Variations circadiennes des acides aminés libres de l'hemolymphe de Penaeus japonicus

[Circadian variations in hemolymph lipids and lipoproteins and in hepatopancreatic lipids of the shrimp Penaeus japonicus]

Lipids content of the haemolymph and the hepatopancreas in the decapod Crustacean P. japonicus exhibits a bicircadian rhythm characterized by one maximum in the night and another one during the day. The maximal values in the haemolymph are approximately two and a half times greater (8 mg/ml) than minimal ones (3 mg/ml). Variations are less important in the hepatopancreas. A bicircadian rhythm of lipid classes in the haemolymph is observed very significantly in concentration of polar lipids and free sterols with maximal values (6.87 mg/ml and 0.59 mg/ml) and minimal values (2.63 mg/ml and 0.23 mg/ml) respectively. Polar lipids are the major lipid fractions in the haemolymph (87%). The electrophoretic behaviour of haemolymph lipoproteins is determined.