نشریه بهره برداری و پرورش آبزیان
سال یازدهم شماره 1 (بهار 1401)

Appearance identification of Caspian salmon (Salmo caspius (Kessleri, 1877) and rainbow trout (Onchorhyncus mykiss (Walbaum 1792), which may have escaped from breeding cages on the southern shores of the Caspian Sea or breeding grounds and into the sea. In this study, 20 fish from different regions of the Caspian Sea: Bandar Anzali (3 salmon), Tonekabon (4 salmon, 1 rainbow trout), Nowshahr (1 salmon, 1 salmon) Rainbow mite), Fereydunkenar (3 salmon), Sari (1 salmon, 1 rainbow trout) and Miankaleh (3 salmon, 1 rainbow trout) were caught and used as much as possible using genomic sequencing He distinguished and identified these two species. Some tail fins were isolated from all samples and fixed in 96% alcohol for DNA extraction and Bioneer extraction column kit was used for DNA extraction. Preliminary results of mitochondrial genome sequencing showed the proximity of the sequenced genome to the species registered in GenBank. Specimens caught in Miankaleh, Sari, Fereydunkenar and Anzali with a very similar appearance to salmon showed high genomic similarity with rainbow trout in sequencing. The rest of the samples showed the same salmon sequence with the appearance of salmon. According to this study, there is a possibility of salmon escaping from breeding cages, which can have a great impact on the ecosystem of the region and aquatic animals, including other species of fish.

The encapsulation technique in lipid nanocarriers can be an effective way to resolve the limitations in the utilization of phycocyanin pigment extracted from spirulina due to special taste and odor, high sensitivity of these compounds, and undesirable color in products. Therefore, in the present study, phycocyanin was extracted from Spirulina platensis and its concentration was investigated. Nanoliposomes with chitosan coating (0 and 1% w/v) containing pigment were prepared and its physicochemical properties, morphology, and stability to different environmental conditions (relative humidity, temperature, and light) were evaluated. The mean size of nanoliposomes and polydispersity index ranged from 322.21 to 426.31 nm and from 0.27 to 0.28 in nanocarriers, respectively. The highest values of encapsulation efficiency of nanoliposome containing phycocyanin (81.4%) were obtained under optimal conditions in nanoliposomes with chitosan coating. Evaluation of the stability of liposomes against light, relative humidity, and different temperatures over storage showed an increase in the stability of phycocyanin encapsulated in lipid carriers and chitosan as a liposome coating increased the stability and controlled release of phycocyanin.

In the present study, the results of two-dimensional simulation of temperature and salinity have been investigated in the Gorgan Bay during one-year period of 2011-2012. In order to implement Mike 21 model, wind speed and direction, evaporation and precipitation, relative humidity, rivers inflow, air and water temperature, salinity, short and long wavelengths as well as temperature, salinity and water level fluctuations has been used in the open boundary of the model. The model was adjusted with optimization of wind drag, bed resistance and salinity dispersion, attenuation light intensity and latent heat coefficients, and verificated using salinity and temperature field data. The results of simulation showed that salinity and temperature values in the Bay have an increasing trend from east to west in all seasons. The maximum temperature difference between the eastern and western parts of the Gorgan Bay is 3.5 degrees Celsius. The maximum temperature difference between day and night in the Gorgan bay is 4 degrees Celsius. Temperature and salinity changes in the western part of the bay are significant due to the increase in local water change time. Salinity change in the southern shores of the bay is affected by river inflows and salinity in the estuarine area is 4 PSU. Due to the decrease in water level and the movement of bay water masses from west to east in winter, salinity values in the deep and central areas of the bay during this period compared to other parts with a maximum of 16.5 PSU has an increasing trend. The maximum salinity is 21.1 PSU in the western part of the bay.

Fish transportation in the aquaculture industry is one of the causes of stress and is inevitable. For this reason, providing methods to reduce transportation stress can improve fish health. The aim of this study was to investigate the effect of adding thymol to water on biochemical parameters of common carp during transportation. For this purpose, common carp were transported in plastic bags containing 0 (control), 5 and 10 mg/L thymol (three plastic bags per concentration) for 3 hours. Plastic bags were filled with 4 liters water and 8 liters pure oxygen. Blood samples were taken from all treatments immediately after transportation and 24 hours after recovery. The results showed that fish transportation and thymol concentration had no effect on the activity of alanine aminotransferase, alkaline phosphatase, total protein, globulin, albumin, and thyroxin in the fish blood plasma. On the other hand, after transportation, blood aspartate aminotransferase and lactate dehydrogenase activity increased and blood triiodothyronine levels decreased. Thymol, especially at a concentration of 5 mg/L, reduced the effect of transport on the activity of aspartate aminotransferase, lactate dehydrogenase and blood triiodothyronine. These results show that thymol reduces the stress and metabolism of carp during transportation. Therefore, a concentration of 5 mg/L thymol is recommended for short-term transportation of common carp.

In this study, the possibility of using locusts as a source of protein in the diet of rainbow trout and its effect on growth performance and blood biochemical parameters were investigated. 300 fish with average weight (5.08 ± 0.33g) with diets of 0% (control), 15% (SG15), 30% (SG30) and 60% (SG60) locust meal were formulated, with equal protein energy contents. Diet was distributed in a completely randomized design in three replications for eight weeks and twenty-five pieces of fish with the same conditions, in each tank. At the end of the experiment, growth, biochemical and safety indices were calculated based on standard formulas and the analysis was performed using Tukey test. The results showed that the highest final weight was observed in 30% treatment )89.34 ± 20.61%) and the difference between 0, 15 and 60% treatments was significant (p <0.05). In 60% treatment, a significant increase in feed conversion ratio was observed compared to the control treatment (p <0.05). In feeding fish with locust meal diet, glucose, cortisol, albumin, globin and IgM levels did not show significant differences between different experimental treatments (p <0.05). However, the amount of total protein, triglyceride and blood cholesterol showed a significant difference in experimental treatments compared to the control treatment (p <0.05). Therefore, it can be concluded that the use of 30% locust meal in the commercial diet of rainbow trout fingerling, in addition to adversely affecting blood and safety parameters, can improve growth performance.

In this Study, the egg white fish (Rutilus frisii kutum) hydrolyzed protein was produced. Hydrolysis was performed by alcalase enzyme in 60, 120, 180, and 240 minutes and their effects on degree of hydrolysation were evaluated. The results showed that the highest degree of hydrolysis was obtained in 240 minutes. Then, in order to separate peptides, based on their molecular weights, Millipore ultra filters (3, 10 and 30 KDa) were used. The antioxidant properties of hydrolyzed protein and peptide fractions 3, 10 and 30 KDa were measured, which can compete well with synthetic antioxidants such as BHT. Four antioxidant tests including DPPH, ABTS, Ferric reducing antioxidant power (FRAP) and Ferrous (Fe2+) ion chelating ability were evaluated at concentrations of 1, 2, 3, 4 and 5 mg, That with an increase in protein concentration, the antioxidant properties of hydrolyzed protein and peptide fractions were increased.

he aim of this study was to use a microbiome enriched with ammonia and nitrite oxidizing bacteria in the rainbow trout RAS system. A bacterial microbiome containing Nitrosomonas oligotropha and Nitrobacter winogradskyi (PAN) was added to a rainbow trout culture system (50 g) in the Aquatic Laboratory of the Fisheries Department of the University of Tehran and its effect on hematological parameters (hemoglobulin, hematocrit, erythrocytes, white blood cells, MCV, MCHC, lymphocytes, monocytes, and neutrophils) and stress (cortisol and glucose) as well as water quality of rainbow trout (Oncorhynchus mykiss) in a completely randomized design. In this experiment, a negative control (NC) group was also included for comparison with the experimental group. The results showed that by using PAN microbiome, the concentration of ammonia and nitrite produced was significantly reduced and as a result, this led to a reduction in stress and a reduction in immune suppression and improved growth. Therefore, the use of this bacterial group in improving the breeding system of rainbow trout is suggested by the rainbow trout breeding system.