forouzan bagherzadeh lakani

Excessive use of synthetic drugs brings numerous disadvantages for the environment and health, so the need to formulate alternative strategies in the management of fish diseases in aquaculture increases. Studies show that both Allium sativum and Echinacea purpurea have antioxidant properties that can increase the activity of antioxidant enzymes in fish. So, this study was performed to evaluate the effects of two types of powdered extract Echinacea and garlic on antioxidant capacity of farmed beluga Huso huso during a two-month period.

A total of 210 fish with an average weight of 27.74 ± 0.26 g were randomly placed in twenty one 500-L fiberglass tanks, and fed with basal diet supplemented with powder extracts in seven treatments (with three replications) including control (without adding garlic and E. purpurea), treatment 1 = 250 mg/kg garlic, treatment 2 = 500 mg/kg garlic, treatment 3 = 1000 mg/kg garlic, treatment 4 = 250 mg/kg E. purpurea, treatment 5 = 500 mg/kg E. purpurea, treatment 6 = 1000 mg/kg E. purpurea for 8 weeks. At the end of experiment, the amount of catalase, GPX, SOD and MDA enzymes was measured in six fish per treatment.

The results showed that the amount of catalase, SOD and MDA in the blood serum in the treatments increased compared to the control. The catalase level in treatment 5 was significantly higher than in the other treatments, while the lowest in control and treatment 1. The SOD levels in treatments 2, 3, 5 and 6 were significantly higher than in the others, while the lowest amount in the control. The amount of MDA in treatments 3, 5 and 6 was significantly higher than in others, while the lowest in the control. The GPX levels in fish blood serum in treatments 6, 5 and 4 were significantly higher than in the others, while the lowest in treatments 1, 2 and 3.

The result showed that supplementation of 1000 mg/kg Echinacea purpurea powder extract is more effective in improving antioxidant capacity in reared beluga.

This study aimed to investigate the effects of different levels of selenium nanoparticles (Se-NPs) and iron nanoparticles (Fe-NPs) on histopathology of the liver in the beluga juvenile, Huso huso. A total of 135 beluga juveniles (with initial weight of 276.4 ± 32.3 g and initial length of 40.0 ± 2.0 cm) were randomly distributed in 27 fiberglass tanks at 9 different treatments with three replicates. Treatments included T1 (control, no added NPs); T2 (1 mg/kg Se-NPs); T3 (2 mg/kg Se-NPs); T4 (100 mg/kg Fe-NPs); T5 (100 mg/kg Fe-NPs + 1 mg/kg Se-NPs); T6 (100 mg/kg Fe-NPs +2 mg/kg Se-NPs); T7 (200 mg/kg Fe-NPs); T8 (200 mg/kg Fe-NPs +1 mg/kg Se-NPs); T9 (200 mg/kg Fe-NPs +2 mg/kg Se-NPs). Before starting the experiment, the fish were adapted to the rearing conditions for one week. The amount of feeding during the rearing period was 2-3% based on the weight and water temperature, and the fish were fed three times a day (8:00, 15:00 and 21:00) for 8 weeks. In order to find the histopathological changes, the livers of six fish from each group (two fish of each replicate) were sampled at the end of the experiment. Samples were dehydrated by routine methods and embedded in paraffin wax. They were sectioned by microtome and stained with H & E. Vacuolar degeneration, necrosis, inflammation, irregular hepatocytes and hemorrhage were the tissue lesions observed in the liver. Given that, T5 (100 mg/kg Fe-NPs + 1 mg/kg Se-NPs) had the lowest liver tissue damage, using 1 mg selenium nanoparticles with 100 mg iron nanoparticles in the diet of farmed beluga is recommended.

This study was performed to evaluate the effects of two types of powdered extract Echinacea purpurea and Allium sativum on growth indices and survival rate of Huso huso during a two-month period. For this purpose, 210 juvenile with an average weight of 27.74 ± 0.26 g were randomly placed in 21 half-ton fiberglass tanks in seven different treatments with three replications, including a control group and three experimental groups of different amounts of E. purpurea powder extract (T1, T2 and T3: 250, 500 and 1000 mg kg-1) and three experimental groups of different amounts of garlic powder extract (T4, T5 and T6: 250, 500 and 1000 mg kg-1). At the end of the experiment, a statistically significant difference was observed between the treatments in the mean final weight, mean final length, final biomass, final production, fish weight gain, mean daily growth, body weight gain increase, specific growth rate and daily growth rate (p<0.05). These indices in the treatments had an increasing trend compared to the control and in T6 (1000 mg of E. purpurea powder extract per kg of food) which was significantly higher than in the other treatments (p<0.05). The feed conversion ratio in this treatment was also decreased significantly compared to other treatments (p<0.05). There was a significant difference in levels of ALP and LDH enzymes between treatments and control group (p<0.05). The highest level of ALP enzyme was in control group and T6, while the lowest level was in T4 (250 mg of E. purpurea powder extract per kg of food) (p<0.05). The highest level of LDH enzyme was observed in the control group and T6, however, the levels of ALT and AST enzymes were not significantly different between treatments and control group (p>0.05). The results showed that addition of 1000 mg turmeric powder extract per kg of food is more effective in improving growth indices.

The analysis of blood parameters is a useful indicator in assessing the physiological conditions of aquatic animals in response to stress, pollutants, nutrition, and also physiological and ecological changes. In this study, some hematological parameters of Acipenser persicus in three age classes including cultured fingerlings, juveniles and broodstocks were studied in a six-month period (spring and summer 2012). The counts of red blood cells (RBC), white blood cells (WBC), hematocrit (PCV), hemoglobin (Hb), MCV, MCH, MCHC, electrolyte and non-electrolyte biochemical parameters, and also differential leucocyte count were measured in different age classes. For this reason, 30 Persian sturgeon(10 fingerlings, 10 juveniles, 5 males and 5 females) were used. Statistical results showed significant differences in Hb, RBC, MCV, MCHC, WBC, lymphocyte (%), neutrophil (%) and eosinophil (%) in different age classes of this species (P<0.05). There were significant differences in non-electrolyte biochemical parameters such as glucose, albumin, total protein, triglyceride, cholesterol, osmolality and total lipid at different ages (P<0.05). Significant differences were observed in electrolyte biochemical parameters including sodium and chloride ions at different age classes and also at females and males. It was also true for calcium and potassium ions at different ages (P<0.05). Based on the results, it can be concluded that the hematological and biochemical parameters are affected by age and sex of fish although the effects of environmental and nutritional parameters are inevitable.

Sturgeons are of commercially important fish species in the Caspian Sea, but there are few reports about their oxygen requirements. In the present study, the effect of different oxygen levels on hematological parameters were examined in two weight classes of great sturgeon Huso huso including small size (average initial weight 280.9 ± 49.2 g) and large size (average initial weight 1217.9 ± 138.1 g). Oxygen treatments including Hypoxia (2-3 mg/l), Normoxia (5-6 mg/l) and Hyperoxia (9-10 mg/l) were set up with managing inflowing water and using system equipped with oxygen enriching for Hyperoxygenation (pure oxygen injected). Fish were acclimated to experimental tanks for one week and then randomly were transferred to 9 tanks for each class (3 fish per tank in higher weight class and 6 fish per tank for lower one) and were kept for 8 weeks. HCT and MCHC at lower weight class and RBC, MCV and Neutrophil at higher weight class were significantly different between treatments.

The aim of the present study was to evaluate dissolved oxygen concentration on growth and muscle composition of great sturgeon, Huso huso, in two weight groups (initial weight 280.9±49.2 and 1217.9±138.1). Oxygen treatments including hypoxia (2-3 mg/l), normoxia (5-6 mg/l) and hyperoxia (9-10 mg/l) were prepared by adjusting inflowing water and utilizing equipments for providing hyperoxygenation (pure oxygen injection). Fish were acclimated to experimental tank for one week and each group were randomly distributed in 9 tanks (3 fish per tank in higher weight group and 6 fish per tank for lower one) for 8 weeks. There were significant differences between treatments for Wt, WG, BWI, FI and SGR in both groups and CF in higher weight group (P<0.05). Muscle composition analysis showed no significant differences among the treatments in lower weight group (P>0.05) but moisture and fat content showed significant differences between treatments in higher weight group (P<0.05). Results indicated that high oxygen level has a direct effect on growth performance of great sturgeon and hence the use of a high oxygen level is recommended for the culture of great sturgeon.