Variation in lipid, protein, and carbohydrate content during the embryonic development of the crayfish Cherax quadricarinatus (Decapoda: Parastacidae)

Abstract

Eggs of 20 females were sampled to analyze lipid, protein, and carbohydrate content during the embryonic development of Cherax quadricarinatus. Sampling was performed on recently spawned eggs to first juvenile stage. Ten eggs were sampled every 48 h during the first two weeks and every 72 h thereafter for biochemical analysis. Total proteins, lipids, and carbohydrates were measured. Proteins were the most abundant egg component (63.2%), followed by lipids (32.3%), and carbohydrates (4.4%). A steady decrease of lipid content was observed (y = 895.38 - 9.93x, r2 = 0.94; y = lipid concentration, x = days). For proteins, two different depletion rates were observed, with the initial rate maintained for 30 days (y1 = 1,443.0 - 4.46x1, r2 = 0.90) and an increased depletion rate after hatching (Y2 = 1,936.60 -21.10x2, r2 = 0.96). Carbohydrates were always present as a minor constituent, and its concentration did not change significantly. Water content increased from 52% in recently spawned egg to 85% in juveniles. Energy equivalents were calculated from each component, and the overall energy expenditure is represented by the equation y = 13.86 - 0.11x (r2 = 0.95). Relevant morphological features for each sample day are indicated.