نشریه بهره برداری و پرورش آبزیان
سال دهم شماره 4 (زمستان 1400)

The purpose of this study was to investigate the effect of sub-lethal concentrations of silver nitrate (AgNO3) on some biochemical indices and P450 gene expression of common carp. For this purpose, Common carp with a weighing average of 7 ±0.33 g were divided into 3 treatments (T1: 0.23, T2: 0.68 and T3: 1.13) and 1 control group, each containing 3 replicates, exposed to the effective concentrations of 0.23, 0/68 and 1/13 ppb for 14 day. At the end of the study, blood, gills and liver samples were collected for evaluate of some biochemical indices (total protein, Immunoglobulin, albumin) and P450 gene expression. The results showed that P450 gene expression in the gills of treatment 3 was significantly increased compared to the control group (P <0.05). The final results of this study in connection with exposure to silver nitrate toxin showed that with increasing duration and concentration of silver nitrate toxin has significant effects on biochemical indices of common carp and in most experiments reduces these indices. Total protein in the 2nd and 3rd groups significantly decreased compared to the control group (P <0.05). Total immunoglobulin levels increased with increasing concentrations of toxin, but this increase was not significant (P> 0.05). Albumin level in treatment 3 was significantly lower than control group (P <0.05) but in other treatments no significant difference was observed with the control group. Also, the expression of P450 gene under the influence of toxin in the liver and gills on day 14 showed the highest expression. Therefore, it can be concluded that silver nitrate can have destructive effects on common carp, which is one of the most important resource of the Caspian Sea.

Skin mucus with strong mechanisms can trap and collect pathogens before contact with the skin. The liver is a place of accumulation and purification of toxins and environmental pollutants and has different structural and functional complications in the face of pollutants. Fish mucus was collected from the epidermis of fish and the activity of alkaline phosphatase enzyme and the amount of soluble protein were measured. A part of liver tissue was prepared and prepared by classical histological method and stained by hematoxylin-eosin method. Then, the prepared slides were prepared using imaging system attached to a microscope and tissue type was examined and the type and severity of lesions were examined. Experimental treatments had no significant effect on the amount of mucus alkaline phosphatase (P> 0.05) but had a significant effect on the amount of mucus soluble protein (P <0.05). The amount of alkaline phosphatase and mucus soluble protein due to treatments fed nano-plastic toxin also increased with increasing concentration. Experimental treatments also had a significant effect on serum ALT and AST (P <0.05) but had no significant effect on serum ALP (P> 0.05), so that ALT and ALP due to treatments fed with The nanoplastic toxin also increased with increasing concentration and the amount of AST also decreased. Nanoplastic toxin caused complications such as necrosis, watery swelling, cloudy swelling, fattening, macrophage accumulation, lateralization of the nucleus, bleeding, and thinning of the sinusoid in the liver. So that swelling had caused the most complication.

This study was aimed to evaluate the effects of environmental factors (temperature and chlorophyll) on monthly and annual changes in catch per unit effort (CPUE) of caught Parastromateus niger using gillnet in the Gulf of Oman (Pozm, Ramin and Brise) in Sistan and Baluchestan province.The data of caught fishes were analyzed separately for determined centers (Pozm, Ramin and Brise) different months, from 2013 to 2018. Remote sensing data were used to evaluate the information of environmental factors (temperature and chlorophyll) during the study years. The amount of fishing in three fishing areas was recorded from 0 to 1346 tons during 2013 to 2018.The highest amount was related to April 2015 in the Pozm region. The maximum and minimum amount of catch per unit of effort during 2013 to 2018 is related to the Pozm region, which in 2015 was calculated as 0.73 kg roll net per day and in 2018, 0.01 kg roll net per day. Due to the non-normality of the data, the Kruskal-Wallis test was used to analyze the data and the Nemeny test was used to compare the means. The analysis results showed a significant difference between the CPUEs of the three regions, during different months and years (P <0.05). According to the results of the mean comparison, the amount of catch per unit of effort was not significantly different in Pozm and Ramin areas but they had significantly different with Brise port. The amount of catch per unit of effort in 1993 was significantly different from 1995 and 1996, while no significant difference was observed between other years. Effect of environmental factors on the catch of black Pomfret was investigated using the regression analysis method and no relationship was observed between them.

In this study, the effect of feeding with turmeric-enriched diets was investigated on hematological and ionic parameters after transport in common carp. For this, the fish were fed diets containing 0, 0.5, 1 and 2% turmeric for 2 weeks and then transported in plastic bags for 3 hours. The results showed that transport decreased the number of red blood cells and the percentage of lymphocytes, and increased the number of white blood cells, the percentage of neutrophils, MCV, MCH and MCHC in the blood and increased the concentration of calcium, chloride and potassium in the plasma. Also, transport had no significant effect on hematocrit percentage, hemoglobin concentration, and percentage of blood monocytes. Addition of turmeric to the diet reduced the negative effects of transport in the fish and the best results were obtained in the treatment of 1% turmeric. Based on this study, it is concluded that dietary turmeric supplementation improves hematological parameters and health of fish after transportation and the level of 1% turmeric is recommended for common carp.

In this study, the effects of different levels of galactooligasaccharide prebiotics on growth performance, survival, and some blood biochemical parameters of Binni fish, Mesopotamichthys sharpeyi was investigated. 240 fish with weight of 12.11 ± 0.1 g were fed in four treatments with three replications including: control group, T1 (1% prebiotic), T2 (2% prebiotic), T3 (3% prebiotic) for 56 days. The results showed that the final weight of fish in T2 was significantly increased compared to the control and the other treatments (P<0.05). The feed conversion ratio (FCR) in treatments with prebiotics was significantly improved compared to the control (P<0.05). The feed efficiency (FE) increased considerably in the treatments with prebiotics compared to the control group (P<0.05). The protein content of fish body in T1 and T2 treatments was significantly higher than the control (P<0.05). Also, the lipid content of fish body in T2 was significantly lower than the control group (P<0.05). The amounts of protein and albumin in fish plasma increased compared to the control group. But, the amounts of triglyceride, cholesterol, LDL showed significantly reduction in T2 treatment compared to the control group (P<0.05). While, the amount of HDL significantly increased (P<0.05). This study showed that the use of galactooligosaccharide up to 20 g per kg diet leads to the improvement of the assayed biological indices.

Providing healthy food and food security is one of the most fundamental concerns of countries. As for Iran, the policies made in this area are aimed at increasing aquaculture production and fisheries in the coming years. Increasing seafood consumption, in addition to promoting community health, can play an effective role in the socio-economic development of the country at the macro level by stimulating production. The purpose of this study is to present a model of seafood consumption simulation by examining the factors affecting seafood consumption. In order to investigate the factors affecting seafood demand, systems dynamics method has been used to develop the model. The model was simulated in Vensim DDS software. Using statistical data of 20 years period, the demand for aquatic food consumption was simulated and different scenarios of increasing demand have been forecasted until 2024. Proposed policies include marketing activities for processed seafood, raising awareness of aquatic food consumption health benefits, and increasing knowledge of aquatic food quality evaluation and cooking methods. The simulation result has verified the effectiveness of the proposed policies. With regard to the results of this study, in order to increase the demand for aquatic products by 1403, it is suggested to increase awareness about the health benefits of aquatic products, training in cooking and purchasing, and marketing of processed seafood.

The present study was carried out to determine and compare proximate composition and minerals (K, Na, Ca and P) in the edible tissue of Sillaginid species, including Sillago arabica, Sillago chondropus, Sillago indica and Sillago sihama in the southern waters of Iran. The fish species were collected from two stations in Persian Gulf (Bushehr and Hormuz Island) and one station in the Oman Sea (Chabahar) during a period from December to March 2020. Moisture, fats, ash and protein content were determined using AOAC standard method and the amount of minerals was measured using ICP-MS. The average moisture content was (70.3 ± 1.9 to 79.7 ± 1.3%), protein was (14.1 ± 2.1 to 21.9 ± 1.3%), fat was (1.5 ± 0.3to 3.9 ± 0.1%) and ash was (3.4 ± 0.8 to 4.5 ± 0.9%). The highest amount of elements was obtained for phosphorus (1060.4 ± 180.3-1693.2 ± 162.3) and then potassium (597.5 ± 82.3-1153.1 ± 137.6). This study showed that all four species of Sillaginid species in our country's waters are rich in protein with a protein content of more than 15%. All the fish analyzed for fat were lean with fat contents less than 0.5%. The Na/K ratio values, which was calculated less than 1 in all four species. The results of this study confirmed Sillaginid species as a valuable nutritional source with suitable protein and minerals content.