Effects of Lipid Nutrition on Hepatopancreatic Ultrastructure of Eriocheir sinensis Larvae (Crustacea:Decapoda)

From March to July of 1998 Eriocheir sinensis larvae were cultured by feeding with rotifers treated with lipid enrichment 50 DE-G at early zoeal developmental stages and with Artemia nauplii at postlarval developmental stages.The hepatopancreatic ultrastructure of the larvae was observed through transmission electronic microscopy.The results show:1) the hepatopancreatic length increase with the larval development,and the cells of hepatopancreas consist of four types,which are embryo cell (E cell),resorptive cell (R cell),fibrillar cell (F cell) and secretory cell (B cell) respectively;2) E cells are stem cells that can be differentiated into other three types of cells;3) B cells have 1 to 2 large vacuoles and numerous rough endoplasmic reticulum (Rer);4) R cells store some nutrients such as lipid droplets for the larval development and have some vacuoles,large quantity of smooth endoplasmic reticulum (Ser) and free ribosomes,and many mitochondria with high electron density matrix and plenty of ridges can be observed in R cells;5) F cells have plenty of zymogen granules near the apical cells;6) compared with hepatopancreatic ultrastructure of the larvae fed with rotifers cultured by bakers yeast,significant difference can be observed in R cells.After enriched by lipid nutrients,R cells have more lipid droplets,and structural changes of mitochondria can be seen.The results indicate that ultrastructural changes in R cells of hepatopancreas could reflect the nutritional status of the larvae.