An investigation of the effects of differing protein levels on growth indices WG, RGR, FCR, FCE and PER in cultured crayfish (Astacus leptodactylus)

Knowledge of nutritional requirements and especially protein levels is needed to produce strong and larger freshwater crayfish in controlled conditions. This has not been available for the miniature size crayfish culture. Hence, an eight-week experiment was conducted on miniature size crayfish in three treatment groups each with three replicates receiving a diet that contained 25%, 30% and 35% protein levels with isocaloric digestible energy (DE) 3500 kcal/kg. A number of 540 miniature crayfish with a mean weight 100± 12mg were randomly selected and partitioned into nine tanks containing 200 liters of freshwater 70% of which exchanged daily. The fish were fed at 25% of body weight five times daily at 6, 10, 14, 18 and 22 hours using pellets 0.1, 0.2 and 0.4 mm. Nutritional responses in tern of weight gain, PGR, FCR, FCE and PER were compared among the groups using one-way ANOVA. The test showed a significant increase in the indices such as WG and PER in response to increased protein level (P<0.05).
FCR, FCE and PGR show a significant increase using 20% protein level while using 30 and 35% protein levels did not produce significant results (P<0.05). The test revealed a significant difference between treatments 1 and 3 (P<0.05) but not between 1 and 2.1 conclude that the treatment 3 produces more reliable results.