Characteristics of Lipid Accumulation Types in Five Species of Fish

Abstract

The characteristics of lipid accumulation were examined in the muscle and liver from five species of commercially important fish. The five species of fish could be clearly divided into two groups based on the lipid ratio of muscle to liver. Puffer and flounder fell into the group with a low lipid ratio, indicating that lipid was accumulated in their liver but not in the muscle. The lipid ratios of red sea bream, amberjack, and striped jack were much higher than those of puffer and flounder, and these fish accumulated lipid in their muscle as well as in their liver. Phosphatidylcholine and triglyceride were main lipid components in the muscle of fish with low and high lipid ratios, respectively. Triglyceride was also a main lipid component of the liver. In addition, considerable amounts of steryl ester were detected in the livers of flounder and puffer. Hepatosomatic index (HSI), the weight percentage of liver to body varied extensively in the five species. The highest and lowest HSI values were obtained in puffer and red sea bream, respectively. The lipid content of liver increased with HSI. The differences of lipid distributioh in muscle and liver were histologically observed. The tissues with high levels of lipid tended to possess numerous osmiophilic droplets. The histology of both muscle and liver showed specific distribution of osmiophilic droplets, supporting the results of chemical analysis of lipid. © 1993, The Japanese Society of Fisheries Science. All rights reserved.