Determination of dietary requirements of Acipenser persicus in the fingerling and grow-out stages (Stage one: Determination of optimum protein and energy in diet)

Growth experiments were conducted in a random statistical design to determine the dietary requirements of Persian sturgeon, Acipenser persicus. In this study the effects of various dietary protein and energy and their optimum P/E proportion in diets was estimated on growth and carcass composition in A. persicus in the fingerling and grow out stage in three different phases. In the first phase, 16 semi pure diets with 4 protein levels (35, 40, 45 and 50%), each with four energy levels (18.5, 19.8, 21.1 and 22.4 megjoules/kg diet) and P/E proportion of 15.63 to 26.4 mg protein KJ-1 were formulated and fed to 960 A. persicus fingerlings, with a mean weight of 10.26±0.11 for 112 days. Three replicates were used for each experiment group. In the second phase, 432 A. persicus juveniles with a mean weight of 112.25±1.187 g were fed 12 semi purified diets with 3 protein levels (40, 45 and 50%) each with 4 energy levels (18.5, 19.8, 21.1 and 22.4 megjoules/kg diet) and P/E proportion of 18.9 to 26.4 mg protein KJ-1 for a period of 101 days using three replicates for each treatment. In the third phase, 384 juvenile A. persicus with a mean weight of 803.26±3.5 g were fed 16 diets for a period of 140 days. Two replicates were used for each treatment group. At the end of the experiment 30% of the fish population was randomly selected for carcass analysis to determine protein, lipid, moisture and ash content. Hepatosomatic index of the fish specimens was also determined. In the fingerling stage the fish fed 45 and 50% protein with 22.4 megjoules/kg diet energy exhibited the best growth indices [final body weight, percentage body weight increase (BWI%) and specific growth rate (SGR)] (P0.05). A diet containing 40% protein and 22.4 megjoules/kg diet energy with P/E ratio of 17.86 mg protein KJ-1 is the recommended diet for A. persicus in this stage. In the first phase higher growth rates were observed in fish fed diets containing 40% protein as compared to those fed diets containing 45 and 50% protein. Increasing energy levels to 21.1 and 22.4 megjoules/kg diet significantly increased (P0.05) growth indices. Highest values for growth indices belonged to fish fed diets containing 40% protein, 22.4 megjoules/kg diet energy and P/E ratios of 17.86 mg protein KJ-1. Final weight, BWI% and SGR in fish fed diets containing 40% protein were higher as compared to fish fed diets containing 35, 45 and 50% protein. Increasing energy levels to 22.4 megjoules/kg diet resulted in significant increase in growth indices as well as P/E ratios. Highest growth indices were recorded with diets containing 40% protein, 22.4 megjoules/kg diet energy and a P/E ratio of 17.86 mg protein KJ-1. Results obtained indicate that A. persicus showed better growth rates after acclimation to formulated diets, and therefore can be considered a suitable species for culture in captivity. On the basis of growth rate and carcass composition diet containing 40% protein, 20.1 to 25.9% lipid with a P/E ratio of 17.86 mg protein KJ-1 prepared from good quality fishmeal, fish oil and vegetable oil (sunflower or soybean oil) is recommended for feeding A. persicus in the fingerling and grow out stages.