COMPARATIVE STUDIES OF MICRO-ULTRASTRUCTURE AND FATTY ACID COMPOS ITION OF NORMAL AND ALBINO HEPATOPANCREAS OF CHINESE MITTEN CRAB ERIOCHEIR SINENSIS

In recent years, Eriocheir sinensis with white hepatopancreas was frequently observed in the cultivation p rocess,and the white hepatopancreas was called hepatopancreas albinism, but the albino hepatopancreas was mainly observed inmale crabs.The study was investigated to determine the factors and causes resulting in that phenomenon during the Eriocheir sinensis cultivation process.The animals used in this experiment were collected from the different cultivation locations in the YangchengLake.Theywere quickly sacrificed after being taken to the laboratory, and then hepatopancreaswere dissected from the experimental crabs.The lipid classes, fatty acid composition and microultrastructure of the crabswith albino hepatopancreaswere determined, compared with those crabswith normal hepatopancreas.According to the results, significant difference wasfound at hepatosomatic index and total content of lipid.The lipid classes of two kinds crabswere almost the same, the contents of neutral lipid were 86.45% in normal hepatopancreas and 89.30% in albino, and the main componentwas triacylg lyceride.The content of C.8:. was 8.00% and 37.75% , respectively, higher than any other kind of fatty acid in neutrallip id.The contents of C5∶0, C6∶., C0∶. and EPA of normal crabs were higher than albino crabs, but the contents ofC.6∶0 and C.8∶. were opposite.The fatty acid composition of polar lip id in the hepatopancreas of two kinds of crabswassimilar to that of the neutral lip id.The content of C.8∶. was the highest and the content of albino crabs was significanthigher than normal ones (p<0.0.).In normal crabs, epithelial cell wall of hepatic tubule was comp rised of monolayercells.B cell and R cell arranged in the order.The microvilli and enteric coat at the top of cells showed comp lete structure.The lumen of hepatic tubule contained some inclusion. In contrast, the cells of ep ithelial cellwall of hepatic tubule arranged in disorder in the albino crabs.The microvilli and its mucosal disappeared. Cavity appeared irregularly in hepatictubule, and cells separating from lumen walls were observed. It is estimated that the color of hepatopancreas has tight connection with differences of lipid content.The hepatopancreasof normal crabs have low content of water but high content of lipid, therefore, it contained more lipidsoluble vitamins andcoloringmatters than albino ones,which leads to yellow color.However, the result of albinol oneswas opposite.The accumulation of lipid soluble vitamins and coloringmatterswere prevented,which leads to white color.According to some surveys, fattyacid composition and microultrastructure of albino hepatopancreas cells has tight relationship to the lack of EFA.