Effects of starvation on digestive enzymatic activities in the red claw crayfish Cherax quadricarinatus juveniles

NATALIA CALVO; HERNÁN J. SACRISTÁN; LAURA S. LÓPEZ GRECO

San José

Congreso; Summer Meeting of The Crustacean Society (TCS) jointly organized with the Latin American Association of Carcinology (ALCARCINUS); 2013

Effects of starvation on digestive enzymatic activities in the red claw crayfish Cherax quadricarinatus juveniles    Natalia S. CALVO; Hernán J. SACRISTÁN; Laura S. lÓPEZ GRECO   Biology of Reproduction and Growth in Crustaceans. Department of Biodiversity and Experimental Biology, FCEyN,University of Buenos Aires, Cdad. Univ. C1428EGA, Buenos Aires, Argentina. IBBEA-CONICET, Argentina   Presenting author: laura@bg.fcen.uba.ar   The hepatopancreas is considered the major storage organ in decapods crustaceans. It mainly accumulates lipids, glycogen and protein. Starving conditions causes alterations both in the amount of reserves and in the digestive enzymatic activities. Point-of-no-return (PNR) is a threshold time at which initially starved individuals have lost their capability to recover from nutritional stress, even if they are later fed ad libitum. The aim of this study is to describe the enzymatic activities during a long period of starvation to understand the pattern of use of reserves nearby PNR. A total of 90 juveniles (mean weight 1g) were randomly assigned to one of two groups. Control juveniles were continuously fed while treated juveniles were fed since day 50, until the end of the experiment (day 90). Fifteen juveniles from each group were sacrificed at days 40, 50 and 90. Days 40 and 50 correspond to PNR25 and PNR50 , respectively. Protease, lipase and amylase activities of the hepatopancreas were estimated. Lipase activity from treated juveniles was lower than that of control juveniles during the starvation period, however, after feeding period the activity was similar between groups. Amylase and protease activities showed no significant differences between groups although protease activity tended to increase at day 50 and to diminish after the feeding period. Lipase activity suggests lipids use as the main energy source during long starvation period while protease increasing activity nearby day 50 could be causing the observed structural disorganization of the hepatopancreas.   Presenting author status: Faculty Preferred presentation type: Poster Language: Eng