Comparison of Beluga (Huso huso) growth rate in brackish and fresh-water

Utilization of infertile coastal lands in the north Iran and Caspian Sea brackish water for reproduction and rearing of Beluga was the main objective of this study. To do so, 600 Huso huso fingerlings with an average weight of 4829 grams were reared in fiberglass tanks (1.9*1.9*0.53m), amounting to 25 fish per square meter. We used a random statistical design in two trials under similar conditions (feeding rate, stocking density etc.) over a rearing period of 80 days. Brackish water was transferred from the Caspian Sea and used in four tanks (Group I) and freshwater from the Sefidrood River was used in the remaining two tanks. Four replicates were used for experimental tanks and two were used for control tanks. Water flow in both groups was maintained at 0.2 to 0.5 liters per second. Results were analyzed statistically using one-way ANOVA and Duncan test. Mean water temperatures for brackish and freshwater treatments were 22.4±3.7 and 23.1±3/9 degrees centigrade respectively. Results of ANOVA on biometrical measurements during 71 rearing days indicated a significant difference in food conversion ratio (FCR) for the two treatments at 95% confidence level. After 71 days of rearing, FCR in Group 1 was 1.190.44, more suitable as compared to that in Group 2 (1.39±0.043). Fishes in Group 1 reached an average weight of 196.88 and those in Group 2 reached an average weight of 193.1g, indicating no significant difference in the final body weight of fishes in the two groups. Our observation showed better results for culture of Beluga in brackish water as compared to freshwater

Effects of dietary lysine and methionine supplementation on growth, nutrient utilization and carcass compositions in beluga, Huso huso, fed soy protein-based diet

A feeding trial was conducted to examine the effects of dietary supplementation of lysine and methionine on growth, nutrient utilization and carcass compositions in beluga, Huso huso. Four experimental soy protein based diets D0 (without lysine or methionine supplementation), D1 (lysine supplementation alone), D2 (methionine supplementation alone) and D3 (both lysine and methionine supplementation) were fed to triplicate groups. 240 fish with an average weight of 144.6 ± 4.64 g were fed the experimental diets for 12wk. L-Lysine and DL-methionine were added to the diets containing 344 g kg-1 soybean meals at 22.02 and 12.94 g kg-1 of dry diet respectively. Significant higher weight gain, specific growth rate, protein efficiency ratio, condition factor, feed efficiency ratio, whole muscle protein and protein apparent digestibility were observed in fish fed soya protein-based diet supplemented with both lysine and methionine than that of fish of other dietary groups. There were no significant differences among fish fed diet supplemented with either methionine or lysine. Growth performances, feed utilization, carcass composition and apparent digestibility coefficients of protein, lipid and dry matter of fish fed control diet was significantly lower than those of fish fed diet supplemented both lysine and methionine and supplemented with either methionine or lysine. It can be concluded that beluga, fingerlings effectively utilize the supplemental amino acids (L-Lysine at 22.02 g kg-1 dry diet and DL-methionine at 12.94 g kg-1 dry diet) in the diets containing 344 g kg-1 soybean meals for better carcass proximate compositions, growth performance and feed efficiency and utilization

Determination of the best stocking density for rearing Huso huso

Effects of stocking density on growth, food conversion ratio, specific growth rate, percentage of body weight increase in Huso huso were studied in two phases. Juveniles below one year old with an average weight of 92.09±1.72 grams and stocking densities of 1.6, 2.8 and 4 kg/m^2 in 3 replicates for 100 days were reared as the phase one group. One year old Huso huso with an average weight of 918.13±21.87 grams and stocking densities of 1.5, 2.5, 3.5 and 4.5 kg/m^2 reared for 120 days in 2000 liter fiberglass tanks were the second phase. Results revealed negative impact of density on growth, percentage of body weight, and specific growth rate and food conversion ratio in both phases. In the first phase, lower stocking density (1.6 kg/m^2) showed significant increase in growth rate (P<0.05) as compared to 2.8 and 4 kg/m^2 stocking densities resulting in 42.3% and 61 % growth rate respectively. Fish kept at 4 kg/m2 density showed malformed caudal fins and injured body due to higher tensions and contacts. In the second phase, the growth rate of fish decreased with increase in stocking density where fish with lower density (1.5 kg/m^2) showed 7.2%, 15.6%, and 19.8% higher weight gain as compared to fish reared at 2.5, 3.5 and 4 kg/m^2 stocking density. Analyses showed that with increase in stocking density, feeding area per fish decreases and tension between fish increases that leads to lower feeding efficiency. Based on the results, the recommended optimum stocking density for Huso huso individuals up to 90 grams is 1.5-2 kg/m^2 and for fish individuals over 900 grams each the density should be kept at 2.5-3 kg/m^2

Effect of different dietary protein and energy levels on growth of juvenile Beluga (Huso huso)

A 2 × 4 factorial design was conducted to study the effects of dietary protein and energy levels on growth performance of juvenile beluga (Huso huso) with average weight of 49.85 ± 1.64 g. Experiments were conducted with two dietary protein levels (40 and 45%) and four dietary energy level (18.5, 19.8, 21.1 and 22.4 MJ/kg diet) by ratio P/E (18.03 to 24.14 mg/kj). Fish were fed the experimental diets for 110 days. In each of the protein levels (40 and 45%), the feed efficiency, body weight increase, Protein efficiency ratio, specific growth rate, final body weight and total feed intake of fish improved significantly as dietary energy levels increased (P≤ 0.05). Growth of fish fed high- energy diets was significantly higher than those of fish fed low- energy diets at 40 and 45% dietary protein levels (P≤ 0.05). Protein content of carcass increased when dietary protein increased, but there was no significant different (P≥ 0.05) between 40 and 45 % protein. Lipid content of fish fed diet high- energy level was significantly higher than those of fish fed low dietary energy (P≤ 0.05). So the maximum growth and weight (22.4 ± 5.3 gr) was observed in treatment, that were fed diets containing 45% protein & 22.4 mega joule crude energy. Considering that no significant difference were affected for among the diet for the parameters studied, the diet containing 40 % protein, 21 % fat and 21.1 mega Joule crude energy per kilogram diet with a P/E ratio of 20 mg protein per kilo joule from a good quality source is a suitable diet in terms of physiology and economy can be considered a suitable diet to produce maximum growth in juvenile beluga in the weight class 49 to 200g

Effect of different dietary protein to energy ratios (P/E) on growth performance and body composition of farmed Persian sturgeon (Acipenser persicus)

To improve Persian sturgeon nutrition and determine its nutritional requirements, a growth trial was conducted to measure optimum dietary protein to energy ratio in Persian sturgeon sub-yearlings. Four diets: H (P/E=21.33mg/kJ), N (P/E=20.24mg/kJ), L (P/E=19.22 mg/kJ) and M (P/E=18.26mg/kJ) were used in the experiment. Triplicate groups of fish were kept in 500L fiberglass tanks under homogenous culture conditions (dissolved oxygen, light and water flow rate) and fed with the experimental diets. Fish were fed to satiation four times per day during 130 one fourth ¬ days of experiment when the average water temperature and dissolved oxygen were 12.82 plus or minus 1.48 degree C and 9.55 plus or minus 0.18 mg/l respectively. Fish in all treatments grew fast and efficiently utilized the diets. Growth rate, FE, GR, SGR and PER increased with decreasing dietary protein to energy ratios. A higher growth was observed in the fishes fed with lower P/E ratios. Food intake and fatness coefficient increased with increasing dietary energy and decreasing P/E ratios. There were no significant differences in feeding efficiency (FE) and protein efficiency ratio (PER) in fish fed with diet N (high carbohydrate and low lipid content) and diet L (low carbohydrate and high lipid content). We conclude that the Persian sturgeon is able to use lipids and carbohydrates as non-protein sources of energy. The results of the present study demonstrated that the protein content and P/E ratio for optimum growth and efficient protein utilization in Persian sturgeon is 40% and 18.3-19.2 mg protein/kJ energy, respectively

Determination of the best feeding ratio in Huso huso meat production cultured in fiber glass tanks

A two-phase random growth test was conducted to evaluate the effects of feeding rate on growth performance, food conversion ratio (FCR), specific growth rate (SGR), feeding efficiency and price index of reared Huso huso fingerlings in fiberglass tanks (2x2x0.53 cm). Rearing conditions such as diet, dissolved oxygen, light, water flow, fish density and feeding frequency were kept similar for the tanks. In the first phase, 180 fingerlings with a mean weight 867.86±17.42g were fed for 100 days in four treatments and three replications at feeding rates 1, 2, 3 and 4 percent of their biomass. In the second phase, also four treatments and three replications were applied to 84 Huso huso with a mean weight 2096.1±35.6g. In this phase, the fish were fed for 125 days with 0.75, I .5, 2.5 and 3 percent of their biomass. During rearing period, water temperature was 25.52±1.78 and 14.82±0.48 degrees centigrade and dissolved oxygen was 7.6±0.3 and 7.89±0.18 mg/lit, for the two phases respectively. The fishes were fed four times daily with a diet containing 40% protein, 13% fat and 9.9% ash. All treatments induced fast growth in the fish, but feeding ratios were different in their effects on the growth (P<0.05). Weight gain percentage, specific growth rate (SGR), food conversion ratio (FCR), feeding efficiency and price index indicated that lower feeding ratios were more effective in causing fish growth (P<0.05). So, increase in feeding ratio directly increased daily food consumption (D.F.C) and negatively affected the feeding efficiency, food conversion ratio, specific growth rate and price index (P<0.05). The results showed that in phase one, when the fish were given food as much as two percent of their body weight, one unit of meat was produced by consuming 1.92 units of food. In the second phase, feeding fish with 0.75 percent of their body weight resulted in producing one unit of fish meat per 1.82 units of food consumed. Also, in the two phases, application of higher than 50% feeding ratio increased costs while no significant trend in fish growth was detected. It can be concluded that regarding the water temperature, the optimal feeding rate for fishes weighing 850 to 1900 grams and those weighing 2050 to 3300 grams are 2 % and 1 % of body weight, respectively

Proximate composition and fatty acids profiles of Artemia cysts and nauplii from different geographical regions of Iran

Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p<0.05). The highest mean (±SD) level of protein (60.5±3.3%), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture

Effects of enriched daphnia with microscopic algae on some growth indices and survival rate of Persian sturgeon (Acipenser persicus) larvae

Microalgae as a source of valuable compounds such as fatty acids are isolated from the natural environments and their mass production with high nutritional value is one the necessities of many hatcheries. The present study aimed to determine the effects of enriched daphnia with microscopic algae on some growth indices and survival rate of Persian sturgeon (Acipenser persicus) larvae. Chlorella vulgaris and Scenedesmus dimorphus were purified and cultured. Then, Daphnia longispina was fed microalgae including Chlorella vulgaris and Scenedesmus dimorphus enriched with Docosahexaenoic acid (DHA). The microalgae density to enrich daphnia was estimated at 5× 107 cells mL-1. Three treatments with three replicates and a control group were considered in this study. A total of 30 Acipenser persicus larvae were allocated to each sixty liters tank. Experimental fish were fed daphnia enriched with Chlorella vulgaris (treatment 1), daphnia enriched with Scenedesmus dimorphus (treatment 2) and daphnia enriched with Chlorella vulgaris and Scenedesmus dimorphus (at the rates of 50%) (treatment 3). Persian sturgeon larvae in the control group were fed like VNIRO stage from daphnia caught in pond. Larvae were fed 30% of body weight per day for four times. During the experimental period, water temperature, dissolved oxygen concentration and pH ranged between 18-24°C, 5.8-7.2 mg l-1 and 5.6-8.2, respectively. The minimum (219 ± 98.4 mg) and maximum (315.16 ± 140.8 mg) mean (±SD) weights were observed in the control group and treatment 3, respectively. The results obtained from the body weight increase (BWI %) revealed that there were significant differences between treatment 3 and other treatments. Highest (4.6±1.13% day-1) and lowest (5.5±1.24% day-1) mean (±SD) specific growth rates (SGR) were recorded in fish fed the control group and treatment 3, respectively. Lowest (68%) and highest (85%) survival rates were recorded in the control group and treatment 3, respectively

Determining nutritional requirements in Beluga (H.huso) from larval stage to marketable size

Growth experiments were designed and conducted in several phases in order to determine the most suitable starter diet, to determine the effects of different levels of protein and energy and also to determine the effects of different ratios of carbohydrate to fat on growth and body composition in farmed Huso huso from the larval stage up to the marketing stage. Phase one Growth experiments were conducted in a random statistical design to compare growth trends in H. huso larvae (mean weight 105.02 ± 0,02 mg) without being adapted to formulated diets. Experiments were conducted in fibreglass tanks (500 litre capacity) under similar culture conditions. Four replicates were run for each experiment. Larvae were fed four types of formulated diets (Diet A=100 % formulated diet produced in the International sturgeon Research Institute, Diet B=formulated diet imported from Holland, Diet C= formulated diet imported from France, Diet D= a mixture of Diet A + 10% gammarus) 8 times a day to satiation for a period of 49 days. The results obtained were compared with those obtained for the control group that was fed live food (Daphnia and Artemia). Mean water temperature during the experimental period was 18.52 ± 0.48 °C and mean dissolved oxygen was 7.35 ± 0.18 mg/l. The first signs of food granules were observed in the guts of the larvae after 12 h of the first feeding. All experimental groups were adapted to granulated diets on day 3 to day 5. In the beginning of the experimental period the larvae showed a no normal distribution (P 0.05) in terms of weight and length. However significant differences were observed in the end of the experimental period among the different groups studied in terms of growth, specific growth rate and food efficiency (P 0.05). Growth in group B and D were significantly higher than that in other groups except for the control group (P 0.05). It may thus be concluded that the olfactory organs of larvae took to Diet B (may be due to its composition) and to the diet D (because of its odour, texture and suitable flavour) more readily than other diets. At the end of the experimental period, maximum survival (98%) belonged to the control group. Survival rate in Group B and Group D was 90 % and 86.5%, respectively (P 0.05). Minimum survival belonged to fish fed Diet A (29.7%) and Diet C (45.5%). With regard to the adaptability of larvae to formulated diets, survival rates and growth and development in larvae we may conclude that the effects of different formulated diets on growth in larvae can be conducted on larvae with a mean body weight between 100 to 120 mg. In this weight class the digestive system and olfactory organ are fully developed and play a vital role in searching for food particles