نشریه علوم آبزی پروری ایران
سال دوازدهم شماره 2 (پیاپی 22، پاییز و زمستان 1403)

In aquaculture, determining the production process of metabolites and changes in water quality and biodegradation according to the cultured species plays an important role in determining the capacity of the cultured systems and how to set the appropriate environmental conditions for the cultured species. Therefore, Therefore, in this study, in a completely randomized design, rainbow trout (Oncorhynccus mykiss) in four groups with an average weight of 20±3, 5±50, 9±100 and 10±200 g (SD±mean) were introduced to 300 liter fiberglass tanks (200 liters) as experimental treatments with three replications and fed commercial food for three days. Then the fishes were separated from the tanks and the biodegradation process of their metabolites was investigated. When the fish were present in the tanks and the ammonia was excreted from them, the concentration of ammonia in the water increased significantly until the third day of the experiment, but after the fish were collected, the ammonia excretion stopped. Following the nitrification phenomenon, the concentration of nitrite and then the nitrate increased and the nitrate accumulated in the water and its concentration increased over the time.  In the continuation of the experiment, due to the phenomenon of nitrification, the concentration of nitrite and nitrate increased. The phosphorus content of water (during the experiment) was significantly different among treatments (except the first and fourth weights) (P<0.05). An increase in electrical conductivity (between the starting and third days) was completely evident during the first three days of the experiment, but after the collection of fish, its increase continued with a lower intensity.  Significant difference was observed in total hardness value among different fish weights (P<0.05). Other elements such as sulfate, calcium, magnesium, potassium, sodium, iron, manganese, molybdate, and total hardness were also measured. However, some of them were produced in relatively small quantities by fish, or were insignificant in the diet. For this reason, their concentration in water was negligible, or their changes did not follow a specific law over time. The results of this study showed that, it is possible to measure the amount of nutrients produced in the consumed food unit and to maintain the water quality, the waste can be removed from the water as soon as possible so that it does not increase the concentration of pollutants in the water. According to the rates of food consumetion, temperature of the water and changes in water quality, it is possible to estimate the rate of biodegradation of organic matter and metabolite production in a culture system of rainbow trout.

Arabibarbus grypus (Heckel, 1843) is one of the native and valuable fishes of western and southwestern regions of Iran, especially Khuzestan province. The aim of this research is to measure feeding efficiency and gradual adaptation of Shirbout fish in different salinity. In this experiment, the survival rate, growth rate and feeding efficiency were measured in 4 levels of salinity (5, 15, 10, 20 g/L), with an average fish weight of 50.27±0.18 g for 2 weeks. In order to evaluate feeding behavior and tendency, Shirbout fish were fed and examined for 6 weeks with an average weight of 66.95±0.49 grams, at a daily rate of 5% of body weight with 4 treatments, including feeding with 60% pelleted alfalfa, pelleted common carp feed, Floating extruded common carp feed and floating extruded trout feed. In the study of feeding efficiency in different salinities, the fish continued to live up to 15 g/L salinity, but growth and feeding were not observed in any of the treatments. The results of feeding functions showed that the Shirbout fish prefers to feed from the bottom when choosing its type of food in captivity, but among the different diets examined, trout diet is more attractive for fishes (average eating time 11.82±0.10 min. In examining the effectiveness of the feeds, the results showed that the average daily growth rate in feeding with trout diet was 1.32±0.25 g per day and feed conversion ratio (FCR) was 1.53±0.29, which showed a significant difference compared to other treatments. Also, the chemical composition of the carcass had a higher protein content when fed with trout diet.

Today, heavy metals are one of the most important toxic pollutants in the ecosystem of aquatic systems, and aquatic animals are exposed to these pollutants. Bioaccumulation of heavy metals in aquatic animals is considered a serious risk in the human food chain. The aim of this research is to investigate the accumulation of cadmium, lead and tin metals in the sediments and in the soft tissue (muscle and hepatopancreas) of the blue swimming crab (Portunus segnis) in the Makoran sea (Tis, Bris and Pozm). 18 samples were collected in the winter of 2019 and transferred to the laboratory. After performing biometrics, preparing and digesting the samples, the concentration of heavy metals was read by an atomic absorption spectrometer. The research results showed that in all stations, tin metal concentration in hepatopancreas was more than in muscle and there was a statistically significant difference between the stations (P<0.05). The concentration of cadmium and lead metal between the stations was not significant. Lead metal was more in muscle than in hepatopancreas, although the difference was very low. However, cadmium, like tin, was obtained more in the hepatopancreas than in the muscle. The overall mean accumulation of heavy metals tin, lead and cadmium in muscle tissue was 9.33±4.5, 0.88±0.4 and 0.065±0.017 respectively; in hepatopancreas tissue 16.75±8.4, 0.37±0.13 and 0.08±0.009; in the sediment, it was 125±12.21, 8±0.32 and 0.14±0.0024 micrograms per gram of dry weight. According to the results, the accumulation pattern for heavy metals in all three studied areas, in tissue and sediment, was obtained as tin>lead>cadmium. In hepatopancreas tissue, which is a detoxifying tissue, a higher concentration of metals was accumulated than in muscle. Comparing the concentration of metals in the blue swimming crab muscle of the study area with international standards (WHO, FAO, FDA and NSHF) showed that the concentration of all three studied metals was lower than all the standards. Therefore, the consumption of the muscle of the blue swimmer crab in the study area does not have any risk. Comparing the results of this study with sediment quality standards showed that cadmium and lead metal had lower concentrations than sediment quality standards. Therefore, it can be concluded that the concentration of metals in the study area was not a threat to the organisms of that area.

The present study aimed to investigate the impacts of individual and combined usage of Lactobacillus rhamnosus (LR) and formic acid (FA) on the growth, digestive enzymes, immunity, and resistance to Aeromonas hydrophila bacteria in zebra fish (Danio rerio). A total of 240 zebra fish with an average weight of 68.2±2.4 mg was distributed into 12 tanks, with each tank containing 20 fish and fed with basic diet (T0), 1×108 CFU (T1), 0.3% FA (T2), and both LR and FA (T4) for a duration of eight weeks. The results indicated that the experimental diets had a significant effect on final weight, weight gain, specific growth rate, and survival rate. Fish fed with LR and FA bacteria (T1, T2, and T3) exhibited higher final weights compared to those in the control group (P<0.05). A notable difference in lipase and protease enzyme activity was observed among different experimental treatments; notably, T3 demonstrated the highest activity levels compared to other treatments (P<0.05). Additionally, there was a significant variance in lysozyme levels between different treatments; higher amounts were observed in treatments fed with LR and FA supplements (T1, T2 and T3), demonstrating significant differences from the control group. Following exposure to Aeromonas hydrophila bacteria for fourteen days post-treatment period termination revealed that zebra fish subjected to LR-FA supplemented diets had lower mortality rates compared to other groups. In conclusion as per this experiment's findings suggest that incorporating Lactobacillus rhamnosus along with formic acid supplements into zebra fish diet can potentially yield positive effects on its growth as well as overall health.

Considering the cultivation of Artemia as a valuable food source for feeding aquatic larvae and the importance of using healthy water resources, this study investigates the cultivation of Artemia urmiana in treated wastewater and salty ground water, examining their effects on growth, survival, and reproductive factors. Artemia was cultured under six treatments, each with three replicates, including two control groups (salinities 60 and 120 ppt), two salinized treated urban wastewaters (salinities 60 and 120 ppt) and two salty ground waters (salinities 60 and 120 ppt). During the culture period, all groups were equally fed with the single-cell algae Dunaliella salina and wheat bran suspension. Growth, survival, and reproduction factors were measured on days 8, 11, 14, 17, 20, and 23. The results showed that the growth rate of Artemia in the salinized treated Urban wastewater (salinity 120 ppt) was significantly higher than in other treatments (P<0.05). The survival rate was lower in the treated wastewater compared to the control group, but this difference was not statistically significant (P>0.05). The number of offspring and nauplii were significantly higher in Artemia grown in urban wastewater (salinity 120) than in the control group (P<0.05). From these results, it can be concluded that unconventional waters have the potential to create a suitable environment for the cultivation of A. urmiana.

The study of the effects of macroalgae extract and probiotics of the Bacillus species on the Pacific white shrimp for improving aquaculture practices, enhancing shrimp health and growth, effectively managing diseases, and promoting sustainability in the industry is vital. These findings could lead to significant advancements in shrimp farming and contribute to the overall success of aquaculture. This research examines the combined effect of a blend of brown macroalgae extracts (Padina astraulis, Sargassum ilicifolium, and Stoechospermum marginatum) and the single-cell probiotic (Bacillus subtilis IS0) on the growth performance and digestive enzyme activity of whiteleg shrimp, Litopenaus vannamei. A total of 2400 post-larvae with an average weight of 1.02±28.9 mg were randomly divided into eight groups of 100 shrimp each (with three replicates per group). The control group received a diet without macroalgae extract (MPE) or probiotic (P), while the other groups received diets containing different amounts of macroalgae extract (15 kg-1) and different concentrations of probiotic (1, 2 and 3 g 100 g-1 diet). Some groups also received combinations of the macroalgae extract and the probiotic at fixed concentrations. This feeding regimen lasted for 60 days. Spectrophotometer kits and devices were used to measure the activity of digestive enzymes.The results showed that the groups fed with P2+MPE and P3+MPE had the highest specific growth rates, final weights and weight gains, showing significant differences when compared with the control group and other experimental groups (P<0.05).In addition, these two groups also had the lowest feed conversion ratios. However, the survival rates of the experimental groups were not significantly different (P>0.05). The highest enzyme activities were found in the group receiving P2+MPE, with lipase at 8.33±11.0 U mg-1 protein, amylase at 543.33±15.27 U mg-1 protein and protease at 488.66±10.21 U mg-1 protein (P<0.05). Overall, the combined use of brown macroalgae extract at a concentration of 2 g 100 g-1 diet resulted in improved growth performance and increased digestive enzyme activity in white leg shrimp.

This study aimed to investigate the gut contents of the sea cucumber H. leucospilota in the recreational pier area of Kish Island, southern Iran. Sampling was conducted randomly at depths of 5 to 10 meters from the recreational pier station in both the summer and winter of 2019. Five samples were collected per season by divers. Sea cucumbers were stored at -20°C in aluminium foil. Additionally, environmental parameters such as water temperature, salinity, and pH were measured using a multimeter. Results showed that water temperature was significantly different (P<0.05) between summer (27.44°C) and winter (15.44°C). Salinity was higher in winter than in summer. After examining the gut content of the collected specimens, no empty intestines were observed in winter, while 45% of intestines were empty in summer. Feeding intensity was higher in winter (0.74±0.08) compared to summer. Analysis of gut contents revealed that diatoms, blue-green algae, foraminifera, gastropods, bivalves, nematodes, and amphipods were among the dominant organisms found in the digestive tracts of this sea cucumber species. In summer, diatoms comprised 44.8%, blue-green algae 31.4%, foraminifera 13.6%, gastropods 5.2%, bivalves 4.6%, nematodes 0.2%, and amphipods 0.2% of the gut contents. In winter, these percentages were 52.4%, 26.6%, 12%, 4.6%, 3.6%, 0.4%, and 0.4%, respectively. While significant differences were observed in the percentages of diatoms, blue-green algae, foraminifera, gastropods, and bivalves between the two seasons, no significant difference was found in the percentages of nematodes and amphipods. This study suggests that diatoms and blue-green algae are key components of the diet of H. leucospilota in the southern waters of Iran. Therefore, the use of these organisms for the cultivation of this sea cucumber species in this region is recommended.

Predicting Total Dissolved Solids (TDS) in water bodies such as rivers and lakes is challenging but essential for effective water resource management in agriculture, industry, and drinking water sectors. This study develops a hybrid intelligent model based on the Support Vector Regression (SVR) approach to predict the TDS levels in river water. Three optimization algorithms—Wavelet, Firefly, and Grey Wolf—were employed to model the TDS in river water. The study utilized hydrometric station data from the Kashkan River in Lorestan Province as a case study, using eight scenarios combining input parameters from 2003 to 2023. Model performance was evaluated using correlation coefficient, root mean square error (RMSE), mean absolute error (MAE), and Nash-Sutcliffe efficiency coefficient. Time series plots, box plots, and Taylor diagrams were used to analyze the model results. The findings indicated that the combined scenarios improved model performance. The evaluation criteria showed that the Wavelet-SVR model achieved a correlation coefficient of 0.980, RMSE of 0.881 mg/l, MAE of 0.473 mg/l, and a Nash-Sutcliffe efficiency of 0.990 during the validation phase. Overall, the results suggest that intelligent models based on the SVR approach can be an effective strategy for maintaining river quality for aquatic health.

This study investigated the role of microRNAs in regulating the expression of genes involved in the immune system of zebrafish through bioinformatics analysis. To achieve this, gene profiles related to the immune system of teleost fish were extracted from the NCBI website, and microRNAs targeting these genes were identified using the TargetScan and miRmap tools. The results revealed that genes such as tlr3, nlrx1, saa, cxcl12a, C3, mhc1ze, and mhc2dab play a crucial role in immune responses, inflammation, and oxidative stress. Notably, microRNAs dre-miR-30e-3p and dre-miR-723-5p, with scores exceeding 80, effectively regulated the tlr3 gene, which is essential for recognizing double-stranded RNA and activating innate immune responses. Additionally, dre-miR-155, dre-miR-2194, and dre-miR-2185-5p, were identified as key regulators of the nlrx1 gene, which is pivotal in immune pathways and oxidative stress. The expression of the saa gene, which is involved in inflammatory responses and immune regulation, is regulated by dre-miR-135c, dre-miR-135b, and dre-miR-135a. Similarly, the cxcl12a gene, which encodes the chemokine SDF-1 and plays a role in immune cell migration, is regulated by dre-miR-740, dre-miR-22b, and dre-miR-22a. Furthermore, complement system genes such as C3 are influenced by dre-miR-93 and dre-miR-128. The major histocompatibility complex genes mhc1ze and mhc2dab are strongly regulated by microRNAs such as dre-miR-101a, dre-miR-3906, and dre-miR-740. These findings, supported by comprehensive bioinformatics analyses, provide valuable insights into the role of microRNAs in regulating the zebrafish immune system and serve as a foundation for future experimental studies in this field.

The Caspian Sea trout is an economically important species of the Caspian Sea basin, and its population comes under strong pressure. Some reasons, including human activities, are accountable. In this research, the future presence distribution of this species as modulated by bioclimatic variables, and the response of this species to a set of bioclimatic variables in the present and future in different climatic situations were explored. Fishes were caught from different points of the Caspian Sea basin, and their occurrence was mapped. After recording the coordinates of their catch points, the samples were released. The probability of presence of the species in the future and present was explored throughout the basin using a MaxEnt model. Using the raster maps of species presence probability for present and future, response curves for these two time periods were constructed, and the overlapping area between the curves was calculated over a range of bioclimatic variables. The present research identified that the presence probability of the species in the future will suffer an immense decrease, and the species' response to bioclimatic variables will be diverse from the present. The area under the present and future response curves has been decreasing with time, showing an increasing difference in the response of this species with the passage of time.