Proposal of a practical diet for juvenile astacid crayfish studies from the onset of exogenous feeding under controlled conditions

Abstract

Considering the knowledge on freshwater crayfish feeding requirements and other cultured crustaceans, a practical extruded diet was formulated with the aim to be used for juvenile astacid studies from the onset of exogenous feeding. According to a bifactorial design, the practical diet was compared with the diet which has allowed repeated good survival and growth results (control: feedstuff for trout combined with Artemia cysts) in groups and individually isolated crayfish in an 80-day experiment. Diets tested did not affect final survival rates and growth neither in grouped nor in isolated crayfish, being the highest survival rate (average: 93%) and growth values (average: 13.2 mm carapace length: CL, 578.1 mg weight: W, 3.52%·d-1 specific growth rate: SGR, 1896.6% weight gain: WG) reached with the practical diet. Survival rates did not show significant differences neither among crayfish maintained in groups (86% for the practical diet and 81.7% for the control diet) nor among isolated crayfish (100% survival). Isolated crayfish had significantly higher growth (14.3 mm CL, 760 mg W) than the grouped crayfish (11.5 mm CL, 354 mg W). Results show the feasibility of the proposed practical diet as basis for further studies on astacid crayfish. © 2011 ONEMA.