild ayu.