abdolmajid hajimoradlou

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 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.