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In this study the effect of iron of Fe (So₄)₂ (7H₂O( and probiotics BioPlus 2B on some blood parameters was investigated on 270 of Rutilus frisii kutum fry with total weight of 0.4±0.1 gr and total length of 3.9±0.3 cm  in nine treatments and triplicates during 60 days. Results showed that the highest number of red blood cells (RBCs) (1.65×10⁶± 1.55 per mm³⁾, hemoglobin concentration (7.36±0.15 g/dl), hematocrit concentration (24.03±0.85 %), MCV (1.45±1.48 Fl), MCH (46.29±0.25 pg) and lymphocyte (92±2) belong to treatment 5. The highest level of MCHC (34.65±0.67 g/dl) and the greatest level of white blood cells (6.6±100 per mm³) were observed in treatments 4 and 8, respectively. The findings of this research showed that treatment 5 contained the highest amount of iron (7 mg/kg of feed) and probiotics (CFC 1.6×10⁹) resulted in the highest amount of red blood cells, hemoglobin, hematocrit, MCV, MCH and lymphocytes in this study.

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Cortisol is a corticosteroid hormon which has important effects on osmoregulation in marine fish. In this study the effect of oral cortisol on resistance (salinity stress in 12ppt during 7 days) in common carp (cyprinus carpio) fry was investigated. For this purpose, common carp (1.36±0.12 gr) was distributed in 3 treatments and 1 control group in 3 replicates and fed with commercial food containing 0 (control), 50, 100 and 200 mg kg^-1 food hydrocortisone during 8 weeks. At the end of the trial, hematocrit, biochemical blood parameters (glucose, calcium and total protein) and resistance of fish were determined. The results showed no significance in survival rates between treatments (p>0.05). Glucose levels in the control treatment was significantly lower than other treatments at the end of the trail by serological investigation (p<0.05). Fish were let in salinity stress and after 7 days all treatments showed a significant increase in the value of glucose (p<0.05). The highest value of glucose was observed in fish on fed 100 and 200mg hydrocortisone per kg^-1 food )73.04±1.40) (p<0.05) and the highest level of haematocrit was observed after stress in the control group (61.67±2.08) (p<0.05). Calcium Ionic factor showed a significant increase in all treatments except for the control treatment (11.17±0.31) (p<0.05) and the highest value was observed in fish fed 200 mg hydrocortisone per kg^-1. Total protein in fish treat-cortisol was significantly lower than the control group (p<0.05). The results of this study showed that oral administration of cortisol can improve the salinity resistance in the common carp fry

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This study was carried out to show the effects of herbal supplement of Sangrovit on the growth parameters, blood biochemical factors, survival and resistance to salinity of the Caspian kutum fry. Fish (1±0.003 g) were divided into four groups fed on diets containing sangrovit at different levels: 0 (control), 0.05, 0.1 and 0.15 % for 45 days. The results showed that there was a significant increase in the final weight, weight gain and specific growth rate of the fish fed on sangrovit diets (p<0.05). In addition, food conversion rate of fish fed on sangrovit diet was found to be significantly (p<0.05) lower than the control group. However, there was no significant difference in the condition factor, glucose and total protein levels of the experimental groups and the control group (p>0.05). On the other hand, blood cholesterol of the Caspian kutum was significantly increased in the control group (190.17±0.013 mg dl^-1) in comparison to treatments sangrovit (p<0.05). Survival and resistance to salinity stress remained unaffected by dietary supplementation of sangrovit (p>0.05). The results of the present study also indicated that dietary Primalac beneficially affected the growth performance and blood biochemical parameters of the Caspian kutum fry. The findings of the present study indicated that the herbal supplement of sangrovit could improve the growth rate, feed utilization and blood biochemical parameters of the Caspian kutum fry.

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In the research project performed, the effects of different levels of hydro-alcoholic extract Vitex agnus-castus were investigated as nutritional supplement on growth parameters of Danio rerio for 4 months. Since the beginning of the feeding phase up to the age of 4 months (average weight: 2.1±0.1g, length: 5.2±0.3 cm), larvae were fed with expe-rimental diets. Fish treated with diets containing plant extracts had higher growth and survival rate than the control gr-oup (p<0.05). Differences in the level of the extract had no significant effect on the survival rate (p<0.05). The results revealed that the diet containing 15 gr of the extract resulted in the best FCR significantly (p<0.05). By increasing the extract in the diet during the experiment, SGR increased. The highest and the lowest %BWG were observed in treatm-ents T3 and T0 respectively (p<0.05). The highest CF was observed in T3 and the lowest was obtained in T0. All in all, this study proposed that the addition of 15 gr of hydro-alcoholic extract of Vitex agnus-castus in the diet of zebrafish could improve the performance of the growth indices and increase the final biomass. In addition, this extract could be considered as a suitable supplement for Cyprinidae diet.

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Feeding frequency and stocking density are important factors affecting growth and maturation of cultured fishes. The aims of this investigation were to determine the effects of stocking density (10, 20, 30 and 40 fish per aquarium) and feeding frequency (2, 3 and 4 times per day) on growth parameters and hematocrit of the Rutilus rutilus caspicus. The experiment was continued for 45 days in two replicates. The results of this study showed that growth parameters, including weigh gain (WG), feed conversion ratio (FCR) and specific growth rate (SGR) were affected significantly by stocking density (P<0.05), but not significantly affected by feeding frequency (P>0.05). The highest WG and SGR were recorded with the lowest stocking density (10 fish / aquarium). The least FCR was obtained in density of 10 fish/aquarium, FCR value was significantly higher with high stocking density (P<0.05). Also, interactions between stocking density and feeding frequency were no significant on growth parameters (P>0.05). Density and feeding frequency hand no significant effect of hematocrit concentration (P>0.05). On the other hand, interactions between stocking density and feeding frequency significantly affected hematocrit levels (P<0.05). The lowest level of hematocrit was observed in density of 10 fish/aquarium at two times / day feeding frequency. The results of this study indicated that density is significantly affected the growth, but increasing of feeding frequency there is not effect on growth in the Rutilus rutilus caspicus.
 

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Sex steroid hormones play important roles in many physiological processes, particularly in the reproduction of teleostei. Therefore, study of steroid hormones in fish is one of the important indicators of reproductive biology. In the present research, serum steroid hormones such as testosterone (T), 17β-estradiol (E2) and progesterone (P) in Esox lucius brood stocks, during one year, from autumn 2010 to summer 2011, in five periods (autumn, first half of winter, second half of winter, spring and summer) with three longitudinal classes: 300-360, 360-420 and 420-480 millimeters were studied. The results showed significant difference between levels of steroid hormones in three longitudinal classes and showed an increasing trend by increased length (P<0.05). In addition, there was significant different between levels of gonadal steroid hormones and different seasons (P<0.05). The highest level of 17-β estradiol was observed in autumn season. In the case of testosterone and progesterone hormones, higher levels were recorded in first and second half of winter, respectively.
 

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Algae are the most important group of organisms which considerably affect the water quality. Although algae constitute one of the fundamental parts of the aquatic food chains, only few researches deal with the freshwater algae of Iran. Filamentous algae are important components of the river vegetation. The Balikhlou River is utilized as a source to obtain drinking water for the city of Ardabil, therefore, the algae flora of this river was studied and a total number of 18 taxa of filamentous algae were determined, of which nine species were belonged to the Cyanophyceae class of Cyanobacteriae, while five speciesof which were belonged to the Chlorophyta. In addition, four species were recorded for the first time from Iran, i.e., Audouinella eugenea, Arthrospira gigantea, Homoeothrix janthina and Tychonema bourrellyi.