نشریه بهره برداری و پرورش آبزیان
سال هفتم شماره 4 (زمستان 1397)

Heavy metals are the most important environmental pollution, which are resistant in nature. Increasing levels of heavy metals in aquatic environments has biochemical and physiological negative effects on microalgae. Microalgae increase the antioxidant content in order to protect cells from stress conditions. Probably, heavy metals cause to creating oxidative stress by producing free radical stress. This various forms reacts with lipids and will cause of lipid peroxidation, membrane damage and inactivation of enzymes; so cell life will be compromise. In this study, effect of different concentrations of Lead (5, 10, 30, 50 and 100 micrograms per liter) on the antioxidant activity, Phenolic and flavonoid content of Spirulina Platensis microalgae methanol extract was studied in a period of 8 days. High performance of Phenolic compounds, especially Phenolic acids and Flavonoids in creating ant oxidative properties is important. Estimation of antioxidant activity according to DPPH method, indicated that the compounds levels of Phenolic and Flavonoid have been increased by the microalgae in order to coping with effects of heavy metals oxidative; and the highest antioxidant activity was seen at the last days of estimation. Also, assessing the special rate of growth showed that the highest rate is belong to the control group. In addition, by increasing the Lead concentration, the growth rate had more decreased.

Cell culture from fish brain have high potential in investigation of different responses to toxins, nutrients and growth factors. In the present study, to investigate the possibility of preparing long-term culture from Persian surgeon brain, characterization of neural stem cells and determining optimum temperature for the growth of cells, the front (olfactory lobe), middle (optic lobe) and rear (cerebellum) regions of Persian sturgeon brain were placed separately in the medium of DMEM/F12 with 15% FBS, penicillin-streptomycin and amphotrisin in incubator (250C, 5%Co2). The obtained cells were mostly fusiform. Cells from rear part of the brain are still alive after more than 8 months and 9 passages. To determination of optimum temperature for the growth of Persian sturgeon brain cells, cells were exposed to temperatures 20, 22, 25 and 280C and the number of cells in each temperature treatment was investigated for surveying growth condition. The highest growth and proliferation of cells were observed at 250C. To maintain cell stocks, the cultures were cryopreserved in liquid nitrogen. To characterization of neural stem cells, reactivity of cells from rear part of the brain with anti-nestin marker was investigated, that 11% of cells were immunopositive. According to the high stability of cultures from rear part of the brain, it can be used in different research areas such as virus characterization, ecotoxicology and gene expression.

Many reports have been recorded on the effect of medicinal plants as growth promoters in various aquatic species. This study was carried out according to considering development of intensive aquaculture systems and the necessity to use of medicinal plants as growth stimulator. This study was examined the effect of dietary orange (Citrus sinensis) peel powder on growth performance of common carp. To this purpose, 240 fish with average weight of 13.50±.20 gr were divided into 4 groups and 3 repetitions, fish were fed for 56 day (twice a day at 3% of biomass) with experimental diets (3 supplemented diets with 0, 1, 3 and 5 gr/kg orange peel powder and control group). Fish were fed twice a day at 3% of biomass. Result of this study showed that with increase of orange peel powder to 5 gr/kg all growth parameters were improved, but these were not significant for bwi%, specific growth rate(sgr), day growth rate(dgr), body weight gane%, food conversation rate(fcr) ) than those of control group. This may be due to the inadequacy of proper doses or a moderate feeding period. Based on the results of the present study, no significant difference was observed in all growth indices with orange peel diets compared to the control group.

Wetlands are aquatic ecosystems that keep the evolution tree from single cell to excellent animal and hence the most important gene bank are about vegetation and animal in the world after the rain forests. Shadegan wetland is the largest wetland in Iran, located south of Khuzestan province. In addition to its diverse capacities, this wetland is also important for the fisheries and environment. Nowadays, the name of the Shadegan wetland has been damaged in the list of wetlands that have been damaged. It is worth noting that in the field of environmental issues, the ideal management is in the balance of the environment. In such critical conditions, it is important to save the ecosystem and its components, so dewatering the wetland is very important. Therefore, the restoration of dry wetland in Khuzestan Province and their dehydration by sugarcane drainage are very much considered. Considering the importance of this issue, this study attempts to emphasize on the positive and influential aspects of sugarcane drainage entry in Shadegan wetland with the approach of improving aquaculture status in the area and in controlling dust.

This study was conducted to determine of different concentrations of clove oil (Eugenia caryophyllataon) on anesthesia, lethal stage and effect on hematological parameters on Barbus barbulus. For this purpose 78 pieces of fish with average weight: 100±3 gr, were arranged in 5 treatments: the treatment 1(control group) was not exposed to any type of anesthesia material. Four treatments were exposed to clove oil with different concentrations of (50, 100,150, 200 mg/l) of anaesthesia, and (1000, 2000, 3000 mg.L-1) doses used for lethal stage, each treatment was divided in to tree replicates. The pH, temperature of water and dissolved oxygen were 7/5-8, 20±2/65 ºC and 10±1/2 ppm, respectively. The 200 mg.L-1 of clove oil was determined as the best concentration for anesthesia and recovery. The lethal dose was 13 times of the effective dose of anesthesia and was 2600 mg.L-1. Blood samples were obtained at 0, 6, 12, 24h after anaesthesia, hematological parameters (number of red blood cells, hematocrit, hemoglobin, mean corpuscular hematoglobin (MCH), mean corpuscular volume (MCV), mean corpuscular hemogolobin concentration (MCHC), number of white blood cells, lymphocytes, neutrophils, eosinophils and monocytes) were measured. Hematocrit showed significant difference between lethal treatment and control group (P<0/5) but hemoglobin, MCHC, MCV, number of red blood cells, number of white blood cells, lymphocytes, eosinophils and monocytes did not show any significant difference between treatments (p>0.05), and the increasing trend of MCV was observed between treatments from control treatment to lethal treatment, respectively. Regarding the MCHC, there was a significant increase in lethal treatment with other treatments (except for 24 hours treatment) (p <0.05). Finally, given that the anesthetic substance of the clove oil has no lasting negative effects on hematological parameters on B. barbulus, and this effect has almost returned to its original state after 24 hours and due to the safety of this anesthetic for fish, as well as its negative effects on the environment, this anesthetic agent recommended for fisheries purposes.

This experiment was designed with the aim of effecting the use of live Eisenia fetida as a food supplement on the water quality of rainbow trout rearing tanks. Fish with a weight average of 58 g were placed in a completely randomized design in 4 treatments and each in 3 replicates. The fishes fed with different levels of 0, 25, 50 and 75% (control, T1, T2 and T3) of diets from live worms (including 50% moisture content) for 8 weeks at 18 °C. Comparing means obtained from water quality factors showed a significant difference in pH of control and other treatments and also do and tss among all treatment (P<0.05). The amovnt of TAN in the first sampling was significantly different from the above treatments, but this amount in the last sampling in dedicated a dearease in TAN and No significant difference was between treatment 2 and 3. The compersion of NO2 - and NO3 - inconsecuative sampling was found a significant decrease amony all treatment with increasing the amount of worm in the food (P<0.05). The use of worm at the level of 50% had the best growth and water quality of tanck reserver.

This study aims to investigate the concentration of strontium, potassium, sodium and sodium elements along the chronological transects of sectioned sagittae otolith as well as to compare the otolith morphometric parameters of Black pomfret (Parastromateus niger) from May 2016 to June 2017 at North coast of Oman Sea (Sistan and Baluchistan province). Morphometric characteristics including total length, total weight of fish, and otolith morphometric parameters including otolith length and otolith weight were investigated. The age determination was based on the existence of annual growth rings (opaque and transparent layers) on the otolithic sections. The maximum age was 6 years old and belonged to Black pomfret with a mean weight and length of 1957 ± 28 g and 483.3 ± 2.3 mm, respectively. There was a significant relationship between total length and age of fish and total weight and age of fish (p <0.05). Furthermore, a significant relationship was observed between otolith length and weight, fish length and ottolith length, and otolith length and fish weight. The strontium concentration generally increased by the increase distance from the otolith core (age). Sodium and potassium showed differences between the dark and bright regions of otolith between the ages of 4 and 6 years. But calcium and strontium did not show a seasonal difference. Also, the results of this study showed two parameters of otolith length and otolith weight as determinants of the species using otolith can be used. Also, the results of this study showed two parameters of otolith length and weight using as a species characteristic index.