Effect of dietary protein level on spawning and egg quality of redclaw crayfish Cherax quadricarinatus

The effect of dietary protein level on spawning and egg quality was evaluated for female Cherax quadricarinatus. Diets containing four different levels of crude protein were evaluated (22, 27, 32, and 37%). After 100 days, no significant effects of protein level were found on survival (78.6-84.5%), final weight (41.0-43.1g), or fecundity (8.5-9.2 eggs/g female). The percentage of spawning females ranged from 19.7 to 27.3%, and a significant fit, using a quadratic equation estimated maximum spawning to occur at 30% crude protein. Significantly greater egg area (3.90 mm2), volume (39.3 mm3), weight (5.44 μg), and diameter (2.27 mm) were observed at 32% crude protein. There were no significant differences in mean egg protein (2227.1 ± 445.0 μg/egg), lipid (430.9 ± 85.2 μg/egg) and carbohydrate (73.9 ± 10.6 μg/egg) contents, and energy (13.3 ± 2.1 kcal/egg) in relation to dietary protein level. High statistical power indicated that biochemical composition was not affected by dietary protein level. We conclude that a dietary crude protein content of 32% is recommended for reproduction of female redclaw crayfish.