هومن رجبی اسلامی

This 70-day experiment examined the effect of protease added to the commercial feed of Sterlet (Acipenser ruthenus) at concentrations of 0 (control group), 75 mg (T1 treatment), 150 mg (T2 treatment) and 300 mg (T3 treatment) per kg of diet on growth parameters and carcass composition. a number of 180 juvenile Sterlet with an average body weight of 6.02±0.34 g was randomly divided into 12 fibreglass tanks with stocking density  of 15 fish per each tank. At the end of the experiment, growth parameters indicated a significant difference between experimental treatments compared to the control group (p<0.05). The highest final weight (66.45 ± 0.33 g), weight gain (59.44 ± 0.52 g), specific growth rate (1.39 ± 0.02 %/day), protein efficiency ratio (2.43±0.11) and the lowest food conversion ratio (0.84±0.04) were measured in T3 treatment. However, the highest amount of condition factor (2.34±0.08%) was recorded in the T2 treatment (p<0.05). The carcass composition showed a significant increase between all the investigated indices in the experimental treatments compared to the control group (p<0.05). The highest amounts of dry matter (26.54±0.06%) and crude protein (15.27±0.02%) were measured in the T3 treatment. The highest amount of crude fat (8.07±0.05%) was in the T1 treatment. The highest amount of ash (2.27±0.02%) was observed in the T2 treatment. Based on the obtained results, it can be concluded that protease in concentrations of 75 to 300 mg per kg positively affected the growth and chemical composition of carcass A. ruthenus.

Bacteria release membrane vesicles into the extracellular environment but their activity is unknown. In this study, the use of extracellular vesicles isolated from the probiotic Bacillus licheniformis to protect rainbow trout fillets against spoilage and reduce of fillet quality was investigated. The probiotic B. licheniformis was isolated from edible fish. Probiotic vesicles were also made using the ultracentrifuge protocol. There was a significant difference in the size of probiotic-derived vesicles after 8, 24 and 48 hours of incubation. The results showed that after incubation until 16 hours, the number of cells increased to 8.09 10 108 CFU / ml. The pH reduced and reached to 4.002 at 24:00, which was the best incubation time for the bacterial growth. The vesicles derived from the probiotic B. licheniformis were collected and exposed to Shewanella putrefaciens at a concentration of 1011-107 vesicles per ml to confirm the antibacterial activity at 1011-10 vesicles per ml. Ml, with 44.34% had the highest inhibitory power of bacterial growth. Finally, rainbow trout stored at 4 ° C after covering with vesicles derived from probiotics and 0.5% sodium erythorbate were stored for 5 days, followed by red markers and Fillet quality indicators were examined. The results showed that the freshness and quality indicators of fish including peroxide, TVBN, total count of fillet bacteria and thiobarbituric acid in the group receiving probiotic-derived vesicles were lower than control group and the low-dose vesicle-derived group. Of probiotics. According to the results of this study, membrane vesicles isolated from the probiotic B. licheniformis have the potential for use in the food and storage industries while maintaining the appearance of fillets, and this new substance is a beneficial antibacterial agent for a long time and increase the longevity of fish fillets.

In this study, the effect of lack and phosphorus deficiency (dipotassium phosphate; K2HPO4) on the growth rate, biomass, biochemical content, and fatty acid profile of Desmodemus sp. was investigated for 14 days. Accordingly, Desmodesmus microalgae were grown in culture media containing no phosphorus (P0), 10 (P10), 20 (P20), 30 (P30), and 40 mg/liter (P40). The P40 treatment was considered as a control group that had the amount of phosphorus required in the standard culture medium BG11. Based on the results, the highest cell density, specific growth rate, and biomass production were simultaneously recorded in the P20, P30, and P40 treatments on the 14th day of culture, which showed a significant difference from the other two groups (P<0.05). In addition, the highest chlorophyll a was also recorded in these three groups, which showed a significant increase compared to the group without phosphorus (P<0.05). The lowest chlorophyll b was recorded in P0 (1.62 mg/L) compared to other experimental groups (P<0.05). The analysis of body composition showed the highest amount of lipid productivity (14.93 mg/liter per day) in P20 treatment, which has a significant difference with other experimental groups, except for P10 (13.17 mg/liter per day) (P<0.05). The highest protein productivity rate was measured in P30 and P40 groups (P<0.05) and the highest carbohydrate productivity rate (10.55 mg/L per day) was measured in P40 without significant difference with P30 (8.87 mg/l per day). The highest amount of saturated fatty acids was observed in P0 (47.66% of total fat) and the highest long-chain unsaturated fatty acids in P40 treatment (30.58% of total fat) without significant difference with P30 (29.33% of total fat). Based on the results, the concentration of 20 mg/liter of phosphorus is a suitable concentration for the cultivation of Desmodesmus sp. microalgae for the production of biofuel, while the concentration of 40 mg/liter of phosphorus is a suitable concentration for the cultivation of the microalgae for using in the food and aquafeed industries.

The present study was performed to investigate the effect of dietary nucleotides on the growth and apparent digestibility of Sterlet sturgeon, Acipenser ruthenus. Fish with an average body weight of 95.33±1.23g and total length of 0.30±0.5 cm were divided into 5 experimental groups with 3 replications, each containing 12 fish which were randomly distributed in tanks with 500 L working capacity. The fish were fed diets containing 0.0, 1.5, 2.5, 3.5, and 5.0 g kg-1 nucleotide. The experiment was conducted in a completely random design for 10 weeks. The results showed a significant increase in the weight gain percentage of fish in treatments of 2.5, 3.5, and 5.0 g kg-1 nucleotide than those in the control treatment (P<0.05), reaching the highest percentage of 119.07±19.97% in fish fed diet supplemented with 5.0 g kg-1 nucleotide (P<0.05). However, no significant difference was recorded in the values of this variable between fish-fed diets supplemented with more than 2.5 g kg-1 nucleotide (P>0.05). There was also a significant increase in the total length of fish fed diet supplemented with 5.0 g kg-1 nucleotide (25.5±0.8 %) compared to those fed the basal diet (17.76±0.73 %) (P<0.05), while no significant difference was found with those in fish fed diet supplemented with 3.5 g kg-1 nucleotide (P>0.05). The highest apparent digestibility of dry weight was 80.32±0.47% in fish fed a diet containing 5.0 g kg-1 nucleotide, while the lowest value was 73.24±0.45% in fish fed the basal diet (P<0.05). The highest apparent digestibility of protein was 90.94±0.24% in fish-fed a diet containing 5.0 g kg-1 nucleotide, which had a significant difference with that in fish fed a diet containing less than 2.5 g kg-1 nucleotide (P<0.05). However, no significant difference was observed in lipid apparent digestibility of fish between the experimental treatments (P>0.05). In general, findings of the present research indicated that dietary supplementation of nucleotide in the diet has a significant impact on the nutrient digestibility of sterlet sturgeon, with the best response obtained when fish fed a diet containing 3.5 g kg-1 nucleotide for ten weeks.

Numerous studies have investigated the positive effect of chitosan and nano-chitosan loaded clinoptilolite on growth performance, digestive enzyme activity, and intestinal histomorphology in different fish species. However, there are no data evaluating the potential effect of the composites on the fish stomach.

In the current study, the effects of chitosan and nano-chitosan loaded clinoptilolite on histological features and pepsin activity in the rainbow trout stomach were considered.

Chitosan and nano-chitosan loaded clinoptilolite were synthesized, and then two hundred and forty fish (~27.75 g) fish were distributed in eight groups each in three replicates. Ten days after adaptation, the fish were fed with eight diets, including control diet (CTR), clinpotilolite (T1), chitosan composites (T2, T3, T4), and nano-chitosan composites (T5, T6, T7) for 70 days. Afterward, all fish in each tank were anesthetized in clove extract (50 μl/l), and tissue samples were obtained for pepsin activity (n= 5) and histological assay (n = 5).

The groups administrated with nanochitosan composites showed the highest pepsin activity (P˂0.05). Additionally, histological examinations exhibited a higher epithelial height, increased mucosal density, and oxynticopeptic cells hypertrophy in fish fed composites compared to the CTR group (P˂0.05). Meanwhile, nanochitosan composite administration could cause higher reaction of secreted granules to periodic acid–Schiff (PAS) staining.

The findings demonstrated the potential application of chitosan and nano-chitosan loaded clinoptilolite composites for improvements in the histomorphology and pepsin activity of the rainbow trout stomach, resulting in higher growth performance.

The effect of zinc oxide nanoparticle as a mineral supplement in the diet on the white blood cells of rainbow trout was investigated in this research. Eight hundred specimens of rainbow trout fry (17.22±5.41 g) were randomly distributed in 18 experimental tank (six treatments each with three replications). The basal diet was prepared without zinc supplementation and used for the negative control treatment. Other experimental diets were prepared by adding 10, 30, 50 and 70 mg/kg of zinc nanoparticles and 70 mg of zinc sulfate (positive control) to each kg of the basic diet. Blood samples were taken from the fish at the end of the experiment to check the number of white blood cells and their differential count. After two weeks of adaptation, the fish were fed for 8 weeks with the diets corresponding to each experimental treatment. Blood samples were taken from the fish at the end of the experiment to check the number of white blood cells and their differential count. The results showed that nano zinc oxide has a significant effect on the leukocyte count with the highest number of 178,000±22,000 No. mm-3 in fish fed diet supplemented with 50 mg kg-1 Nano ZnO, which was significantly more than their number in fish fed with basic diet (p<0.05). Furthermore, fish fed diet supplemented with 50 mg kg-1 Nano ZnO diet had the highest lymphocytes percentage of 72.21±0.13%, while the lowest percentage of neutrophils was also found in fish fed diet supplemented with 50 mg kg-1 Nano ZnO. However, the actual number of neutrophils in the blood of fish in this treatment was 4.5 folds more than those in the negative control treatment. Findings of the present study showed that zinc oxide nanoparticles have a significant effect on the leukocyte properties of rainbow trout.

The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted anthocyanins were sensitive to the pH changes and lower 5 s the color change was observed. The color of films were pink, purple and green at acidic, neutral and alkaline, respectively. Furthermore, the films containing 0.5 and 1% anthocyanin extract were sensitive to the 0.8 and 1.4 M ammonia and after 20 min the color change were observed. The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted anthocyanins were sensitive to the pH changes and lower 5 s the color change was observed. The color of films were pink, purple and green at acidic, neutral and alkaline, respectively. Furthermore, the films containing 0.5 and 1% anthocyanin extract were sensitive to the 0.8 and 1.4 M ammonia and after 20 min the color change were observed. The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted anthocyanins were sensitive to the pH changes and lower 5 s the color change was observed. The color of films were pink, purple and green at acidic, neutral and alkaline, respectively. Furthermore, the films containing 0.5 and 1% anthocyanin extract were sensitive to the 0.8 and 1.4 M ammonia and after 20 min the color change were observed. The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted anthocyanins were sensitive to the pH changes and lower 5 s the color change was observed. The color of films were pink, purple and green at acidic, neutral and alkaline, respectively. Furthermore, the films containing 0.5 and 1% anthocyanin extract were sensitive to the 0.8 and 1.4 M ammonia and after 20 min the color change were observed. The effect of addition of Malva sylvestris extract on the structural (FT-IR, XRD, SEM), physical (moisture, water solubility, WVP), mechanical (TS and elongation at break) properties, color, sensitivity to pH and ammonia of starch/tragacanth films were investigated. Results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film. WVP of films were decreased with increasing the anthocyanins concentration. The TS of films were decreased with addition of anthocyanins and lowest TS were observed in the films containing 2% anthocyanins. The extracted

This study investigated the effects of different levels of vitamin E on growth performance and blood indices of Caspian trout (Salmo caspius) juveniles. Six diets with different levels of vitamin E including 0, 10, 20, 40, 80 and 160 mg kg-1 were prepared. The actual amounts of vitamin E in diets were determined using high performance liquid chromatography and were as follow: 4.9, 8.6, 17.4, 35.4, 78.8 and 137.0 mg kg-1. In total, 360 fish (initial mean weight of 9.32±0.34 g) were randomly distributed in 18 cylindrical tanks (20 fish per tank) with the working volume of 900 L. Each tank was randomly assigned to each of the experimental diets with 3 replications. The fish in each tank were fed with the respective diets for eight weeks and finally their growth indices and blood parameters were evaluated. The results showed that the final weight, daily growth coefficient and feed efficiency ratio of fish increased linearly (p<0.05) and quadratic (p<0.05) with increasing the vitamin E levels and reached the highest value in fish fed with 78.8 mg kg-1 vitamin E. Significant linear (p<0.05) and quadratic (p<0.05) increases in red blood cells (RBCs) and white blood cells (WBCs), hemoglobin content and hematocrit percentage were also determined by increasing in dietary vitamin E concentration. The percentage of neutrophils in fish blood reached the lowest level after feeding with the highest amount of vitamin E (137.0 mg kg-1 vitamin E) while the highest percentage of lymphocytes was recorded in fish fed with 78.8 mg kg-1 vitamin E. The findings of the present study showed that vitamin E could improve the performance and blood parameters of Caspian trout. The best level of vitamin E was estimated to be 82.16 mg kg-1 based on the daily growth coefficient and 102.98 mg kg-1 according to WBC number.

The use of dietary supplements in aquatic diets is one of the most important ways to reduce the stress of rearing operations. In this study, the effect of different levels of Lactobacillus brevis on stress-related indicators including antioxidant and liver enzymes, and hematological indices in rainbow trout were evaluated. In this study, 300 rainbow trout fry (9.5±0.3 g) with five experimental diets including control, LB1 (1× 106), LB2 (1×107), LB3 (1×108), and LB4 (1×109) were fed for 8 weeks. The results showed that the highest levels of superoxide dismutase and catalase were recorded in fish fed LB3 diet. Also, the lowest malondialdehyde value was recorded in the groups receiving LB2 and LB3 diets, which showed a significant difference compared to the control and LB1 groups (p< 0.05). Besides, diets supplemented with LB2, LB3, and LB4 significantly reduced the activity of aspartate aminotransferase and alanine aminotransferase enzymes compared to controls and LB1 (p< 0.05). Also, the level of alkaline phosphatase and lactate dehydrogenase enzymes decreased in all experimental treatments compared to the control group (p< 0.05). In this study, red blood cells count, the hemoglobin value and the hematocrit percentage in the groups receiving LB2, LB3, and LB4 diet significantly increased compared to the control group (p< 0.05) and the highest value ​​was recorded in the LB3 group. Based on the obtained results, the addition of L. brevis, especially in concentrations of 1×109 to the diet of rainbow trout has a beneficial effect on the antioxidant defense, liver enzymes, and hematological indices.

The aim of this study was to compare and evaluate the quality changes of rainbow trout fillets during live-storage in supply tanks. The studied fish included fish kept in a farm and the fish kept alive in supply tanks for 24 h and 72 h. The feeding was stopped 24 h before transportation and during live-storage in supply tanks. The examinations included chemical pH, total volatile nitrogen bases (TVB-N), Free Fatty acids (FFA), peroxide value (PV) and thiobarbituric acid (TBA) and bacterial Pseudomonas spp., psychrophilic bacterial counts, E.coli, Enterobacteriaceae, Total viable count (TVC), colorimetric tests (a*, L* and b*), tissue profile analysis (cohesiveness, gumminess, hardness, elasticity), and sensory evaluation (color, odor, taste, tenderness, appearance, overall acceptability). The pH value ranged from 6.68 to 7.18, which showed a significant increase with increasing the fish live-storage time in supply tanks (P<0.05). The highest levels of TBA, TVB-N, and FFA were measured in fish kept in live supply tanks at 72 h of storage. According to the standards for the amount of bacteria in fish fillets, in the 72h of the storage tanks, only the amount of Pseudomonas was within the permissible range, and in these tanks, other bacteria grew beyond the standard range. The red color of fish fillets or a * was decreased with increasing in the storage time. The fish fillet texture had higher elasticity, hardness and gumminess values with increasing in the live-storage time in supply tanks. Also, the cohesiveness of fillet tissue was increased with increasing in the live-storage time and it was increased from 0.41 N to 0.53 N (P<0.05). The sensory indices of the fish fillets had a significant decreasing trend with increasing in the live-storage time in supply tanks (P<0.05). According to the results, fish live-storage for more than 24 h in supply tanks caused the fillets to deviate from the quality standards in terms of bacterial, chemical and sensory parameters.

Providing comfort conditions for fish from the point of view of velocity uniformity and flow regime is one of the most important requirements of aquaculture improving the production conditions. In this research, for this purpose, by using computational fluid dynamics, Fluent software and k-ɛ turbulence model, the geometrical shape and pattern of water circulation in a fish breeding pond have been investigated. In this research, three square, circular and corner ponds have been selected as common ponds for breeding cold water fish and different scenarios have been analyzed after preparing the geometry of the ponds using flow uniformity and hydrodynamic indicators. The results of the simulation showed that the uniformity index in the circular pond was 0.940048, in the corner pond it was 0.919447 and in the square pond it was 0.874226. Therefore, it can be concluded that the uniformity index of the flow pattern and velocity field improves as the shape of the ponds approaches the circular state, although the physical space occupied by the ponds should also be considered.

The present study was designed to investigate the effect of density on some performance and activity of biochemical parameters of white-leg shrimp (Litopenaeus vannamei). Twenty-day-old larvae (PL30) were distributed at densities of 100, 200, 300 and 400 No. m-2 in twelve polyethylene tanks (working volume of 200 L) containing bioflocks and fed ad libitum using artificial feed. Each triplicate tank was assigned to one treatment. At the end of experiment, performance indicators, antioxidant enzymes activities and some of the stress parameters were determined. The results showed that an increase in the shrimp density under the biofloc system had a significant effect on the growth performance and hemolymph biochemical properties of white-leg shrimp and declined the final weight, daily growth rate and feeding efficiency ratio. However, the amount of biomass increased with increasing density and reached to more than 1.7 folds higher than that in under the density of 100 No. m-2. However, the antioxidant defense parameters including the activity level of superoxide dismutase, catalase and glutathione peroxidase enhanced with increasing the shrimp density in the biofloc system. Cortisol and glucose levels of the hemolymph also showed a decreasing trend with increasing density to 300 No. m-2,

Nonylphenol (NP) is an endocrine disrupting chemical widely used in industrial practices worldwide. It is estimated that large amounts of this estrogenic compound annually discharged into aquatic ecosystem. So this study was conducted to determine the effects of this pseudoestrogen compound on gonadal maturation and histopathology of ovarian and testicular tissues of rainbow trout, Oncorhynchus mykiss. To this end, a total of 360 rainbow trout (115 ± 5 g) were randomly assigned into 6 groups with triplicates and intraperitoneally injected with ascending doses of NP (10, 50,100 μg/g body weight) or a single dose of E2 (2 μg/g body weight) or solvent control (ethanol-coconut oil), whereas controls were not injected. The injections were performed at three times in 0, 7, and 14 days in complete dose form and tissue sampling was carried out on the 21st day. The male and female gonads were fixed in Bouin's fluid and 6 μm sections were prepared using the standard histological method. The sections were stained by the standard H&E staining method and the stained sections were examined using light microscope. The results demonstrated that oocytes development is affected by NP and E2 treatments, but had no effects on process of spermatogenesis. Moreover, various histopathological lesions were observed in ovary and testis tissues of fishes exposed to different nonylphenol concentrations, so that damages significantly increased with increasing concentration. Histopathological alterations in ovaries included atretic oocytes, hyperplasia of granulosa layer, nuclear pyknosis, cytoplasmic vacuolation, damage of yolk granules and nuclear disintegration. Hyperplasia of interlobular connective tissue, fibrosis of lobules, hypertrophy of sertoli cells, abnormal distribution and degenerative of spermatogonia, cellular vacuolation, and pyknotic nuclei were the most important tissue lesions observed in testicular tissue. In general, the results showed that NP has the potential to cause significant effects on gamete development stages and causes various lesions on ovarian and testicular tissues.

Selenium is an important trace element for maintaining the fish health. This study aimed to investigate the effect of sodium selenite on survival, growth and some hematological factors relating to the red blood cells of Siberian sturgeon. Three hundred Siberian sturgeon with initial mean weight 10.0±0.5g were randomly distributed in five treatments with three replications and fed with different levels of sodium selenite including zero (control), 0.2, 0.4, 0.8 and 1.6 mg sodium selenite for eight weeks. The results showed that the sodium selenite supplementation significantly increased the final weight and daily growth coefficient of fish with the maximum values of 25.63±0.68 g and 1.22±0.07% d-1 in fish fed with 1.6 mg kg-1 sodium selenite (P<0.05). The feed conversion ratio was significantly decreased after eight weeks feeding with sodium selenite with minimum of 1.79±0.10 in fish fed with 1.6 mg kg-1 sodium selenite (P<0.05). furthermore, equal to or more than 0.8 mg kg-1 supplementation of sodium selenite significantly enhanced the hemoglobin content, hematocrit percentage, and red blood cells count compared to the control (P<0.05). In conclusion, findings of the present study illustrated that 0.4mg kg-1 supplementation of sodium selenite is the best level for maximizing the growth of Siberian sturgeon, while 0.8mg kg-1 sodium selenite supplementation provides the best response in the synthesis of blood cells.

In this study, three protein hydrolysates were produced from muscle, fishmeal and fishmeal effluents (stickwater) of Anchovy Kilka fish (Clupeonella engrauliformis) using Alcalase (temperature=50ºC, pH=8.5, time=2 h) and their proximate compositions and amino acids profiles were analyzed. Based on the results, the highest protein content (81.97%) was in KMH and the lowest lipid (0.51%) and protein (70.31%) contents and the maximum ash (22.64%) were in SWH. The highest degree of hydrolysis was observed in SWH (17.23). KMH and FMH were rich in aspartic acid, glutamic acid and lysine while SWH was rich in glutamic acid, glycine and alanine. KMH had the highest content of hydrophobic and aromatic amino acids (p<0.05). SWH was the only treatment containing ornithine (1.44%). The results of amino acid profiles of hydrolysates and their calculated chemical scores showed that KMH and FMH were rich in the essential amino acids and met the nutritional needs to support optimal growth of human, common carp, rainbow trout, Nile tilapia and monodon shrimp. However, SWH could only meet the amino acid requirements of rainbow trout and the limiting amino acids for other species were methionine, threonine, arginine and isoleucine. Due to The high nutritional values and amino acid composition of KMH and FMH, they could be used as health promoting protein supplements. Also, the SWH composition showed that this effluent could be used for developing value-added products.

Caspian brown trout is one of the valuable, commercial, anadromous, and endemic species of the Caspian Sea, which has noteworthy the attention of many scientists. This study was carried out using Caspian brown trout fingerlings (n = 300) with an initial average weight of 42 g for two months. In this study, different amounts of carrot powder (total carotenoids) were added to fish diets including a control group and five treatments i.e. 0 (control), 50 (T1), 100 (T2), 150 (T3), 200 (T4) and 250 mg/kg (T5). The effects of different amounts of carotenoids were investigated on some blood parameters of fingerlings, including lysozyme, alkaline phosphatase, alanine aminotransferase, aminotransferase, glucose, total protein, and cortisol. According to the results, significant differences (p<0.05) were observed in the amounts of serum lysozyme between different treatments. Treatment 2 by an average of 51 ± 3.61 U/mL and control group by 40.67 ± 2.52 U/mL exhibited the highest and lowest levels of the enzyme, respectively. Based on the results, a significant difference (p<0.05) was observed between different levels of cortisol in the treatments, so that the highest and lowest cortisol levels in the control group and treatment 2 with 50 ± 7 and 26.67 ± 4.04 (ng/mL) was observed. In general, based on the results of this study, it was found that different levels of carotenoids in the diet of salmon brown trout can display a significant effect (p<0.05) on blood indices.

This study was conducted to evaluate the effect of dietary levels of lemon essential oil encapsulated in chitosan nanoparticles on hematological indices and antioxidant status of rainbow trout fry. Accordingly, the fish (4.74 ± 0.14 g in weight) were distributed in 12 fiberglass tanks with 20 fish per tank and were fed with different levels of lemon essential oil loaded in chitosan nanoparticles including control group with no additive (C0%), 0.5% (T0.5%), 0.75% (T0.75%) and 1% (T1%) for 8 weeks in triplicates. The results showed that the highest number of RBC was in T0.75% compared to T0.5% and C0% (p<0.05). The maximum hemoglobin value was observed in T1% and T0.75% compared to the other experimental groups (p<0.05). In addition, in terms of the blood indices, MCH index showed a significant increase in T1% and T0.75% compared to the other treatments. The maximum WBC and lymphocytes were observed in T1% compared to the other experimental groups (p<0.05). Serum antioxidant enzymes showed the highest catalase activity and glutathione peroxidase in T1% compared to the other groups (p<0.05). Furthermore, superoxide dismutase activity elevated significantly only in T1% compared to C0% (p<0.05). However, the oral administration of 0.75% and 1% of lemon peel essential encapsulated with nanochitosan resulted in a significant elevation in the serum malondialdehyde compared to T0.5% and C0% (p<0.05). Overall, the results of this study showed that the addition of lemon essential oil encapsulated in chitosan nanoparticles, especially at 1%, can enhance the hematological indices and antioxidant defense system of rainbow trout.

The use of dietary nucleotides in mammals and aquatic organisms has shown various positive effects on growth, immune system, gastrointestinal tract, and intestinal flora, improvement of reproduction, fat metabolism and increased resistance to diseases. The aim of this study was to determine the effect of dietary nucleotide (vanagen) on growth, survival and carcass composition in sterlet fish (Acipenser ruthenus). For this purpose, fish with an average weight of 95±1 g were divided into 5 treatments with 3 replications. The fish were then fed a diet containing 0, 0.15, 0.25, 0.35 and 0.5% nucleotide supplements for ten weeks. The results showed mean of final weight, weight gained (WG), specific growth rate (SGR), and protein efficiency ratio (PER) increased significantly with increasing nucleotide levels (P<0.05), and in the treatment containing 0.5% of nucleotides were the highest. (FCR) was the lowest in the treatment containing 0.5% (P<0.05). According to the results, the amount of protein and carcass fat in 0.25% was the highest and the lowest was observed in the control treatment (P<0.05). The results showed addition of dietary nucleotides to the diet of sterlet fish improved growth indices such as body weight gain, specific growth rate, and protein efficiency rate, feed intake and reduced feed conversion ratio. According to the results, concentrations between 0.25-0.5percent of vanagen nucleotides are recommended to achieve optimal growth and carcass composition in sterlet.

To investigate the effect of dietary folic acid (FA) on growth performance, serum biochemical indices and liver enzymes status of Siberian sturgeon (Acipenser baerii Brandt 1896), six isonitrogenou and isolipidic experimental diets were formulated to contain graded levels of FA including 0.60, 1.63, 2.71, 3.59, 4.82 and 5.68 mg/kg). Each diet was fed to fish (4.36±0.18g) in a flow through water system for 8 weeks. Examined indices in this study included relative growth rate, daily growth coefficient, feed conversion ratio as well as amount of cholesterol, triglyceride, alkaline phosphatase activity, glutathione S-transferase and malondialdehyde. The results showed that the use of folic acid at the level of 2.71mg/kg increased the growth performance and daily growth coefficient of Siberian sturgeon and caused a statistically significant increase in daily growth percentage of fishes (P<0.05). On the other hand, feed conversion ratio decreased with increasing dietary folic acid level from 0.60 to 2.71 mg/kg and then increased. No statistically significant difference was observed in the alkaline phosphatase activity of fish fed with different levels of folic acid (P>0.05). Glutathione S-transferase activity was not affected by different concentrations of dietary folic acid. Furthermore, different concentrations of dietary folic acid could not make a statistically significant effect on the level of triglyceride, cholesterol and malondialdehyde (P>0.05). The folic acid requirement of Siberian sturgeon based on the daily growth coefficient was estimated to be 1.65 mg/kg diet.

Global warming due to the excessive use of fossil fuels, environmental pollution, and rising greenhouse gases has led researchers to develop renewable energy sources such as the sun, wind, water, and biofuels. Microalgae, which are high in fatty acids, are suitable candidates for biofuel production.This study was designed to investigate the effect of different light intensities on the growth and accumulation of lipid in freshwater microalgae Chlamydomonas reinhardtii. For this purpose, microalgae were cultured at five light intensities of 50, 100, 200, 300, and 400 µmol m-2 s-1 for 20 days. The highest lipid content was (45.72±1.06%), and the lipid yield was (105.21±1.63 mg L−1 d−1), according to the growth curves in microalgae exposed to 300 µmol m-2 s-1. The amount of saturated fatty acids increased significantly with increasing light intensity, while monounsaturated and polyunsaturated fatty acids decreased. Among the fatty acids, methyl ester, palmitic acid, stearic acid, and alpha-linolenic acid showed the highest values at a light intensity of 300 µmol m-2 s-1. To evaluate the quality of biofuels, parameters such as saponification rate (SV), iodine value (IV), Cetane number (CN), degree of unsaturation (DU), long chain saturated factors (LCSF), and cold flow plugging properties (CFPP) was also estimated. The findings of this study showed that light intensity could improve the fat efficiency and biofuel properties obtained from the microalgae C. reinhardtii as a raw material in biofuel production.

In the present study investigated the antibacterial activity of the methanol and n-hexane extracts of the sea cucumber Holothuria leucospilota on Lactococcus garvieae and Aeromonas hydrophila. The antibacterial activity was determined using a serial dilution method with concentration 7.81, 15.62, 31.25, 62.5, 125, 250, and 500 mg/mL methanol and n-hexane extract of gonads and muscle tissue of sea cucumber. Then bacterial samples were added to dilutions, and optical density was recorded at 0 (before bacterial inoculation) after bacterial inoculation, 12 and 24 hours after inoculation. Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of the extracts were determined by the pour plate method. The results showed that the n-hexane hexane extract from gonads and muscle tissue of sea cucumber did not affect MIC and MBC of the mentioned bacteria. Meanwhile, methanol extract from gonads and muscle tissue of sea cucumber had antibacterial activity against Lactococcus garvieae and Aeromonas hydrophila.

The aim of this study was to evaluate the impact of human activities on health and determination of water quality using biological index of macroinvertebrates functional feeding groups. Sampling of macroinvertebrates was monthly performed using a surber sampler from 4 stations in 2017. During one year of sampling, 46475 samples of macroinvertebrates were collected belonging to 16 orders, 35 families and 49 genera. Macroinvertebrates included five functional feeding groups including Collector-Filterer (CF), Collector-Gatherer(CG), Scraper (SCR), Shredder (SHR), Predator (PRD) and Parasite. CG and CF groups had the highest relative frequencies in all study stations, except station 3, where CG and PRD groups were dominant, respectively. In stations with high pollution (especially station 1), the frequency of CG feeding group has increased significantly compared to other stations (especially stations 2 and 4) (ANOVA; F=0.011, p<0.05). Based on the results obtained from the distribution of macroinvertebrates and their food behavior, the impact of human activities including the entry of agricultural, urban, and rural wastewaters to the little Zab river is quite evident and the stations affected by different types of effluents (Station 1 and 4) had the most unfavorable conditions. Therefore, by examining the macroinvertebrates functional feeding group with the least time and cost, it is possible to find possible anomalies caused by human activities and changes in water quality of little Zab river ecosystems.

In the present study, the effects of dietary sodium propionate as an acidifier additive on some indices of growth, survival rate, and serum immunity of goldfish were investigated. In this study, 240 fish with an average initial weight of 7.2±0.75 g were randomly distributed in 12 aquariums. The fish were fed with the levels of 0 (control), 1.5% and 2.5% sodium propionate in the feed for 60 days. The results showed that weight gain, weight gain percentage, specific growth rate, condition coefficient, and survival rate in the treated fish were significantly higher than the control group (P<0.05). However, the highest feed conversion ratio was observed in the control group (P<0.05). Also, the highest levels of serum immunoglobulin M (9.64±0.11 mg/l) and lysozyme (15.61±1.03 μg/ml/min) were observed in 2.5% sodium propionate treatment compared to others (P<0.05). According to the results of this study, the use of 2.5% sodium propionate in goldfish diet acts as a growth stimulator and can enhance the growth performance along with the immune system.

The present study investigated the effect of nanoliposome-coated astaxanthin (NA) in the diet on growth indices of rainbow trout. A total of 375 fish with an average initial weight of 31.00±2.00 g were divided into five treatments including 0 (control), 25, 50, 75 and 100 mg kg-1 NA. Each treatment had three replications and each replication contained 25 pieces of fish that were randomly stored in 15 tanks with capacity of 200 liter and fed with food related to the same treatment for 60 days. The results showed that the highest percentage of weight gain (225.22±13.80) was related to the treatment of 75 mg kg-1 NA and the lowest (194.57±12.88) was related to the treatment of 100 mg kg-1 NA. Also, the highest daily growth rate (%) with 2.51±0.10 g d-1 was from the treatment of 75 mg kg-1 NA, which was significantly higher than the amount in the control (p <0.05). The highest rate of food efficiency was from the treatment of 75 mg kg-1 NA. The finding of the present study indicated that 83.61 mg NA has the best effect on the growth of rainbow trout and is recommended for culturing of this fish.

 The aim of this study was to investigate the effect of chitosan nanoparticles containing folic acid in the diet of rainbow trout, Oncorhynchus mykiss on growth and survival indices. For this purpose, rainbow trout with an average weight of 30 ± 2 g were divided into five experimental treatments: 0, 0.1, 0.25, 0.5 and 1 mg of chitosan/folic acid nanoparticles per kg of diet. Each treatment containing 25 fish in 3 repetitions in 15 tanks (500 liter) was designed into a closed-circuit breeding system. After making a manual diet and adapting the fish to the new conditions they were fed for 8 weeks. At the end of the experiment period, growth and survival indices were evaluated. The highest growth rate was recorded in the treatment of 1 mg/kg of chitosan/folic acid nanoparticles at the rate of 69.23 ± 4.34 g. With increasing Ch/FA nanoparticles levels in the formulated diets, the feed conversion ratio decreased linearly, which in fish fed with 1 mg/kg diet supplemented with chitosan / folic acid nanoparticles reached to 1.29 ± 0.08 (p < 0.05). On the other hand, the survival rate was the same in all treatments, but at the end of the period, losses were clearly observed in the control. The results showed that increasing the level of chitosan/folic acid nanoparticles in formulated diets will increase the growth rate and have a positive effect on growth index.