فصلنامه آبزیان و شیلات
پیاپی 17 (بهار 1393)

This study was carried out to extract total lipid of ( Encrasicholina punctifer )and ( Dussumieria acuta ) caught from northern coast of the Oman Sea (Iran). Fatty acid composition was determined by capillary gas chromatography. The results show both species to be rich in palmitic acid (C16:0) and cis-oleic acid (C18:1n9c) of saturated (SFA) and monounsaturated fatty acids (MUFA), respectively. However, the main polyunsaturated fatty acids (PUFA) in the two species were DHA and EPA respectively. The results of this study showed the high content of fatty acids, specially (ω3) series in E n c r a s i c h o li n a p u n c ti f e r and D u s s u mi e r i a a c u t a . Their PUFA profiles are complementary and maybe appropriate for the pharmaceutical and food processing industries to harness this resource and generate specialized drugs or PUFA-enriched food products.

Vitamins are essential for fish. Requirement of vitamins in the diet varies depending on fish age, size, growth rate, physiological conditions, and diet composition. This study aims to investigate the effects of different levels of vitamin C (L-ascorbyl 2 – polyphosphate) on Siberian sturgeon fingerlings for 8 weeks at 6 treatments including the control (vitamin C free) (1), Treatments 2 and 6 respectively, containing 100, 200, 400, 800 and 1600 mg/kg vitamin C with 3 replicates for each. According to the results, the highest final weight gain was significantly obtained at treatment 5 (p<0.05), while the lowest final weight gain was observed at treatment 2. The results also showed that there was a significant difference between treatments in terms of daily growth and special growth rate (SGR) (p<0.05) and the highest figure of this factor was observed at treatment 5. However, there were no significant difference between treatments in terms of condition factor, body weight, protein yield, biomass, and final length (p>0.05), while the highest and the lowest figures of these factors were obtained at treatments 5 and 2, respectively. The lowest and highest figure of food conversion rate (FCR) were observed at treatments 5 and 2, respectively, although there was no significant difference between them (p>0.05). According to the results, it can be recommended that the best level of vitamin C which can develop growth and FCR is 800 mg/kg diet. This can be especially effective in the early weeks of growth.

In this study, acute toxicity of Paraquat was studied on
Mesopotamichthys sharpeyi fingerling. The acute toxicity test was performed in static renewal system based in the standard method proposed by OECD during 96 h, physicochemical parameters of water including pH, dissolved oxygen and Temperature were monitored. In order to determine the lethal range of paraquat a range finding test was carried out. The acute toxicity test was preformed in 5 treatments in triplicates. The obtained data were analyzed by using Probit analysis with 0.05 confidence limit. According to the results of this study, 24 h LC50, 48 h LC50, 72 h LC50 and 96 h LC50 of paraquat on Mesopotamichthys sharpeyi was 6.84, 5.29, 2.57 and 1.49 mg/l respectively. The Maximum acceptable toxicant concentration (MATC) of paraquat on Mesopotamichthys sharpeyi was 0.14 mg/l and the lowest was observed effect concentration witch is equal to 96 h LC50 was 1.05 mg/l. in addition paraquat lethal toxicity takes place in a narrow range of toxicant concentration.

The main goal was comparing some main sex and pituitary hormones of serum such as testosterone, 17β estradiol, GTH-I, GTH-II and stress indicators as cortisol and glucose in both male and female bloodstocks of Persian sturgeon (Acipenser Persicus) , which were catched from sea and assessing the relation of matural level with this sex hormones and the stress of migration and catching in this fish species. Sampling fourteen males and females serum has been done there from winter to spring 2013, in some Guilan sturgeon fishery stations. The results of gonadal examination showed that the broodstocks were in IV and V mature levels. After comparing serum steroids, there were much statistical significant differences in amount of testosterone in males (123.41±32.18 ng/ml) and females (44.87±18.92 ng/ml) (p˂0.05). But in the amounts of 17β estradiol, GTH-I and GTH-II, there were no statistical significant differences between males and females (p˃0.05). All of hormones were seen in males more than in females. After comparing stress factors as cortisol (587.42 ng/ml in males and 608.42 ng/ml in females) and glucose (138/85±31.02 mg/dl in males and 136/85±26 mg/dl in females) there were no statistical significant difference between males and females; but levels of this factors were much more than normal levels (p˃0.05).

This research was performed in June of 2012 in research center and technology fishery Dktr kyvan in Bndrchmkhalh the aim to determine the effect of different levele MOS prebiotic and Yeast cell wall on blood factors and immune of Oscar(Astronotus ocellatus) fingerlings for 8 weeks. after one week adaptating with cultural condition, 100 Oscar fingerling with weight average of 0/35 gr randomly to 4 aquarium for 8 week with attention to water temperature according to 10% of biomass fed.in this experiment with enrichment artemia nauplii with MOS prebiotic in tree experimental treatments 250,500.750 mg/l and one control group (each with 3 replicates ) 3 weeks Equivalent to 21 days the Oscar fish was feeding and the beginning of the fourth week to the end of the eighth week too with add Saccharomyces serevisiae prebiotie the tree treatments 1%,2% and 3% and one control group (each with 3 replicates ) the feed opening Oscar fingerling with name Biomar was designed. at the end of trial White Blood Cells (W.B.C ) and Red Blood Cells (R.B.C ), Hematocrit, Hemoglobin, Neutrophils and Monocytes between treatments and control group significant difference was observed and in all treatments there is a significant increase compared to control ,but Lymphocyte in control group was most of the all treatments .(P≤0.05). blood factors like MCH,MCV, MCHC and Investigated Eosinophils between treatments and control group significant difference was not observed. (P<0.05). in survey immune factors Serum lysozyme, IGM in all treatments was higher than the control group and had Statistically significant difference Compared to the control group. (P>0.05). Total Immunoglobulin between treatments significant difference was observed and in treatments 1,3% was higher of control group and treatment 2%.

In this study, the effects of starvation and feeding strategies on growth and carcass composition of Russian sturgeon ( Acipenser gueldenstaedtii ) juveniles with mean body weight (± SE) 77 ± 0.33 g were investigated for 8 weeks. The storage density was 20 fish in 1000- liter tank. For this purpose, a total of 180 Russian sturgeon were divided into 3 treatments included starvation, restricted feeding and full feeding with 3 replicates. Biometry was conducted to assess the growth performance every 2 weeks interval. Results showed that there was significant reduction in growth performances included weight gain, body weight increase, condition factor and specific growth rate of starvation treatment (P<0.05). There was observed significant difference in hepatosomatic index (HSI) and viscerosomatic index (VSI) between different treatments (P<0.05) as the least and the most rate of HSI and VSI was belonged to starved treatment and full feeding, respectively. The results of proximate carcass analysis showed significant difference in moisture between different treatments and fat between starved treatment in comparison with restricted feeding and full feeding (P<0.05). No significant difference in protein and ash contents was observed among the treatments (P>0.05). According to the obtained results, the starvation periods had negative effects on growth performance, carcass chemical composition, liver and visceral indices, so it can be concluded that Russian sturgeon does not compromise the long-term starvation periods and negative effects of starvation increasing with accession of starvation period but the negative effects of restricted feeding was less than starvation and improved feed conversion ratio. There was not observed any mortality using different diets.

Fish is an appropriate bioindicator to assess the contaminations originated from heavy metals in water resources. In this study, we aimed to measure the main Toxic metal concentrations (As, Cd, Cr, Ni and Pb) in muscle of Liza saliens which has an important role in human nutrition and health. The 6 samples were collected from Gomishan wetland by fishing nets during the spring and summer. In the laboratory, after samples digestion with concentrated nitric acid, all metals were analyzed by using both graphite furnace atomic absorption spectrophotometer and Inductively Coupled Plasma Mass Spectrometry. Mean concentration ans standard deviation of As, Cd, Cr, Pb and Ni were 12.243±2.459, 8.087±3.038, 12.935± 1.806, 15580± 735.39 and 4.529±0.08 (μg/kg dry weight) respectively. We used MVSP software to check out the relationship between metals and biometric characteristics by drawing dendrogram of the cluster analysis. The dendrogram analysis showed that a positive significant correlation exists among As, Cd and Cr concentrations with body length, age (r =+ 0.84) and weight (r =+ 0.6). But a significant negative correlation observed among Pb and Ni concentrations with samples body weight, length and age (r = -0.72). The levels of all metals were below than the established limits, except Pb which was exceeded than the permissible limits issued by international standards. HumanHealth Risk Estimates from fish consumption was done by calculating the hazard index (HI). The Hazard index values for all metals were below 1, except lead and cadmium (more than 1). Whereas HI > 1 suggests the probability of adverse health effects. Although the heavy metals analyzed in the wetland could pose immediate health risk to humans. Because of the fact that the Estimated Daily Intake values of Pb and Cd are more than Reference Dose values specified by EPA, with considering the absorption rate and bio-availability rate of 100% it is proven that a meal consumption of this kind of fish per week is risky for an adult consumers.

The aim of this study was estimate of diversity, density and frequency of crustacean zooplankton community of warm water fish ponds in Gonbade Kavous city at east of Golestan province. Sampling act was done during one culture period from June to November 2011. Finally 7 genuses were identify and recorded during study period. So that 4 genuses belongs to copepoda and 3 genuses belongs to cladocera. From statistical aspect, there is no significant differences between different 6 ponds observed (P>0.05). But there is significant differences between different months observed (P<0.05). So that, the highest density belongs to June and July months and lowest density belong to September and November months. The results show that the highest and lowest frequency percent of dominance genus belongs to Eucyclops sp, Cyclops sp, Daphnia sp, Diaphanosoma sp, Nauplius, Chydorus sp and Thermocyclops sp with 53, 16.5, 12, 11, 5.5, 1.5 and 0.5 % respectively. The correlation analysis between crustacean zooplankton community and water physico-chemical parameters show that total density of crustacean zooplankton community had significant correlation with NO3, PO4 and P-PO4 parameters -0.891, 0.939 and 0.968 respectively. Other water physico-chemical parameters had no correlation relative with crustacean community. The results show that crustacean of zooplankton community of fish ponds affected by ecosystem management, climate condition, water physico-chemical parameters and grower fishes.