Optimal stocking density for beluga, Huso huso, and ship sturgeon, Acipenser nudiventris during the grow‐out phase

The influence of three different initial stocking densities (SD) in flowthrough systems was evaluated on growth performance and feed utilizaition in beluga, Huso huso, and ship sturgeon, Acipenser nudiventris, juveniles in three different grow‐out phases for 228 days. In each grow‐out phase, fish were randomly distributed in 18 concrete square tanks (2.0 × 1.0 × 1.2 m3; 2 m3 of volume) according to the experimental SD. At the first phase, both fish species were subjected to three SD including 1.5, 3 and 6 kg/m2 for 60 days. In the second phase, fish were submitted to three SD including 3, 6 and 9 kg/m2, whereas in the third phase, beluga were stocked at 6, 9 and 12 kg/m2 and ship sturgeon were stocked at 6, 8 and 10 kg/m2 and each phase lasted for 12 weeks. In both species, the growth performance and feed intake (FI) significantly decreased with increasing SD at the end of the first phase (p < 0.05). In the second phase, growth performance and FI in beluga decreased with increasing SD, whereas in ship sturgeon neither growth nor FI were affected by SD. Interestingly, the growth performance and feed utilization in both species were not decreased with increasing SD in the third phase indicating adaptability of these species to high stocking density during grow‐out period. According to the result of this study, the appropriate initial SD for beluga within the range of 100–500, 500–2,000 and 1,500–3,000 g were at 1.5, 6 and 12 kg/m2, respectively in an open flow‐throw system. Regarding to ship sturgeon, initial SD at 1.5 and 10 kg/m2recommended for fish within the range of 100–300 and 300–1,200 g, respectively in an open flow‐throw system.info:eu-repo/semantics/acceptedVersio

The survey of possibility of beluga (Huso huso) sturgeon culture in different densities in Khuzestan province

The influence of stocking density was investigated on growth, survival and FCR of great sturgeon (Huso huso) juvenile in north of Khuzestan province (Dezful). The study was conducted by Southern Iran Aquaculture research center. This study was done from September 2013 to July 2014 in three stage with different weight of Huso huso juveniles. In the first stage density of 1.5, 3 and 6 kg/m^2 during two month was performed. The initial weight and length of fish in this stage considered as 143±0.29 g and 316±1.1 mm. In the second stage 3, 6 and 9 kg/m2 density were introduced. The initial weight and length of fish in this stage considered as 548.58±33.26 g and 416.5±0.81 mm and duration of the stage was 84 days. In the third stage 6, 9 and 12 kg/m^2 density were introduced and initial weight and length were 1571.33±71.33 g and 687.5±10.96 mm. Growth and feeding index were assess in each stage. In the first stage monthly blood samples were collected from each density. In this stage bold and hormonal indices were assessed. The results showed that the average final weight in stage 1 in 1.5, 3 and 6 kg/m^2 densities were 527.27±6.82 g, 467.91±18.81 g and 431.02±24.25 g respectively. The highest average of weight was in treatment 1 and it has significant difference with treatment 3 (P0.05). FCR, condition factor, daily growth, special growth index, BWI and food performance index have not significant difference in treatments. Daily growth rate in treatment 1, 2 and 3 were 13.93±2.83, 11.44±2.65 and 9.6±2.49 respectively. In the third stage the average final weight in 6, 9 and 12 kg/m^2 densities were 3232.22±66.12g, 3407.39±119.73g and 2869.72±135.7g. The highest average weight was in treatment 2 and has significant difference with treatment 3 (P0.05). FCR, condition factor, daily growth, special growth index, BWI and food performance index have not significant difference in treatments. Daily growth rate in treatment 1, 2 and 3 were 20.37±3.12 g/day, 19.90±4.2 g/day and 16.36±3.64 g/day respectively

Digestive function and serum biochemical parameters of juvenile Cyprinus carpio in response to substitution of dietary soybean meal with sesame seed (Sesamum indicum) cake

A feeding trial was designed to evaluate effects of soybean meal replacement (SBM) with sesame seed cake (SSC) at 0 (SSC0), 25 (SSC25), 50 (SSC50), 75 (SSC75), and 100 (SSC100) % in isoproteic (30%) and isolipidic (8%) diets on the growth performance, digestive function and serum and hematological parameters in Cyprinus carpio. Four hundred and fifty common carp juveniles (83.09 g) were randomly distributed into 15 tanks with a flow-through system. Triplicate groups of fish were hand-fed one of the diets to visual satiation thrice daily for 90 days. The survival rate, growth performance and somatic indices did not show significant differences between treatments. Among feed utilization indicators, nitrogen retention efficiency was significantly higher in SSC25 than in other treatments. Lipid retention efficiency significantly increased from SSC50 to SSC100. The number of white blood cells was significantly higher in SSC0 than other treatments. Significantly higher hemoglobin was observed in SSC75 as compared to SS0 and SSC25. Serum biochemical parameters did not significantly differ between dietary treatments. Dietary SSC resulted in significant increase in calcium ADC and activity of digestive trypsin, chymotrypsin, lipase, α-amylase, and alkaline phosphatase. Significantly higher villi height and intestinal muscle layer width were observed in fish fed the SSC75 diet. The villi width in SSC25 and SSC50 was significantly less than in SSC0. Comparable growth performance, feed utilization, apparent digestibility, digestive function, hematological and serum factors indicated the possibility of 75–100% substitution of SBM by SSC in the diet of juvenile C. carpio