جستجوی مقالات مرتبط با کلیدواژه « rainbow trout » در نشریات گروه « شیلات »

The aim of this study was to investigate the effect of adding cottonseed meal and a mixture of organic acids to the diet on growth parameters, economic justification, and nitrogen and phosphorus retentions in rainbow trout. For this purpose, six triplicate treatments consisting of six diets were considered in a 3 × 2 factorial design, where two levels of cottonseed meal (0% and 15%) and three levels of organic acid mixture (a mixture of lactic acid, citric acid, and potassium sorbate in equal proportions) at 0%, 0.5%, and 1% were added to the diets. A total of 270 rainbow trout with an average weight of 14.0 ± 0.35 g were stocked in 18 aquaria containing 40 L of water, with a density of 15 fish per aquarium. The above diets were offered to the fish for 8 weeks at a daily rate of 3 to 4 % of biomass. The aquariums were equipped with a semi-closed system including aeration, physical filter, biological filter, and UV filter, with a daily water exchange of 30% during the experimental period. After the feeding trial, sampling of the fish muscle was conducted. The results of this study showed that adding cottonseed meal to the diet had no significant effect on final weight, fish production per unit volume of water, or feed cost; however, it significantly reduced the growth rate and increased feed conversion ratio. Additionally, adding organic acids to the diet had no significant effect on fish growth parameters. The addition of cottonseed meal to the diet did not significantly affect the phosphorus and nitrogen content in the fish muscle; however, adding organic acids to the diet significantly increased the phosphorus content in the fish muscle. Overall, the results indicated that cottonseed meal could be used at a level of 15% in rainbow trout diet. Although this amount of cottonseed meal significantly reduces growth and increases feed conversion ratio, it does not have a significant economic impact on trout production. Furthermore, adding organic acids at levels of 0.5% to 1% to the trout diet, while having no positive effect on growth, efficiency, or feed cost, does increase the phosphorus content in the fish muscle.

This research aimed to investigate the effect of gamma-aminobutyric acid supplementation on the growth and survival indicators of rainbow trout fry kept at high density, for this purpose, 585 fry with an average weight of 5 ± 0.03 grams in 5 experimental treatments with High density (129 pieces in 69 liters) and a negative control group with normal density (69 pieces in 69 liters) were included. The test treatments included a positive control group, treatments 100, 200, and 300, which were fed with gamma-aminobutyric acid supplement sprayed to the commercial diet at the rate of 0, 100, 200, and 300 mg/kg, respectively during 7 weeks, . At the end of the breeding period, the growth indices including weight gain, food conversion coefficient, specific growth coefficient, specific growth rate, condition factor, protein yield ratio, and survival percentage were examined. In all the growth indices, there was a significant increase in the feeding groups. Gamma-aminobutyric acid supplement compared to the negative control group was observed, the highest of which was related to the treatment of 300 mg of GABA supplement (P < 0.05). The lowest food conversion factor among the experimental treatments was related to the 300 mg group, which had a statistically significant difference with the positive control group (P<0.05, no deaths were observed in any of the groups. The results showed that adding a gamma-aminobutyric acid supplement to the diet of rainbow trout raised in high density moderates the negative effects of stress resulting from high density on growth indicators and improves these indicators.

The aim of this research is to investigate the effects of different levels of olive leaf polyphenol (POL) on salmon. The rainbow is Oncorhynchus mykiss. Number of 120 pieces of fish with an average weight of 6.5 ± 0.1 grams were randomly divided into four treatments with three replications in 100 liter storage tanks and with four diets containing zero, 0.5, 1 and 2 grams (POL) per kilogram. The food was fed for 8 weeks. At the end of the period, growth factors, non-specific immune indices of mucus and serum and the relative expression of immune genes were investigated. Investigation of serum safety indicators, blood sampling from the caudal stem of the treatments was done completely randomly. To measure mucus safety indicators, sampling and collection of mucus from all treatments was done completely randomly. Relative expression of immune genes was investigated from sampled intestinal tissues. The obtained results showed the improvement of growth indices in fish fed with three different levels (POL). In terms of non-specific immunity, the results showed an increase in total serum and mucus immunoglobulin in the groups fed with a diet containing 1, 2 g/kg (POL) (P<0.05). The amount of lysozyme activity of total serum and mucus was also affected by (POL) and fish fed with 1 and 2 grams of (POL) showed a significant increase (P<0.05). The relative expression of the immune gene was also affected by feeding with the above supplement in the mentioned treatments (P<0.05). The highest relative expression of the interleukin gene was obtained in the treatment of 2 g/kg and tumor necrosis factor in the treatment of 1 g/kg (POL). Consumption of 2 g/kg olive leaf polyphenol supplement can have a favorable effect on the growth and rearing quality of trout fry.

Heavy metals are one of the most important polluting sources of aquatic ecosystems, so the contamination of fishes with heavy metals, such as cadmium, can lead to their bioaccumulation in the body of consumers and ultimately the occurrence of various dangerous diseases. The aim of this research was to evaluate the amount of cadmium concentration in the rainbow trout, marketed in Birjand, Iran. For this purpose, a total of 96 samples of muscle and gill tissues of rainbow trout (48 fresh and frozen fish gill tissue samples and 48 fresh and frozen fish muscle tissue samples) were tested. Samples were prepared by wet digestion method and cadmium concentration was measured using graphite furnace atomic absorption spectrophotometer. After the statistical analysis of the data the mean value of cadmium in all samples was measured 0.007±0.003 ppm. The amount of cadmium in gill tissues was higher than in muscle tissues, but this difference was not statistically significant (p<0.05). In addition, the average concentration of cadmium in muscle and gill tissues were significantly lower than international standards (p>0.05). he results of this research showed that, fortunately the rainbow trout marketed in Birjand city is in a favorable condition in terms of the cadmium concentration.

The bacterium Yersinia ruckeri is the causative agent of yersiniosis or red mouth disease, which leads to significant economic losses in aquaculture, especially salmon, worldwide. An infectious disease that leads to a septicemic condition with the condition of the body surface and internal organs. Despite this disease, investigation and its effect on this disease was studied in rainbow trout. This study was conducted on 180 pieces of rainbow salmon randomly weighing (25±2 gr), which were exposed to Y. ruckeri (5% and 10% LC50) for 30 days. Accepts. Results The results obtained with the increase in final weight, growth rate, alanine aminotransferase enzyme, high and low lipoprotein, total immunoglobulin, glutathione peroxidase of rainbow trout decreased and on the other hand with the increase of the drug, aspartate aminotransferase enzyme, total oxidant and Malondialdehyde increased so that there was a significant difference between the control group treated with 5% and 10% LD5 of Y. ruckeri bacteria. Based on the results of this research, the density of bacteria has a negative effect on most of the measured indicators.

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 aim of this study was to investigate the effect of different dietary inclusion levels of replacing natural carotenoids derived from carrot powder (0, 25, 50, 75 and 100%) with synthetic astaxanthin on the carcass quality indices of rainbow trout (Oncorhynchus mykiss). A completely randomized experimental design with 5 treatments and one control treatment, each with 3 replications, was employed in this study. The 306 fish with an average initial body weight of 50±/030 g were randomly allocated to 18 experimental fiberglass tanks. The breeding period was 60 days. At the end of the culturing period the fishes were stored in cold temperature (4°C) for 16 days. The results showed that adding natural carotenoids through carrot powder to fish feed had a significant effect on the carcass quality indices (P<0.05). The rates of TVB-N, TBA, WHC and pH indices in treatments revealed that replacing 50 and 75% natural carotenoids for synthetic astaxanthin in the diet significantly reduce the rate of fish spoilage over the cold storage period (P<0.05).

The use of immune stimulants such as probiotics improves the physiological condition of fish. The aim of this study was to investigate the effect of different levels of prebiotic fructooligosaccharides on the immune parameters of rainbow trout serum and mucus. For this purpose, a number of 120 tilapia fry for 42 days in 4 experimental groups (each group contains 10 fish) with 3 repetitions including: treatment (1) control, without fructolycosaccharide prebiotic, treatment (2) food containing 0.05 treatment ( 3) food containing 0.1% and treatment (4) food containing 0.2% prebiotic were divided. After the end of the feeding period, biochemical indices of fish serum and mucus were evaluated at different levels. The serum immune indices in the treatments fed with probiotics on day 40 were significantly different from the control group (P<0.05). The results of statistical analysis showed that the use of fructo-lycosaccharide had a positive effect on serum immunity indicators and among serum immunity indicators, AST enzyme level, albumin, glucose and total protein showed better effects. Experimental treatments had a significant effect on alkaline phosphatase, lysozyme enzyme, soluble protein and mucus immunoglobulin (p < 0.05), so that the amount of alkaline phosphatase, lysozyme enzyme and soluble mucus protein due to treatments fed with prebiotics and with increasing prebiotic concentration, It increased significantly, but the amount of mucus immunoglobulin decreased due to treatments fed with prebiotic and with increasing its concentration. The general conclusion of this study shows that the level of 0.2% fructolicosaccharide prebiotic on the 40th day can partially strengthen the skin mucus indices and the serum indices of rainbow trout and it was found that the addition of prebiotics to the diet It has a significant effect and strengthens the immune system.

The application of probiotics in aquaculture has been increased in recent years due to the many benefits for fish health. The most important factors in reducing the viability of probiotics during passing through the digestive system are low pH in stomach and proteases and bile salts. Encapsulating of probiotics within biodegradable nanoparticles has been found to increase their viability and efficiency in fish gut. In the current study, the effects of microencapsulation of Lactobacillus rhamnosus by internal emulsification with alginate / chitosan on some of the immunological parameters in rainbow trout (Oncorhynchus mykiss) were evaluated. An experiment was designed with four treatments each with three replicates. 480 juvenile rainbow trout average (±SD) initial weight of 25.53±.82 g was assigned to fifteen experimental tanks. Fish in T1 received Lactobacillus rhamnosus encapsulated by internal emulsification with alginate / chitosan, T2 were fed with alginate/chitosan enriched free probiotic diet, T3 received bacteria without any encapsulation and T4 received basic diet as a control group. All treatments were fed with experimental diets for 60 days. Fish were sampled on days 30 and 60 and some of the immunological parameters consist of Lysozime, Complement, Total protein, Albumin, Globulin and NBT were measured. Results showed that lysozyme in treatment of encapsulated by internal emulsification significantly was higher than other groups at day 30 and 60 of experiment (p<0.05). Also, a significant increase was served in the total protein and globulin in T1 and T2 at day 30 compared to the other groups and at day 60 compared to the control group (p<0.05). Generally, it can be concluded that the microencapsulation of Lactobacillus rhamnosus by internal emulsification with alginate / chitosan has significant effects on some of the immunological parameters in rainbow trout and improved the immune responses in this fish. Results showed that lysozyme in treatment of encapsulated by internal emulsification significantly was higher than other groups at day 30 and 60 of experiment (p<0.05). Also a significant increase was bserved in the total protein and globulin in T1 and T2 at day 30 compared to the other groups and at day 60 compared to the control group (p<0.05).
Generally, it can be concluded that the microencapsulation of Lactobacillus rhamnosus by internal emulsification with alginate / chitosan has significant effects on some of the immunological parameters in rainbow trout (Oncorhynchus mykiss) and improved the immune responses in this 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.

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.

The aim of this research was to investigate the effects of different postbiotic levels on growth indicators, feed consumption and antioxidant defense system in rainbow trout (Oncorhynchus mykiss). For this purpose, rainbow trout fry (2-3 grams) were fed with experimental diets containing different levels (zero (control), 2, 4 and 8 grams per kilogram) of postbiotics for 8 weeks. At the end of the period, the growth indices and serum antioxidant defense system values were measured. Growth indices (average weight, specific growth rate, food conversion ratio, survival rate) were not significantly different between fish fed with postbiotic based on Saccharomyces cerevisiae yeast compared to the control group, although the increase in growth compared to the group The witness was observed. The highest numerical value of growth was obtained in fry fed with 8 grams of postbiotic per kilogram. Also, improvement of food conversion ratio was observed in fry fed with postbiotics. Although statistically, this decrease in food conversion coefficient was not significant. In all antioxidant factors, a significant difference was observed between the control group and the 8 g/kg treatment group. A significant difference was observed in the amount of catalase enzyme between the control group and the treatment group of 2 grams and 8 grams per kilogram. Also, similar results were observed regarding the activity of the superoxide dismutase enzyme, so that a significant difference was observed between the control group and the 8 gram treatment group. Regarding the glutathione peroxidase enzyme, a significant difference was observed only between the control group and the 8g/kg treatment, and the highest amount of this enzyme was observed in the 8g/kg treatment. According to the results of the present study, it can be concluded that the use of postbiotics based on Saccharomyces cerevisiae yeast in the diet of rainbow trout can be recommended to improve the growth indicators and also increase the capacity of the antioxidant defense system in rainbow trout.

The aim of this study was to investigate the potential of using saffron petal powder on the growth performance and innate immune parameters of the skin mucus of rainbow trout. For this purpose, 600 rainbow trout juvenile (6.6 ± 0.19 g) were randomly divided into four experimental groups and fed with diets containing 0, 0.5, 1 and 2% raw powder of saffron petals for 8 weeks. The results showed that feeding juvenile with a diet containing 0.5% saffron petal powder led to a significant improvement in growth indicators including gain weight, specific growth rate and factor condition compared to the control group. The results showed that the juvenile fed with a diet containing 0.5% saffron petal powder led to a significant improvement in growth indicators incliding weight gain, specific growth rate and condition factore feed conversion ratio compared to the control group, while, higher concentrations (1.5 and 2%) had no significant effect on the growth performance. The analysis of the innate immune parameters of the skin mucus also showed lysozyme enzyme had a dose-dependent increase, so that its highest level was observed in the treatments fed with ration containing 2% saffron petal powder. The analysis of the innate immune parameters of the skin mucus also showed that the lysozyme enzyme had a dose-dependent increase, so that its highest level was observed in the treatments fed with a diet containing 2% saffron petal powder. Also, the highest level of hemagglutination activity and antibacterial activity against two common pathogenic bacteria in aquaculture, including Yersinia rookeri and Aeromonas hydrophila, was related to the treatment fed with a diet containing 2% saffron petal powder. Therefore, saffron petal powder, especially at a concentration of 0.5%, has the potential to be used as a growth and immune stimulant with natural origin, cost-effective, efficient, and eco-friendly immunostimulant in rainbow trout farms to improve the level of aquatic health and increase resistance to common bacterial infections, including enteric redmouth disease and bacterial hemorrhagic septicemia.

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.

In order to evaluate the quality of effluent pollutants from the rainbow trout breeding farms in the selected farms of Kohgiluyeh and Boyer Ahmad Province, water samples were taken from five individual farms during the years 2021-2022. The physical and chemical indicators of water including acidity, biological oxygen demand, dissolved oxygen, electrical conductivity, nitrite, nitrate, phosphate, total suspended solids, total dissolved solids, total hardness, alkalinity, iron, oxygen saturation were measured once in each season from the inlet and outlet water (each treatment with 3 replicates). Based on the results, the range of pH changes (5.93-7.29), biological oxygen demand (6.41-7.56 mg/l), ammonium (0-0.319 mg/l), nitrite (0-0.181 mg/l), nitrate (2.19-19.2 mg/l), phosphate (0. 1-0.18 mg/l), total alkalinity (132-238), dissolved oxygen (3.35-8.11 mg/l), electrical conductivity (311-899 microsiemens/cm), TDS (203.7-607.9), and total hardness (312-157.77 mg/l) were obtained. The results showed that the concentrations of ammonium, nitrite, nitrate, phosphate, EC, and total dissolved solids parameters in the effluent compared to the input from the different farms has increased due to the increase of metabolism, fish density, concentration of nutrients, drugs and disinfectants, intensity and speed of water and the oxygen concentration in the effluent of the farms has decreased due to more metabolic activities than the input from the rearing ponds. Also, the amount of biochemical oxygen demand (BOD) and environmental chemical oxygen demand (COD) were increased and the dissolved oxygen was consumed and its amount decreased due to the increase of organic substances, nitrate, and the provision of oxidation conditions.

The aim of present study was production of Fatir bread fortified with rainbow trout and silver carp meats and evaluation of its quality attributes during room temperature storage.

Different concentrations of cooked rainbow trout and silver carp meat (5, 10, 15, 20 and 25%) were added to the Fatir bread and sensory properties of prepared bread were measured. Then, selected treatments were stored for 9 days at room temperature and during this time the quality attributes were evaluated. 

Results of initial sensory evaluations were showed that the Fatir bread containing 5% of rainbow trout and 10% of silver carp were accepted. Results also demonstrated that the protein, lipid and moisture content of the bread were increased with addition of the fish meat. Fatir bread fortified with fish meat had higher TVB-N, peroxide and total viable bacteria during room storage period. In terms of flavor index, the control Fatir bread was acceptable until the end of the storage period, however, the breads fortified with fish meat were within the acceptable range until day 5.

Can be concluded that although fortified breads showed higher nutritional value, they had lower shelf life than control bread. Between fortified breads, the quality changes were lower in the bread containing rainbow trout meat.

Rainbow trout have found a good place in the household food basket due to their valuable nutritional properties. Therefore, supply in the form of hygienic packaging of this product due to CORONA pandemic in the country will be inevitable. This research has been done in order to provide intelligent packaging with the ability to detect microbial spoilage of rainbow trout. Fish fillet was packaged with H2S gas sensor based on FeCl3/Cellulose acetate. These packages were examined for total bacteria, temperatures swing, H2S producing bacteria and Escherichia coli (1×104 CFU/ml) during storage at 25 ° C for 3 days as well as storage at 4 ° C for 16 days. After imaging the correlation, the color changes of the sensor were calculated and evaluated as the color value. Sensor performance in terms of color change was significant (P <0.05) and the correlation between sensor color value and total bacterial growth in a 3-day period was 0.901. In order to accurately identify the growth of Escherichia coli, the correlation of Pearson color value and bacterial growth was equal to 0.932. Also, in the study the correlation between the color value with the number of total bacteria, temperatures swing bacteria and H2S producing bacteria were 0.835, 0.869 and 0.836, respectively. Using a sensor with a combination of iron (III) chloride and cellulose acetate to determine the microbial spoilage of rainbow trout can be used in the future as a consumer-centric quality control method that can be commercialized.