عبدالمجید حاجی مرادلو

In fish farming industry, the use of nutritional supplements, including enzymes, is recognized as a vital strategy to enhance nutritional performance and growth. This study aimed to evaluate the effect of enzymatic extract from pyloric appendages on the growth performance and body composition of rainbow trout fry. Four dietary treatments were prepared, including a control diet (A: without enzyme) and three diets containing different levels of enzyme extract (B: 0.5 g/kg, C: 1 g/kg, and D: 2 g/kg of feed) with uniform protein and energy content. The results indicated that diets D and C exhibited the best growth performance compared to other experimental diets. These diets significantly outperformed others in terms of body weight increase and daily growth rate. Moreover, they showed the best feed conversion ratio, indicating efficient feed utilization. Additionally, diet D showed the highest specific growth rate and condition factor, while diet C exhibited the highest survival rate, although these differences were not statistically significant. The ash content in diet D was also significantly higher compared to other diets. Diets D and C significantly increased protein efficiency ratio and lipid efficiency ratio. The findings suggest that the inclusion of 2 g/kg enzymatic extract from pyloric appendages can improve the growth and nutritional performance of rainbow trout fry.

The skin is the first protective barrier against physical injuries and pathogens. Spirulina microalgae can be used to improve skin damage in fish due to its content of micronutrients, such as essential fatty acids, essential amino acids, and more. In this study, 360 rainbow trout weighing 50 grams each (with ethical code number 9821316001) were used at Gorgan University of Agricultural Sciences and Natural Resources. Before the final test, the effects of spirulina extract at concentrations ranging from 1% to 15% were evaluated on the fish. Subsequently, three doses—3%, 7%, and 10%—were selected for oral and poultice testing. After inducing skin injuries, the fish were treated both orally and with poultices for 28 days. On the 28th day, blood samples were collected, and biochemical and immune parameters were measured. The observed increases in glucose, cholesterol, triglycerides, total protein, globulin, and immunoglobulin plasma levels, along with elevated lysozyme activity after skin damage, indicate physiological responses aimed at recovery and the restoration of tissue integrity. The results of this study showed that administering spirulina supplements, particularly in the group that received a 7% concentration orally and used an ointment of the same concentration, had beneficial effects on various physiological parameters in injured fish.

Using herbal extracts as nutritional additives in aquaculture industry increases the resistance of fish to infectious agents while also providing a substitute for traditional antibiotics, enhancing the immune system, and promoting the growth of fish. The present experiments were designed to investigate the effects of a diet containing hydroalcoholic extract of savory (Satureja hortensis) on the growth performance, hematological parameters, and histopathology of the intestine in rainbow trout (Oncorhynchus mykiss) fry. For this purpose, 240 rainbow trout fry with an average weight of 2.02 ± 0.02 grs were randomly distributed into 4 experimental groups with three replicates and fed diets containing concentrations of 0 (control), 0.1%, 0.5%, and 1% hydroalcoholic extract of savory for 6 weeks. The results showed that growth performance indices including final weight, body weight gain, and specific growth rate significantly increased in the group fed with a diet containing 1% extract compared to the control group. Additionally, the number of white and red blood cells, and hematocrit levels increased in the groups fed with savory extract (P<0.05). The use of hydroalcoholic extract of savory in the diet of rainbow trout fry had no negative effect on the distal intestine tissue of the fish in all groups. Overall, the results indicated that feeding with 1% hydroalcoholic extract of savory in the diet could improve the health and better growth of rainbow trout fry.

So far, several studies have been conducted to increase aquatic production by affecting growth and reducing mortality through various feed additives, but studies on the effect of adding these additives directly to water are limited. The aim of the present study was to investigate the effect of adding Lactobacillus rhamnosus PTCC 1637 to water on hatching rate, yolk sac uptake and some growth indices during spawning to juvenile stages of rainbow trout. This study was divided into 3 parts; 1: day 1 to 7, 2: day 1 to 20 and 3: day 1 to 60, with the addition of concentrations of 106 and 107 CFU/mL into the water and also a control group. Results of the first and second parts showed that the range and duration of the hatching in all probiotic treatments were significantly different from the control and the yolk sac absorption were significantly shorter in both groups under 106 and 107 CFU/mL concentrations compare to the control (P<0.05).In the third part, the weight, length, feed conversion ratio, body weight gain percentage, specific growth rate and condition factor among probiotic treatments showed a significant difference with control (P <0.05). In all of these parameters, the best results were recorded in a treatment in which the hatched eggs were incubated from 1 to 60 days at 107 CFU/mL; The best feed conversion ratio was also recorded in the same treatment (P<0.05).Overall, increasing the duration of lactobacillus ramenosus treatment improved the performance of the hatching and growth factors in the early stages, as well as increasing the health status and growth in the later stages of fish life. Overall, the addition of bacteria to the water has improved the yield of growth and development in the early stages of life of rainbow trout and can be the easiest and most effective method.

Nutrition plays an important role in the functioning of the immune system and resistance to diseases. As a result, feeding and nutritional management are very sensitive and important. Nowadays, the use of substances that stimulate immunity and growth in the diet of aquatic animals is very important. The main reason for using these stimulants is their benefits, which include increasing growth, reducing food loss, increasing production, and obtaining a high-quality product. On the other hand, immune stimulants are added as supplements to the diet of aquatic animals and are used to prevent disease and improve the food conversion ratio. Seaweeds have high quantity of vitamins, minerals, protein, carotenoids, fiber, and essential fatty acids. In addition to being used as food, algae can have industrial, cosmetic, and medical uses. Algae have great economic importance due to having valuable polysaccharides such as agar, carrageenan, and alginate. Studies have shown that the use of dried algae as an immune stimulant in the aquaculture industry improves the physiological responses of fish to stress and disease, and as an immune stimulant in aquaculture, they increase growth, food efficiency, and biochemical quality of carcasses in various aquatic animals. The genus Gracilaria from the family Gracilariaceae is the largest genus from the Rhodophyta branch. They have a wide distribution worldwide and have been seen in polar, equatorial, and Mediterranean regions. However, there are limited studies regarding the use of Gracilaria gracilis algae powder in aquaculture. Considering the importance of common carp as one of the most important aquaculture species, the present study aims to investigate using different levels of G. gracilis algae powder in the diet and its effect on growth performance as well as some serum and skin mucus parameters in common carp.

This research was conducted for seven weeks in Shahid Nasser Fazli Barabadi Aquaculture Lab of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. In this experiment, common carp fry with an average weight of 19 g was used. The fish were adapted for two weeks and then kept in 12 fiberglass tanks (4 treatments 0, 0.25, 0.5 and 1% G. gracilis powder) with a density of 15 fish. The added ingredient in the diet was G. gracilis powder, supplied from South Iran. In this experiment, the basal diet was commercial extruded food size FFC from Faradaneh Company, Shahrekord, Iran and then the required amounts of G. gracilis algae (2.5, 5, and 10 g/kg) were mixed with the ingredients and made into the pellets. To investigate growth factors, the length and weight of all fish were measured. Fish mucus samples and blood samples were also collected. Data analysis and determination of significant levels were performed using SPSS 16 software and Duncan's statistical test with a confidence level of 95% and One-Way ANOVA test.

This research showed that the weight at the end of the period, the specific growth rate, and the food conversion ratio were not significantly different between the treatments containing red algae powder and the control group (p>0.05). Statistical analysis of the results showed no significant difference between the serum total immunoglobulin and total protein levels in the treatments fed with G. gracilis powder and the control group (p>0.05). The same results were noticed in case of skin mucus total immunoglobulin and total protein levels (p>0.05)

The results showed that adding G. gracilis powder (0.25, 0.5 and 1%) has no significant effect on growth and immune indices compared to the control group. The effect of adding herbal supplements to the diet on growth performance differs according to factors such as appropriate concentration, diet composition, and rearing management. Also, fish species, life stages, and experimental conditions are effective on growth performance results. The lack of significant difference between different levels of G. gracilis powder and the control group may be related to these reasons.

This study was conducted with the aim of investigating the effect of different levels of thyroxine hormone in rearing water and diet on growth factors in the early stages of growth of rainbow trout. The experiment was carried out in three stages: hatched eggs until complete hatching, hatched larvae until active feeding, and active feeding until weighing about 1 gram of fry fish. In each stage, the experiment was performed in three concentrations of thyroxine solution (0.03, 0.06 and 0.09 mg/liter) along with the control group (without thyroxine hormone) with 3 repetitions. Thyroxine was added to water in the first and second stages and to food in the third stage. At the end of the third stage, growth indicators were examined. The results showed that the highest final weight and length in treatment 9 were 1.53±0.04 and 5.85±0.31 cm respectively. The percentage of body weight gain and specific growth factors showed a significant difference compared to other treatments (p<0.05) and were 872.45±18.32 and 5.05±0.04, respectively. The highest food conversion rate and obesity rate in the control group were 0.78±0.004 and 1.14±0.07 respectively. According to the present study, thyroxine hormone has led to positive effects on growth factors in rainbow trout fry.

The present study was designed and conducted to investigate the effects of varying levels of choline chloride on the microbial flora of the rainbow trout, Oncorhynchus mykiss fry. A total of 750 fish were fed with diets containing 0 (control), 250 (Cho250), 500 (Cho500), 1000 (Cho1000), and 2000 (Cho2000) mg of choline chloride per kg of feed for 90 days. The required feed was obtained from the 21 Bayza Company. The amount of microbial flora and final weight was significantly higher in the Cho1000 and Cho2000 than in the control group. The addition of choline to the diet effectively improved the microbial flora. The most suitable amount of choline chloride was between 1000 and 2000 mg/kg in the diet of rainbow trout.

As an alternative to chemicals and antibiotics, probiotics have proven to be effective in promoting successful aquaculture. They can improve water quality and generate high-quality livestock. The current study aimed to investigate the effect of adding Lactobacillus rhamnosus PTCC 1637 to the rearing water on survival rate and water quality during spawning on juvenile stages of rainbow trout of Oncorhynchus mykiss. This study has been implemented in three groups (1: eyed eggs, 2: alevin, and 3: fry) and three treatments (1 × 106, 1 × 107 bacteria per mL of water, and a control group). The abovementioned bacterial concentrations in group 1 were added on the days 1, 3, and 5; in group 2, every other day; and in group 3, from the days 1 to 20 on every other day, and from 20 to 60 once every four days. The results showed that the direct addition of L. rhamnosus to the rearing water improved the water quality parameters (DO, pH, ammonia and ammonium; p<0.05). Also, according to the results of the second part, the highest survival rate (%) was observed in the eyed egg group (the days 1-20). The highest survival rate in the third part was found in the treatments receiving bacteria in the eyed egg (the days 1-60) and alevin (the days 8-60) groups. In general, the use of bacteria in the eyed eggs group (107 CFU/mL) that received bacteria from the first day exhibited a more favorable result. Finally, probiotics added directly into the rearing water is an effective method that causes increases survival and improves water quality parameters in O. mykiss.

Oxygen concentration is known as one of the limiting factors in aquaculture production. The present study aimed to evaluate the effects of vitamin E and zinc (Zn) on the metabolic rate and some growth indices in common carp Cyprinus carpio exposed to chronic low oxygen levels. So, 495 fingerling fish with an average weight of 15.38 ± 1.23 g were randomly selected and divided into two independent groups and fed with diets containing different amounts of vitamin E and Zn for 8 weeks. The vitamin E and Zn (E:Zn) concentrations were 0:0, 60:0, 0:20, 60:20 mg/kg for the control groups (C1-C4) and 0:0, 60:0, 0:20, 60:20, 0:40, 120:0 and 120:40 mg/kg for the treatment groups (T1-T4), respectively. All the physicochemical parameters of water except oxygen were the same for both control and treatment groups. Oxygen concentration for the control and the treatment groups were 8.7 ± 0.43 and 4.1 ± 0.38 mg/L, respectively. Chronic hypoxia led to a significant decrease in growth indices such as final weight and body length (p<0.05). In addition, the level of fish basic metabolic rate and maximum fish metabolic rate, aerobic metabolism scope in chronic hypoxia conditions were significantly lower than the control group (p<0.05). Nevertheless, using dietary supplements in the fish diet led to a significant improvement in the examined parameters in the treatment groups (p<0.05). The results of the present study showed that using food supplements, in addition to improving the metabolic rate of fish under chronic hypoxia condition, lead to an elevated efficiency of feeding and growth, which is directly related to the production efficiency of aquaculture systems.

Probiotics as alternatives to chemicals and antibiotics have proven to be effective in promoting successful aquaculture. They can improve water quality, increase tolerance to stress, generate high-quality livestock, etc. The present study aimed to investigate the effect of adding Lactobacillus rhamnosus PTCC 1637 to water on the intestinal tissue of rainbow trout, Oncorhynchus mykiss. This experiment was performed in three treatments including 1: days 1 to 7; 2: days 1 to 20; and 3: days 1 to 60, by adding the bacterium at 106-107 CFU/mL into the water and also a control group. The above mentioned concentrations of the bacterium in group 1 were added on days 1, 3, and 5; in group 2, at every two days; and in group 3, from 1 to 20 on every other day, then from 20 to 60, once in four days. At the end of the experiment, intestinal alteration was examined. The results showed that the highest length (247.2 µm) and width of intestinal villi (70.6 µm) were related to the hatched egg group from 1 to 60 days (hatched egg part), while the lowest in the control group. There was no significant difference between the average width and length of the intestinal villi in other treatments compared to the control group. In general, the use of bacteria in the eyed eggs group (days 1 to 60 at a concentration of 107 CFU/mL) showed a more favorable result than in the alevin and fry groups. Finally, the direct addition of probiotics to the water effectively improved intestinal morphology in O. mykiss.

The present study was conducted to evaluate some of the intrinsic immunodeficiency characteristics of serum and Cyprinus carpio in the face of salinity stress. In order to do so, 180 normal carp breeding fish with an average weight of 0.62 ± 50 g were prepared and transferred to Shahid Fazli Barabadi Aquaculture Hall of Gorgan University of Fisheries and Environment. After two weeks of adaptation, the experiment was performed in the form of 3 treatments including freshwater treatment (salinity ppt2 / 0.), Saline lip water treatment (salinity ppt 7) and saline treatment of the Caspian Sea and (salinity ppt 14). ) (Sea water was prepared from Gorgan Bay). In order to determine the intrinsic safety indicators (soluble protein, alkaline phosphatase and lysozyme) in response to salinity stress, sampling of serum and mucus of the skin in three separate time periods including the third, sixth and ninth day after exposure to Various salutes were performed. Total serum protein increased significantly at 7ppt and 14 ppt salts until the third day after salinity stress, and returned to normal on the sixth and ninth days before stress. The mucus solution protein in the 14 ppt treatment increased significantly on the ninth day after stress compared to the control treatment. Serum alkaline phosphatase levels showed a significant increase in 14 ppt treatment from the sixth day of exposure to stress until the ninth day compared to the third and sixth days (P <0.05). This increase was not significant compared to before the stress. On the ninth day, alkaline phosphatase mucus increased significantly at 14 ppt treatment (P <0.05). Serum lysozyme levels increased significantly at salinity levels of 7 and 14 ppt in the early days of exposure to salinity stress (P <0.05). At 7 ppt salinity, mucosal lysozyme levels increased significantly until the third day. From the sixth day to the ninth day, the process of change also increased significantly (P <0.05) and returned to normal before stress. In salinity 14 ppt until day 3, mucosal lysozyme levels decreased. This decrease continued until the sixth day, so that on the sixth day its rate decreased significantly compared to before the stress (P <0.05). After that, until the ninth day, the amount of mucosal lysozyme increased significantly (P <0.05). Also, the numerical values ​​of lysozyme activity in the skin mucus were several times higher (in some treatments up to 30 times) in the blood serum. In serum protein model, the range of protein bands from 70-22 kDa was observed. Mocus protein pattern was observed in the range of 70-9 kg. So that the density and number of bands was less than my head. Overall, salinity changes had a significant effect on serum and mucosal indices and changes in the protein pattern of the common carp carp (Cyprinus carpio). Based on the results of this study, it is recommended to use different levels of different levels of salinity stress and two-dimensional electrophoresis and detection of observed protein bands.

The fish's primary immune system in epidermis produces the mucosal layer as a surplus mechanism to cover the surface of the fish's body against infections. In addition to its physical functions such as reducing water friction and protecting against abrasion, it contains biologically active constituents, which is the first line of defense against pathogens. During the past years, the antimicrobial activity of various fish mucus has been studied. Due to the lack of information on sturgeon, in the present study, some properties of proteins in the epidermal mucus (Huso huso) as one of the native species of the southern coast of the Caspian Sea were evaluated. In this study, mucus was directly collected from fish surface in three different weight classes (0.4 , 4 and 40 kg) and some properties such as total protein concentration, chromatogram (RP-HPLC) and molecular mass profile of mucus proteins in three weight classes were compared. Antimicrobial activity of mucus was evaluated by disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The crude samples of different weights showed no significant difference in protein concentration (1.02 ± 0.03, 1.04 ± 0.01, 1.07 ± 0.02 µg/µl, respectively) but HPLC fraction No.4 in the third weight (40kg) showed a significant higher concentration in comparison to others (α=0.05). SDS-PAGE results revealed that the mucus samples contain peptides and proteins ranging from 5 kDa to 245 kDa with no considerable differences. All chromatograms showed similar numbers of fractions at similar retention time while the area percentage of fractions underwent significant differences in fractions 2, 4 and 9 (α=0.05). Disk diffusion showed the same antibacterial activity against A. hydrophila while group 1 (0.4 kg) had a significantly lower inhibition zone against S. iniae. All the samples possessed the same antimicrobial activity in MIC and MBC assays (MIC48=MBC48=25 µg). The current study revealed that all selected weight groups had the same properties in HPLC chromatogram and SDS-PAGE. Comparison of antimicrobial activity in MIC and MBC tests showed no significant difference between groups while in the disk diffusion test, there were significant differences in the antibacterial activity of weight groups exposed to S.iniaei, which could refer to the test competency. In conclusion, it can be claimed that in terms of protection (non-specific immunity), the first weight group (i.e. ≈ 0.4 kg) reached an evolutionary level as well as higher weights did (i.e. ≈ 4 and 40 kg).

Livergol drug is made from a herbal extract of Mary Magenta. Milk thistle contains flavonoids and has hepatoprotective effects. The purpose of this study was to evaluate the effects of livergol drug on growth indices and prevention of fatty liver disease in different levels of fat in Koi fish diets. For this experiment, 9 diets of different nutrients were prepared with 3 levels of 0, 0.5 and 1% of livergol and three levels of 5, 10 and 20% fat. The fish were fed for 150 days. After the end of breeding period, fish growth indices (end weight, weight gain, specific growth rate, survival rate and food conversion ratio) and samples of fish liver tissue were investigated. The results of the experiment showed that the final weight, body weight gain, specific growth rate and feed conversion ratio were significant in the experimental treatments (P≤0.05). While survival did not show significant difference among treatments (P≥0.05).The highest growth indices were observed in treatment 8 (fat 20% + livergol 1%). The results of the experiment showed that among all treatments, the highest liver toxicity among the all groups was observed in treatment 6 containing 20% fat and without livergol. The final result of the study showed that in all dietary fat treatments (5, 10 and 20%), adding livergol drug to the diet was probably due to the presence of silimarin reduced liver lesions in Koi fish.

The ovarian histological characterization of European Catfish on Anzaly lagoon was investigated. 154 female’s specimen in different size were caught by trap, ovarian were fixed in bouin׳s liquid. Samples were fixed, dehydrated, clarified, embedded and stained by H&E method. The tissues were supplied on 0.5µ size and analyzed by light microscope. The ovaries had six maturity stages which were as follow: Immature, Early Developing, Late Developing, Ripe Ovary, Running Ripe Ovary and Spent. Oocyte diameter was measured for 123 female’s specimen in the 2 to 5 maturity stages. In this study, the mean egg diameter, in stage II of gonad maturation was 1/4 mm and gradually increased in the later stages of development, in the fifth stage of the maturation process the average diameter reached to 2/36 mm and again in the sixth stage decreased the oocyte diameter. Also according the present study the type of gonad in this species under the climatic condition of Guilan Province was found on Group Synchronous and spawning in longer period.

The aim of this study was to investigate the effect of fish size and seasonality on the epidermis structure and protein profile of the skin mucus of Rainbow trout. Skin mucus samples were collected over three consecutive season periods including late winter, mid spring and early autumn. In each season, sampling was performed separately from three different weight groups including 2-20 gr fish (W1), 100-200 gr fish (W2) and 400-600 gr fish (W3). The results of histological analysis showed that goblet cell density and epidermal thickness increased with increasing temperature from winter to autumn in all weight groups. In juvenile (W1 fish), the size of goblet cells was not affected by the season, while in larger fishes (W2 and W3), the size decreased with increasing temperature in the autumn. There was a positive and significant relationship between fish size and density of goblet cells. Biochemical analysis of skin mucus showed that protein concentration increased simultaneously with an increase in goblet cell density. The protein profiles of rainbow trout mucus showed seasonal variations in all three weight groups. In autumn, the small proteins with molecular weights less than 35 kDa were more prominent, while these proteins were not observed in the winter. There were no significant differences in the mucus protein profile among different weight groups

The aim of this study was to investigate the effect of solid-state fermentation on quality properties, enzyme activity and apparent digestibility of nutrients of Kilka Anchovy. Kilka Anchovy meal were mixed with 25% wheat flour and inoculated with microorganisms (108 cell/ml) and kept in an incubator for 14 days at 37 ºC. Comparison of oxidation and hydrolysis indexes at Kilka Anchovy silage inoculated with microorganisms showed that S. cerevisiae was the lower free fatty acid (7.62 µ mole/g fish) and peroxide (12.47 meq peroxide/1000g oil). The lowest nitrogen non protein of Anchovy Kilka silagr was shown with fish silage inoculated with L. plantarum and B. subtilis. The lowest thiobarbituric acid (8.40 mg malonaldehyde/ kg) was showed at fish silage inoculated with fungi A. niger. The highest α-amylase and acidic protease activites was shown at fish silage inoculated with fungi A. niger and yeasts (S. cerevisiae and S. carlesbergensis), respectively. The in vitro digestibility of dry matter and crude protein with different levels of the fish silage increased. The highest of in vitro digestibility of dry matter and crude protein was related to S. cerevisiae (P>0.05). Generally, the results showed that S. cerevisiae had the best quality properties, enzyme activity and digestibility of nutrient of fermented silage compared with other fish silage inoculated with other micoorganisms.

Today, the increasing failure of chemotherapy and antibiotic resistance displayed by pathogenic bacteria infectious agents have caused the screening of new secondary metabolites with various chemical structures of marine crustaceans, molluscs and echinoderms with desirable antibacterial activity. This study was designed to determine the antimicrobial effect of muscle wall methanol and acetone extracts of four species of sea cucumber (Holothuria arenicola, H. leucospilota, Stichopus hermanni, S.horrens) in Chabahar coasts on some rainbow trout (Oncorhynchus mykiss) pathogenic bacteria (Lactococcus garvieae, Aeromonas hydrophila, Yersinia ruckeri and Streptococcus iniae).

An experimental study was conducted at in vitro conditions. Experimental variables include sea cucumber species, different concentrations of extracts and bacterial strains. After preparing extracts of mentioned sea cucumber by maceration method, the antimicrobial effect of outcome extracts from their muscle wall were investigated by two different methods disk diffusion and well diffusion.

At acetone extract of S.horrens, the highest growth inhibition zone for Y. ruckeri and A. hydrophila bacteria at 12 mg/mL concentration in disk diffusion method (11.10 and 13.03 mm) were seen respectively. Different concentrations of methanol extract of S. hermanni, H. leucospilota and H. arenicola were inactive on the tested bacteria. While, Minimum Inhibitory Concentration (MIC) of acetone extracts of S.horrens for Y. ruckeri and A. hydrophila was 0.625 and 1.25 mg/mL respectively and Minimum Bactericidal Concentration (MBC) for Y. ruckeri and A. hydrophila bacteria were 2.5 and 2.5 mg/mL respectively in well diffusion method.Generally, it type of extract, sea cucumber species and also bacterium strain are influenced on growth inhibition zone, MIC and MBC. Acetone extract of S. hermanni and S. horrens sea cucumbers can prevent the growth of Y.ruckeri bacterium tested by both methods (disk diffusion and well).

A parasite is a protozoan of the Holotrich ocular family. It is a mandatory parasite of freshwater fish and is a known cause of white spot disease in fish. The disease is highly contagious and can be transmitted from one fish to another without the need for direct interface hosts. Although one is often thought of as the pathogen of warm-water fish, its onset usually occurs when the water temperature is changing, especially in the spring when the water temperature is rising. The classic sign of infection is the presence of small white spots on the surface of the skin and fins of fish. These spots, which are actually adult parasites, penetrate the outer surface of the fishchr('39')s body and create a space in the surface layers of the body for feeding and movement to the surrounding areas, which can cause heavy losses if not treated in time. Therefore, it is very important to know it. The aim of this study was to evaluate, identify, prevent and treat this disease.

In the present study, the effects of different levels of beet molasses on some growth and survival indices, intestinal bacterial flora and length of villi in common carp were studied. In this experiment, 360 common carp species were used with a mean weight of 28 ± 2.5 gr The fish in 12 reservoirs were randomly distributed to 30 units per reservoir. After one week of adaptation, it was fed for a period of 8 weeks. The experiment was carried out in the form of 4 treatments and each treatment with 3 replications including: Molasses (treatment 1), diet containing 0.5% molasses (treatment 2), diet containing 1% molasses (treatment 3) and diet containing 2% molasses (treatment 4 ) And fish were fed daily with 3% body weight and twice daily with experimental diets. The food of the control group, the commercial food of the common carp of the company was enriched with no molasses. Growth and nutrition indices (body weight gain, body weight gain, specific growth rate, condition factor, nutritional conversion factor), total bacterial count of the intestine as well as the length of the intestinal paresis were performed at the end of the experiment. Data analysis at the end of the study showed that growth and nutrition indices (body weight gain, specific growth rate, condition factor, feed conversion ratio) were significantly different between treatments (p < 0.05). An examination of the total number of aerobic bacteria in the intestine showed that there was a significant difference between the treatments in the total number of aerobic bacteria (p < 0.05). Also, the study of peptic ulcer length in different treatments indicated that the length of the peptic ulcer was significantly different between treatments (p < 0.05).

The present study was conducted to evaluate some of the mucosal and serum indices of common carp (Cyprinus carpio) that exposed to salinity stress. In this regard one hundred and eighty fish (mean weight 50 ± 0.62 gr) were obtained from, after two weeks of adaptation randomly stocked in nine tank assigned to three treatments with three replicates including fresh water, Caspian Sea water (14ppt) and 50% sea water and 50% fresh water (7ppt). For measurement of immune factors after 3, 6 and 9 days of exposure, nine fish were taken from each treatment and anesthesia with clove powder. Serum and mucus were collected from different treatment and stored at -20 °C until use. The results showed different salinity had a significant effect on total protein, alkaline phosphatase and lysozyme of serum and mucosal (p < 0.05). But there wasn’t significant effect on protein content of mucus among treatments. According to the overall conclusion of the present study, results showed that mucusal lysozyme decreased with increase of water salinity in all measuring periods, but the amount of mucosal alkaline phosphatase in initial days decrease in 7 ppt salinity and in final days increase in 14 ppt salinity treatment, but serum alkaline phosphatase in first days of exposure to salinity decreased and then increase during experiment period. Total protein of mucus didn’t statistically affect during experiment. Serum total protein in initial days of exposure, increase and decrease during experiment. increased in the early and final days of sea water treatment. There was no significant difference among protein content of mucus in all treatment. The lysozyme and total protein parameters of the blood serum increase in the early days of exposure to salinity stress, but during the exposure total protein content of the serum reduced. The amount of alkaline phosphatase decrease in the early days of exposure to salinity stress, but increases with salt in time.

Controlled delivery technology of protein/peptide drugs from biodegradable particles has emerged as one of the eminent areas to overcome problems related to macromolecules formulation. The goal of the present study was to develop protein-loaded micro-particles using biodegradable polymer, polycaprolactone (PCL) and hydrogel from beluga cartilage. Bovine serum albumin (BSA) was used as a model for protein/ peptide molecules such as GnRH. The double emulsion (W/O/W) technique was selected as one of the most appropriate methods for preparing a drug delivery system for soluble proteins in water. The first emulsion was prepared using ultrasonic and the mechanical agitator was used for achieving the second emulsion. The hydrogel prepared by enzymatic digestion was used in the first aquatic solution. At the present investigation, three groups were considered as the drug delivery system: G1; (PCL/hydrogel/BSA), G2; (PCL/BSA) and G3; (PCL/Alginate/BSA). Findings showed that the morphology of particles was spherical and non-conglomerated in all groups. The comparison of average particle size among groups was also indicated that the particles.

Today in aquaculture to prevent negative effects of antibiotics The use of alternative, such as probiotics, prebiotics, organic acids, That can have positive effects on fish physiology activities. This study in order to done the synergistic effects of organic acid (potassium sorbate) and probiotic (Lactobacillus casei) in rainbow trout fry (Oncorhynchus mykiss). For this purpose of 360 pieces of rainbow trout with an initial weight (2.45±0.05), at 6 treatments with 3 replication include: Commercial diet (control), diet 107 CFU/g probiotic (Lactobacillus casei) (treatment 1), a diet containing 0.5% of potassium sorbate (treatment 2), a diet containing 1% potassium sorbate (treatment 3), The composition of the diet with %0/5 of potassium sorbate and 107 CFU/g probiotic (L. casei) (treatment 4) and the composition of the diet containing %1 potassium sorbate and 107 CFU/g probiotic (L. casei) (treatment 5) was carried out. Feeding in two stages and trial period of 60 days. Sampling of fish To search Digestive enzymes, intestinal Histomorphology and juveniles resistance against pathogenic bacteria (Yersinia ruckeri), was conducted At the end of the experiment. The results showed, The activity of digestive enzymes was significant in the different treatments (P<0.05). Also Survey intestinal Histomorphology showed no significant difference In different treatments (P>0.05). Results of the test resistance to pathogenic bacteria (Y. Ruckeri) showed That mortality rate during the 14 days was significant among treatments (P<0.05). In total, according to the results of this study, suggested Add, combine %0/5  potassium sorbate and 107 CFU / g probiotic (L. casei) in diets for rainbow trout.

Organic acids are natural crops and produced byo fermentation in plants and have a high potential for the replacement of antibiotics in the aquaculture industry. Hence, in this study, apple vinegar was used as a kind of organic acid in the diet of common carp fingerling. The aim of this study was to evaluate the effect of apple vinegar in different concentrations (0, 1, 2 and 4% of apple vinegar on basal diet) on some non-specific immune parameters of serum of common carp such as albumin (A), globulin (G), A/G ratio, total protein, lysozyme enzyme and alkaline phosphatase (ALP). Common carp fingerling with average weight of 15±0.5 g were fed with experimental diet for 60 days. At the end of the experiment, 10 fish pieces were randomly slaughtered in each replicate and anesthetized in clove solution and blood samples were taken. The amount of albumin and globulin measured in nutritional treatments did not show a significant increase compared to the control group (p>0.05). However, total protein increased significantly at 2% level compared with other treatments and control group (p < 0.05); also, in 2% apple vinegar, a significant increase in lysozyme activity was observed (p < 0.05). There was no significant difference in the level of alkaline phosphatase between nutritional treatments and control group (p>0.05).

In the present study, the effects of different levels of beet molasses on body composition and liver enzymes in common carp were studied. The experiment consisted of 360 pieces of common carp with an average weight of 28±2.5 gr. The fish in 12 reservoirs were randomly distributed to 30 units per reservoir. After one week of adaptation, it was fed for a period of 8 weeks. The experiment was carried out in the form of 4 treatments and each treatment with 3 replications including: Molasses (treatment 1), diet containing 0.5% molasses (treatment 2), diet containing 1% molasses (treatment 3) and diet containing 2% molasses (treatment 4) And fish were fed daily with 3% body weight and twice daily with experimental diets. The food of the control group, the commercial food of the common carp of the company was enriched with no molasses. The results showed that there was no significant difference in the amount of moisture and carcass ash in the control group compared with other treatments (P>0.05). The carcass fat content was significantly different in treatment with 1% molasses and 2% molasses (p < 0.05). The amount of carcass proteins in the treatment of 1% and 2% molasses had a significant difference with control (p < 0.05). The results showed that there was no significant difference in liver enzymes such as lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase between control and other treatments, but there was a significant difference in alkanin phosphatase levels in control treatment with other treatments (p < 0.05).

This study was conducted to evaluate the effects of lysozyme on dietary supplement scales in some growth factors, hematologic immunity indexes, and serum biochemical parameters in common carp (Cyprinus carpio). For this purpose, 180 pieces of fish were weighed 25.94 ± 0.1 g in 12 tanks and 4 treatments with 3 replications. After the adaptation period, fish were fed with diets containing 0, 0.5, 1 and 1.5 g / kg lysozyme for 8 weeks. At the end of the period, the fish were biometric and blood samples were taken and blood indices were examined. The results of this study showed that this immune stimulant had a positive effect on growth rate of about 26/37 grams and there was a significant difference between treatments (p<0.05). Lysozyme diet showed a significant difference between the number of white blood cells and the control group. There was an increasing trend in the number of hemoglobin in the experimental group. The differential count of white blood cells only showed a significant increase in lymphocyte count between treatments and control. There was a significant difference between treatments and control in neutrophil count. Also, in the study of biochemical parameters of blood, we found that there was a significant difference in all three factors and there was an increasing trend. According to the results of this study, it seems that the use of doses of 1 and 1.5 g / kg of lysozyme may have a beneficial effect on the improvement of blood and biochemical parameters of the serum and the growth of this breeding stock.