فصلنامه شیلات
سال هفتاد و ششم شماره 2 (تابستان 1402)

The present study was carried out with the aim of investigating the effect of a dietary spoiled fish meal along with the protective effects of vitamins E and C on the growth, hematological and biochemical indices of rainbow trout fingerlings. For this purpose, 240 rainbow trout fingerlings with an average weight of 12.75±0.25g were fed on 4 treatments diets including: 1: a diet containing fresh fish meal; treatment 2: a diet with spoiled fish meal; treatment 3: a diet with spoiled fish meal and low level of vitamin supplements (100mg/kg vitamin E, 200mg/kg vitamin C) and treatment 4: a diet containing spoiled fish meal and high levels of vitamin supplements (200mg/kg vitamin E, 400mg/kg vitamin C) for 60 days. At the end of the test period, the indices of final weight, specific growth rate, body weight gain, and food conversion ratio were calculated. Also, hematological parameters, cholesterol, triglyceride, HDL, and LDL were evaluated. Based on the obtained results, the final weight, specific growth rate, and body weight gain decreased in treatments 2, 3, and 4, while the food conversion ratio increased (P≥0.05). WBC and Hb increased in treatments 3 and 4 (P≥0.05). RBC and Htc% augmented in treatment 3 (P≥0.05). Triglyceride diminished in treatments 3 and 4 (P≥0.05), but cholesterol and LDL increased in treatments 2 and 3 and decreased in treatments 2 (P≥0.05). HDL has grown in treatments 3 and 4 (P≥0.05). It can be concluded that spoiled fish meal harms growth, hematological, and biochemical indices, and vitamin supplements are impacts on reducing these effects in hematological and biochemical indices.

Polysaccharides are one of the biomacromolecules that, in addition to their peculiar physicochemical properties, possess promising biological capabilities depend on chemical structure. The purpose of the present study was to evaluate the effect of membrane ultrafiltration on antioxidant properties of hydrolysed fucoidan from brown seaweed Nizamuddinia zanardinii. After removing pigments and low molecular weight compounds, the extracted crude fucoidan, was hydrolysed by 0.01N hydrochloric acid at 100°C for 20 minutes (FH20). Then, FH20 was fractionated using ultrafiltration with 2, 10, 30, 100 kDa membranes. The average molecular weight of fractions was 553.7, 39.2, 12.4 and 4.6×103 g/mol in KDa>100, 100-30 KDa, 30-10 KDa and 2-10 KDa, respectively. After separation based on molecular weight, the obtained fractions, compared to FH20, which were significantly capable of inhibiting DPPH free radicals (85.05-37.69%), ABTS radicals (89.65-55.43%) and reduction Fe3+ ions (absorption of 0.72-0.07). In the meantime, 2-10 KDa fraction had the greatest potential in inhibiting DPPH free radicals (85.05-74.12%), ABTS free radicals (89.65-75.16%) and reducing Fe3+ ions (absorption of 0.21-0.72). Overall, the results of this study showed that reducing the molecular weight of fucoidan to a specific range could lead to significant increase of antioxidant activity.

This study was conducted in order to investigate and compare the effect of cloves, propofol and electrical methods on the duration and recovery from anesthesia and their effects on some immune and physiological responses in beluga (Huso huso). The 270 beluga fish were randomly stored in 12 tanks. To induce anesthesia, a bath of 300 mg/L of clove powder, 5mg/L of propofol and an electroshock device were used as experimental treatments. In each treatment, immediately after the fish reached the stage of anesthesia, the duration of anesthesia and the recovery time were recorded separately and compared. The treatments were also evaluated for the anesthetic effects on the blood indices (red blood cell count, white blood cell count, hemoglobin concentration and hematocrit percentage), immune parameters (lysozyme and ACH50) and stress parameters (glucose and cortisol). In the examination of hematological indices, the highest level of hemoglobin was obtained in the electroshock treatment, which was significantly different from other treatments, and the lowest was related to clove powder treatment (P<0.05). The highest content of hematocrit was observed in the electroshock treatment and the lowest value was measured in the propofol and clove powder treatments (P<0.05). The results of immune parameters showed that the highest levels of lysozyme and ACH50 were in the electroshock treatment and the lowest values were in the clove powder treatment (P<0.05). Also, the results of stress indicators showed that the highest levels of glucose and cortisol were detected in the clove treatment and the lowest values were in the electroshock treatment. The results of this study revealed that the immune and stress indicators of the fish that underwent electrical anesthesia were better than the clove and propofol methods. Therefore, electrical anesthesia is a fast, cheap, eco-friendly method that can be a potential alternative to chemical anesthesia agents.

The possibility of hybridization of sturgeon has been reported in nature, but sometimes in public and private breeding centers and research centers, it is possible different sturgeon species hybridize together artificially due to the lack of sperm of the same species or more eggs. If the chromosome number of the two species is the same, the hybrid offspring are fertile and very similar to the parents, but because reproduction is usually done for conservation; The use of hybrid breeders to reach the pure population of that species is not appropriate and different diagnostic methods such as molecular methods should be used to distinguish pure hybrid species. In this research, seven suspected fin tissue of Acipenser nudiventris were sampled and stored in 96% alcohol and DNA was extracted in a molecular laboratory by ammonium acetate method. Sex determination was done by using female locus markers and a mitochondrial gene marker and two nuclear markers were applied for species and hybrid identification. Barcoding of suspected A. nudiventris with mitochondrial marker showed all seven fish have maternal genome of A. nudiventris and they are hybrid with Beluga according two nuclear markers. This research properly showed it is possible to distinguish sturgeon genome and hybrids with compilation of mitochondrial and nuclear molecular data.

This study was carried out with the aim of investigating the effect of diazinon insecticide chronic toxicity as one of the most widely used poisons used in agricultural lands and gardens around Lake Urmia on growth, survival, antioxidant and digestive enzyme activity indices of Artemia urmiana. First, the LC50 of diazinon insecticide for different age stages, including nauplii, post larvae and adults, were measured at 24, 48 and 96 hours using the probit analysis. The LC50 of diazinon for nauplii 23.769, 0.992, 0.008, post larvae 2.231, 0.015, 0.002 and adults 0.919, 0.038, 0.007 (mg/l) were obtained. To investigate the effect of chronic toxicity of diazinon, A. urmiana was cultured in the form of 4 treatments, control, 25% LC50, 50% LC50 and 100% LC50 for 15 days. The growth and survival indices were measured on days 8, 11 and 15, and the activity of antioxidant and digestive enzymes of the biomass were measured at the end of the period. The highest amount of growth and survival was observed in the control treatment and the lowest in the 100% LC50 treatment (P<0.05). The activity of superoxide dismutase decreased in 25% LC50 and 50% LC50 treatments (P<0.05). The activities of catalase and glutathione peroxidase enzymes also decreased in the 25% LC50 and 50% LC50 treatments compared to the 100% LC50 treatment (P>0.05). There was no significant difference between different treatments in the activity of alkaline protease and lipase enzymes (P<0.05). Alpha-amylase enzyme activity decreased with increasing diazinon concentration (P>0.05). In general, it can be concluded that diazinon reduces growth and survival in A. urmiana and has negative effects on enzyme activities. According to the results of the present research, in order to preserve this species, the use of diazinon insecticide in the areas around Lake Urmia should be controlled.

The effects of dietary aflatoxin B1 (AFB1) and zearalenone (ZEA) co-contamination on goldfish, Carassius auratus, was investigated. Total of 540 C. auratus fingerlings with an average body weight of 6.25±0.12g were randomly distributed in nine different experimental groups with 3 replicates comprised of three dietary levels of AFB1 (0, 50 and 100ppb) and ZEA (0, 500 and 1000ppb). Fish were fed with the experimental diets for 60 days. Then growth and nutritional indicate and pathology of gill and intestinal tissue were investigated. The results showed that dietary AFB1 and/or ZEA contamination depressed the growth performance, and nutritional indices of the experimental groups; the highest and lowest WG, final body weight, TGC and DGC were belonged to control group and AFB50ZEA1000, respectively (P<0.05). Although the nutritional indices, including PER, PPV and LER, were not significantly different among the experimental groups (P>0.05), the fish fed the diet containing 500 ppb ZEA had the lowest value of LPV (P<0.05). The highest intestine tissue inflammation (4.0±0.75) and necrosis (4.0±0.75) scores were observed in AFB100ZEA500 group (P>0.05). Also, the simultaneous presence of AFB1 and ZEA in the diet increased the severity of the gill tissue damage, including hyperplasia, congestion, hemorrhage, and lamellar fusion in almost all treatments containing AFB1 and ZEA (P<0.05). The results revealed that dietary co-contamination of AFB1 and ZEA could negatively affect fish performance at concentration even lower than those indicated in the literature implying that the safe feed mycotoxin thresholds would be revised in terms of fish welfare and performance.

Biofloc is a novel technology that can improve aquaculture production and also pursue sustainable aquaculture goals. In this experiment, the impact of the different C/N ratios on water quality, growth performance and immune response of Cyprinus carpio (initial weight; 11.75±0.53g) reared under biofloc conditions were investigated. Four levels of C/N ratios, using the addition of a carbon source (sugar), 10, 15 and 20 and the control without adding carbon (Control group with 40-50% daily water exchange) were consisted of the experimental treatments. After 8 weeks, fish were subjected to acute ammonia stress (0.5mg/L) for 6 hrs. Stress indicators such as glucose and cortisol were measured and statistically compared before and after exposure to ammonia. Total ammonia nitrogen (TAN) concentration was significantly higher in C10. The growth of fish was significantly higher in C15 while the feed conversion ratio had no statistically significant difference. Serum immunoglobulin, lysozyme, ACH50 activities were significantly higher in the C/N groups than in the control. Stress indicators (glucose and cortisol) showed no significant change before exposure, while after ammonia stress, their levels increased in all groups and the highest level was observed in the control group. Overall, biofloc (C/N manipulation) had an anti-stress effect, and the culture of common carp in the biofloc system with the lowest daily water exchange could be recommended.

Phycoerythrin (PE) is a naturally produced colorant with great fluorescent and antioxidant properties, which has an important potential in food pharmaceutical industries. This study was conducted by randomly experimental design in order to optimize the phycoerythrin extraction under different independent variable (biomass: buffer ratio, buffer ionic strength and cellular disruption method) from Caspian Sea red macroalgae (Osmundea caspica). Purity and concentrations of PE changed significantly under different treatments (P<0.05). The highest PE purity and concentrations was obtained in 100Mm sodium phosphate buffer and 1:20 biomass: buffer ratio. Therefore, the positive correlation has been observed between increasing levels of buffer ionic strength with PE purity and concentrations while lowest PE purity and highest PE concentrations (mg/gr fresh algae) were obtained with increasing level of biomass: buffer ratio. Antioxidant activity of extracted PE was evaluated by measuring the free radical scavenging ability using DPPH. PE was found to have better free radical scavenging activity at highest concentration with dose-dependent manner. Therefore, the obtained phycoerythrin in 100mM buffer in the extraction process approximatlly with a purity of one can be introduced with the aim of application in the food industry.

According to the official reports of the Ministry of Health, Treatment and Medical Education, the corona virus or covid-19 was seen in our country (Iran) from the last months of 2018 and quickly turned into an epidemic. The entry of this virus into the country not only involved the country's health system and caused illness and death of many compatriots, but also had a significant impact on the country's economy in the production and trade sectors. Global reports indicate the negative impact of Covid-19 on the fisheries industry, the same as activities of aquatic processing industries in different countries. In this article, the impact of Covid-19 on the country's aquatic processing industry investigated. In order to conduct this research, a questionnaire containing 31 questions on important topics such as the effect of Covid-19 on the volume and price of raw materials, sales volume, type of product, income, labor forces, changes in the marketing method of processed products and other factors were gathered and subjected to the processing. A total of 56 completed answer sheets were received from the processing centers. The results of the analysis of the response letters showed that during the Corona era, 60% of the respondents confirmed a decrease in the supply of raw materials for aquatic products, 72.2% with an increase in the price of raw materials, 67.9% with a decrease in the volume of production, 80% with an increase in the finished product price, 80.8% with decrease in the volume of domestic sales, 81.5% were faced a decrease in the number of customers. Also, 75% of farmers' responses have reported a decrease in the number of seasonal employees during the Corona era. In terms of product exports, 84% of the respondents said a decrease in the volume of exports.

Nowadays, the use of plants as one of the treatment methods of heavy metal pollution is considered. Cinnamon is one of the plants that has many therapeutic properties due to its effective ingredients. One of the most important effective ingredients of cinnamon is cinnamaldehyde. In the current study, the therapeutic effect of cinnamaldehyde on the lesions caused by zinc oxide (ZnO) in the gills of common carp (Cyprinus carpio) was investigated. In this study, common carp were divided into 5 groups in triplicates. Group 1 was considered as a control, group 2 was exposed to 3mg/L of zinc oxide, and groups 3, 4, and 5, in addition to receiving zinc oxide received concentrations of 3.6, 7.2, and 10.8mg of cinnamaldehyde in 100g diet, respectively for a period of 45 days. Then, 6 fishes were randomly selected from each group and their gills were sampled. The highest amount of zinc concentration, the lowest amount of total antioxidant activity and the highest amount of lipid peroxidation index were observed in group 2. Also, the most severe damage was observed in group 2 including epithelial cells hyperplasia, adhesion, atrophy and destruction of secondary lamellae, hyperemia, telangiectasia and infiltration of inflammatory cells. In the treatment groups with increase of cinnamaldehyde in the diets, zinc concentration, histopathology symptoms and lipid peroxidation index decreased, while the amount of total antioxidant activity increased. The results of this study showed that cinnamaldehyde has a protective and therapeutic effect against the damage caused by zinc oxide. The most protective effect was observed in group 5 including decrease of Zn bioaccumulation, improving histopathology symptoms, reducing the value of lipid peroxidation index and increasing the value of total antioxidant activity.

As one of the important economic sub-sectors of the country, the fisheries sector is under the influence of macroeconomic policies and decisions in terms of having special capabilities and capacities. The implementation of the government's trade liberalization policy has made the price of goods and services real, as well as increasing the country's foreign exchange earnings, and it has led to changes in the use patterns of production inputs and changes in production methods. The effect of such a policy is of great importance in the sustainability of the fisheries sector. In this study, the effect of commercial liberalization on the amount of catch in the southern fisheries industry investigated using regression methods in 1991-2019. The results of the fishing pattern showed that the variables of the number of boats and fishermen, the price and the catch of the previous period had a positive effect. While, contrary to expectations, the trade liberalization variable has not had a significant effect on the amount of catch so far. Of course, due to the use of modern equipment and the increase of fishing boats in the last few years followed by the significant growth of exports, it is expected that the amount of catch will also increase in the coming years due to trade liberalization. Therefore, by implementing sustainable management programs and increasing production through specialization and comparative advantage, it is possible to benefit from the benefits of trade so that the sustainability of resources maintained in the long term.

Temperature plays an important role in physiological processes in animals. In aquatic animals, the role of temperature in embryonic development has been proved and investigation and recognition of these changes in the production of larvae and quality of fish is of great importance in the economic production dimension. In this study, the effect of water temperature changes on hatching rate and survival of rainbow trout embryo, larvae and fingerlings were investigated. The experimental treatments included of waterborne temperature 10 (control treatment), 12 (treatment 1) and 14 (treatment 2) °C in three replicates. The mean percentage of hatching in treatments 1 (85.04±0.78) and treatment 2 (84.71±1.07) were significantly higher than control treatment. (82.90±0.97) (P<0.05). The mean percentage of larvae survival in experimental treatments showed a significant increase in treatments 1 (88.24±0.78) and 2 (91.10±1.57) compared to control (80.30±1.09) (P<0.05). Also, the lowest survival rate was observed in 14°C treatment, so it can be concluded that with increasing temperature, fish metabolic rate increases and at 12°C, the survival conditions of larva and fingerlings are better, in treatment 2, this rate was significantly higher than treatment 1 (P<0.05). In the later stages of growth, it was found that the survival rate of salmon fish decreased with increasing temperature compared to the control, so that the lowest survival rate was observed in 14 °C treatment.