فهرست مطالب valiallah jafari

In order to survey the effect of Thyme (Thymus vulgaris) extract on the common carp , 180 fish with the average weight of 10.84±0.063 were randomly divided into four groups (with Thyme extract added in 0, 0.5, 1 and 2 % to the fish diet) in three replicates (each with 15 fish) for 70 days. At the end of this period, 30 fish from each group were exposed to the seawater with 13 and 14 ppt for 12 hours to survey biochemical parameters and survival rate and resistance, respectively. In this regard, blood samples were collected before salinity stress and 6, 24, 72 and 168 hours after salinity stress. Our results showed that added Thyme supplement into the food has no effect on fish resistance during the experimental period (P>0.05). Cortisol, glucose, total protein, albumin showed no significant differences between treatments before salinity stress (P> 0.05). However, increasing salinity increased cortisol and glucose significantly in all treatments compared to pre-salinity stress (P <0.05). Albumin and total protein did not show any significant difference in any treatments (P >0.05). Based on the results of the present study, adding thyme extract at 0.5, 1 and 2% into the diet did not have any effect on fish resistance and blood biochemical parameters of the common carp exposed to the salinity stress.

Olfaction is one of the fundamental senses to detect odors from long distances in sturgeons, and it plays an important role in feeding behavior and orientation fish. This sense can be a reliable criteria to investigate the effect of pollutants on aquatic organisms. Therefore, the main objective of this study was to evaluate effects of silver nanoparticles on olfactory feeding behavior of Persian sturgeon. This behavior was investigated following exposure to 0.01, 0.005 and 0.001 mg L-1 AgNPs for 7 days (each group with 3 replicates) and 6 amino acids were used to evaluate the olfactory behavior. During the course of the experiment, solution containing amino acids was introduced into the aquarium for 3 min. Then the number of fish and their behavior was counted every30 sec after the start of each trial. The results showed that the concentration of 0.01 mg L-1 AgNPs significantly reduced the olfactory attractiveness of alanine, glycine and leucine amino acids. Also, olfactory behavior responses were significantly reduced only at a concentration of 0.01 mg / L. but responses to the repellant amino acids (tyrosine, aspartic acid and glutamic acid) were not significantly different in none of the concentrations of silver nanoparticles.

Arginine is one of the amino acids that its impact on improving the growth and immune system of human and many animals always been one of interest of researchers. In this study, the effect of this amino acid on growth indices and resistance against salinity tension on common carp fish has been investigated. For this purpose, four treatments (each treatment with three replicates) were made from common carp and fed with dietary foods containing arginine 0, 1.5, 2 and 2.5% for 60 days. During this period, the fishes three times were biometrics. Data analysis was performed using SPSS software version 18 and Excel and the comparing the mean of treatments in a completely randomized design have been performed analysis with Duncan test and one way ANOVA and existent or lack significant difference were performed in 5% of the level Probability (P<0.05). Regarding to the results obtain from arginine acid on food conversion rate (FCR), body weight gain and percentage of body weight gain of carp, it had significant impact (P <0.05), however, increasing body weight gain and decreasing FCR were observed in treatment groups (P<0.05), however condition factor (CF), growth specific rate (SGR) and survival rate (SR), did not showed any significant difference (P>0.05). Therefore, according to the present results, applying of salinity stress on different treatments showed that the presence of arginine in the feed of carp fish may have a significant effect on their resistance and survival, so that for feed treatments with 1.5% and 2% of arginine within 72 hours did not show any casualties, therefore. Hence, according to the present results, use of 2% L-Arginine to increase weight of carp, recommended.

The aim of this study was to determine the effects of amino acid glycine on growth indices, survival rate, food intake and resistance to salinity stress in Common carp (Cyprinus carpio</em>) fingerlings. Fish with an average weight of 15.46±0.18 gr were devided in to four groups and fed with different levels of glycine including diets containing 0 (control), 0.5 (treatment 1), 1 (treatment 2) and 1.5 (treatment 3) of glycine were fed for 60 days and then exposured to salinity stress 15 ppt for 72 houres. The experimental design was a complete randomized data analysis performed SPSS and Excel software package. The results showed that there was no significant difference among studied groups regarding growth indices (final weight, SGR, CF and FCR) (P>0.05). Body weight gain affected significantly by glycine (P<0.05). The addition of glycine to the diet increases observed in survival and resistance to stress salinity in common carp. Hence according to the results obtainer of present study, it can be concluded that the glycine improved the resistance can increase survival of common carp under salinity stress.

In the present study pathogenicity of Yersinia ruckeri have been studied in common carp, Cyprinus carpio, fingerlings. In this regard, 120 common carp fingerlings with average weight of 13 ± 2 divided into 10 aquariums (12 fish per aquaria) and were reared for 28 for acclimatization. In this study one control and 4 treatment groups (with two replicates for each one) were considered. Fish of treatment groups were challenged with Yersinia ruckeri via intra peritoneal injections at dosage of 5.4×108, 5.4×107 , 5.4×106, 5.4×105cells/fish. Control fish just received sterile normal saline (0.9% NaCl) via intra peritoneal injection. According to the results mean lethal concentration (LC50) of this bacterium after 7 days and until 21 days post challenge calculated as 2.8 ×108 cell/fish. Congestion in internal organs especially in kidney and accumulation of bloody fluid in the abdominal cavity were the most clinical signs in sick fish. Gill histopathology was characterized by hyperplasia and epithelial lifting in secondary lamella, kidney histopathology was characterized by congestion and bleeding in interstitial tissue, accumulation of fluid in tubular lumens and tubule necrosis and so in the liver congestion and hepatocyte necrosis were recorded as the most histological signs

Today, the use of natural immunostimulant such as medical plants has been growing in aquaculture an alternative of chemicals and antibiotics in control of fish disease. The present study was done to investigate the effects of Urtica dioica hydroalkohalic extract on some hematological parameters (white and red blood cell count, hemoglobin, hematocrit, MCHC, MCV and MCH) and biochemical indices (glucose, cholesterol, albumin and total protein) in Carassius auratus. For this purpose, fish with an average weight of 21.88 ± 4.7gr divided in 3 treated groups, fed 2, 4 and 8 g/kg of Urtica dioica supplementation and the control group in 2 replicates (7 treatments with 2 replicates). According to the result no significant differences were revealed in hemoglobin, hematocrite, MCH, MCHC and MCV in fish fed supplementation of these extracts (p>0.05). Albumin showed a significant increase in fish fed 4g/kg Urtica dioica compare to control and other groups. Glucose, Cholesterol and triglyceride levels didn’t show significant differences in fish fed extracts compare to control (p>0.05). It appears that supplementation of diet with Urtica dioica could improve physiologic parameters in Carassius auratus.

Apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), essential amino acids (EAA), non-essential amino acids (NEAA) and fatty acids were determined for whites shrimp (Litopenaeus vannamei). Shrimp (weight average 0.25gr) was feed in sex treatment and 18 tanks during 8 weeks it was including T1 (300 individual/m2, 1×1010 cfu/gfood) and T3 (250 individual/m2, 1×1010 cfu/g food), T2 (300 individual/m2, 1010 cfu/gfood), T4 (250 individual/m2, 4×1010 cfu/g food) and control group (C1 300 individual/m2, C2 250 individual/m2). Apparent digestibility coe⁄cients was determined using OF 0.03% Y2O3 as an indicator. In all treatment digestibility of T2 (300 individual/m2, 4×1010 cfu/gfood) and T4 (250 individual/m2, 4×1010 cfu/g food) exception (ADCs) of dry mater showed significant increasing to control groups (p<0.05). Apparent digestibility coefficients ADCs of diets T1 (300 individual/m2, 1×1010 cfu/gfood) and T3 (250 individual/m2, 1×1010 cfu/g food) didn’t show increasing different to control groups (p>0/05). But, Apparent digestibility coefficients of ash and amino acids showed significant different between all treatment including (T1, T3) (T2, T4) and control groups (p<0/05). In all groups, highest digestibility was belong amino acids, it was showed highest increasing to another factors. Probiotcs effect on density in all treatment did not show significant difference (p>0.05).