فیل ماهی

Aquaculture is increasingly vital for meeting the protein needs of a growing global population. Successful production relies on efficient feed, which accounts for 60% of costs, and the development of high-quality products. Disease management in aquaculture is challenging due to factors like poor nutrition and environmental conditions, making prevention more critical than treatment (Ndashe et al., 2023). Current strategies focus on using immune stimulants and additives, such as organic acids, probiotics, and prebiotics, to enhance fish health and resilience against diseases (Dawood et al., 2018). The use of natural growth stimulants like chitin, chitosan, and lactoferrin has surged due to their economic benefits and minimal environmental impact. These substances not only improve immune responses but also enhance the antibacterial activity of phagocytic cells, contributing to sustainable aquaculture practices. Overall, the shift towards these natural alternatives reflects a growing recognition of their value in promoting fish health and reducing reliance on chemical treatments. Chitosan is a biodegradable and biocompatible polysaccharide derived from glucosamine through the deacetylation of chitin, predominantly found in the exoskeletons of crustaceans, particularly shrimp shells. It offers numerous benefits in aquaculture, notably enhancing fish health and growth. Chitosan stimulates the immune system by increasing levels of immunoglobulin M (IgM) and lysozyme activity, which improves disease resistance. It also boosts antioxidant capacity by enhancing the activity of enzymes like superoxide dismutase (SOD) and catalase (CAT), thereby reducing oxidative stress. Additionally, chitosan promotes gut health by increasing intestinal villi length and digestive enzyme activity, facilitating better nutrient absorption (Mukarram et al., 2023; Zhang et al., 2024). Moreover, chitosan can chelate heavy metals such as cadmium, mitigating their toxic effects on fish, and its antibacterial properties help maintain gut microbiota balance by preventing pathogenic bacteria while promoting beneficial ones. Overall, dietary chitosan supplementation has been shown to enhance growth, health, and stress resistance in various fish species, making it a valuable additive in aquaculture. In the context of sturgeon (Huso huso) farming in Iran, reducing juvenile fish mortality and increasing growth rates are critical for economic efficiency, highlighting the importance of suitable diets and micronutrient balance to enhance immune function and production efficiency.

The extraction of chitosan from shrimp shells was carried out through four stages: demineralization, deproteinization, decolorization, and deacetylation. 1260 fish (2.87 ± 0.07 g) after passing the acclimatization period, were fed in 18 tanks with six experimental diets, including control diet (without chitosan, T1), 0.15% (T2), 0.3% (T3), 0.45% (T4), 0.6% (T5) and 0.75% (T6) of chitosan (n=3) for 12 weeks. Then all growth indices such as final weight, growth rate, Protein Efficiency Ratio, and FCR, immunological parameters like lysozyme, ACH50, total immunoglobulin, and IgM were measured. The body composition also was measured after 12 weeks.

The final body weight and body weight gain in treatments containing 0.45%, 0.6%, and 0.75% chitosan were significantly higher compared to the control, 0.15% and 0.3% chitosan treatments. The specific growth rate significantly increased with the higher levels of chitosan, and no significant difference was observed in the group fed with 0.15% chitosan compared to the control group. The hepatosomatic index significantly improved in all chitosan-fed treatments compared to the control group (P≤0.05). The feed conversion ratio significantly improved with increasing levels of chitosan compared to the control group. The protein efficiency ratio also increased in the treatments fed with 0.45%, 0.6%, and 0.75% chitosan compared to the control group, but no significant differences were found in the treatments fed with concentrations of 0.15% and 0.3% chitosan (P≥0.05). The lowest carcass protein level was observed in the control treatment, which showed a statistically significant difference compared to the carcass protein levels of other treatments, except for the 0.15% chitosan treatment (P ≤ 0.05). The carcass protein levels in the 0.45%, 0.6%, and 0.75% chitosan treatments were the highest, but no significant differences were observed among them. The carcass fat level in the 0.45%, 0.6%, and 0.75% chitosan treatments was significantly lower compared to the control group (P≤0.05). With the increase in chitosan concentration in the diets, the serum lysozyme levels significantly increased except for the group consuming 0.15% chitosan (P≤0.05). The results obtained from the complement activity (ACH50) measurements showed that with the increase in chitosan levels in the diet, this indicator significantly increased in the serum (P≤0.05). The total serum immunoglobulin and IgM levels, also increased significantly compared to the control group (P≤0.05).

Chitosan, has gained attention in aquaculture for its potential as a growth promoter and immunostimulant. Research indicates that dietary chitosan enhances growth performance, feed efficiency, and immune responses in various fish species, including Nile tilapia, common carp, and golden pompano. Optimal chitosan levels, typically ranging from 0.5% to 2%, have been shown to improve weight gain, feed conversion ratios, and overall health status by promoting gut health and enhancing digestive enzyme activities. Studies also highlight chitosan's role in modulating serum biochemical parameters, reducing fat accumulation in the liver, and improving intestinal morphology. The balance of chitosan dosage is crucial, as it can enhance beneficial bacteria while inhibiting harmful ones, thereby supporting the fish's immune system. Overall, chitosan represents a promising, eco-friendly alternative to antibiotics in aquaculture, contributing to sustainable fish farming practices while improving the health and productivity of cultured species. Chitosan also enhances nonspecific immunity and reduces mortality in fish, as evidenced by studies on common carp (Maqsood et al., 2010). However, its effects on feed consumption and conversion ratios can vary, with some studies showing no significant impact on these parameters despite improvements in liver health (Stanek et al., 2023). Overall, chitosan's role in aquaculture highlights its potential as a dietary supplement to improve fish health, growth, and resistance to environmental stressors. Serum parameter measurements are crucial for assessing the metabolic and physiological health of fish, particularly in aquaculture where they are susceptible to opportunistic bacterial infections. Lysozyme activity, an indicator of immune health, was found to increase with dietary chitosan levels. Research indicates that chitosan enhances lysozyme activity across various fish species, including loach, cobia, silver carp, vannamei shrimp, and rainbow trout. Additionally, chitosan supplementation in diets for beluga sturgeon and hybrid sturgeon also boosted lysozyme levels. Chitosan's immune-boosting effects are attributed to its ability to scavenge free radicals, enhancing innate immunity. Complement activity, vital for non-specific immune responses, also increased in fish like Nile tilapia and mrigal when fed chitosan. However, responses to chitosan vary by species and concentration, with some studies indicating potential negative effects at higher doses. Furthermore, IgM levels, a key immunoglobulin in fish, significantly increased with chitosan supplementation, reinforcing its role in adaptive immunity. Overall, optimal chitosan levels in fish diets can significantly enhance immune responses and health. The increase in IgM levels with dietary chitosan is not fully understood, necessitating further research to clarify the mechanisms involved (Salam et al., 2024). Studies indicate that chitosan enhances IgM and total protein levels in fish, such as rainbow trout and golden pompano, although excessive chitosan (10 g/kg) can reduce these benefits (Yu et al., 2023). In tilapia, IgM levels increased significantly up to 1.5% chitosan but decreased at 2% (Zhang et al., 2024). Additionally, recombinant chitosan nanoparticles show promise as alternatives to antibiotics in aquaculture, potentially enhancing disease resistance. This research supports using chitosan in beluga fry diets to improve growth and immune performance while reducing antibiotic reliance, particularly at levels of 0.45% to 0.6%, which positively affected growth, body composition, and immune parameters.

AbstractThe study investigated the effects of substituting fishmeal with different levels of hydrolyzed protein on the serum biochemical composition and immune system of beluga (Huso huso) fry over a 48-day period. A total of 750 fish were randomly assigned to five groups: a control group (no hydrolyzed protein), three groups with varying levels of hydrolyzed protein (2.75%, 5.5%, and 8.25%), and a positive control group (commercial feed). The study found significant differences in glucose levels among the groups (P<0.05), with the control group having the highest glucose level. Treatment 2 had the highest total protein and lipid levels, which significantly differed from the other groups (P<0.05).  Liver enzyme levels (ALT, AST and ALP) did not vary significantly among the groups (P>0.05).  There were no significant differences in cholesterol levels (P>0.05). Regarding immune factors, treatment 2 exhibited significantly higher total immunoglobulin levels compared to all other groups except for treatment 3 (P<0.05). Lysozyme levels did not differ significantly between the control group and treatments 1, 3, and 4 (P>0.05); however, treatment 2 displayed the highest level. IgM and ACH50 activity did not differ significantly across all groups (P>0.05). In conclusion, replacing fishmeal with hydrolyzed protein at a concentration of 2.75% to 5.5% improved performance in blood biochemical and immune parameters of beluga fry when compared to the control group.

The aim of this study was to investigate the effect of in fall and winter on the hematological and serum biochemical factors of 3-4 years old great sturgeon in the penclture ) located in the Gorgan Bay (Caspian sea) and processing sturgeon center of Marjani for 6 months.  Huso huso individuals were anesthetized withclove powderand 5 mL of bloodwas sampling from a total of 15 great sturgeon specimens were apparentlyhealthy by caudal venous puncture each of the examined panes (3 pins)in different seasons.Blood was analyzed with routine method and standard formulas used in fish hematology. the results showed thatthere are no any differences between the mean corpuscular volume, cortisol levels and activity of Alanine aminotransferase enzyme in the different season(p>0.05).But, by examining other parameters, the highest WBCs number, Activity of aspartate aminotransferase and alkaline phosphatase enzymes in summer, the highest RBCs number, hematocrit concentration, total serum protein in spring, the highesthemoglobin concentration, the mean corpuscular hemoglobinand themean corpuscular hemoglobin concentration in autumn and the highest glucose levels in winter were observed, which were significantly increased in comparison with other seasons (p<0.05). Overally, based on these results, it can be rectified that temperature changes as a result of season transition may have an important role on Blood factors of Huso huso. As with the same ecological conditions, with changing the temperature of the environment, we will see different changes in the blood factorsin the Beluga.

Fishmeal price were increasing every year and predicted that fish diet will have a wider range of ingredients replaced by fishmeal, such as vegetable sources, microbial protein sources, waste from fishing and animal protein waste (Glencross et al., 2007). Vegetable proteins can replace fish meal to some extent and have a negative effect on the growth of aquatic animals at high levels. But many studies have shown that a mixture of vegetable proteins can improve the amino acid profile compared to single protein source replaced by fish meal (Amaya et al., 2007).  By this method, high replacement with a blend of protein Vegetables have been reported in aquatic animal (Hansen et al., 2007), but increasing fiber, increasing carbohydrates and inappropriate amino acids in diets based on animal and vegetable proteins can led to a negative effect on fish digestive system that showed by growth reduction, immune system depress , low quality meat and even fish fatality in a long-term feeding period (Raskovic et al., 2011). therefore, in this experiment, the effect of a mixture of animal and vegetable proteins replaced by fish meal (levels of 20, 40, 60 and 80%) on the growth indices and digestive system tissue Huso huso were studied.

In order to reduce the share of fishmeal in the diet of beluga, a basal diet based on 54% of fishmeal was made. A mixture of animal and vegetable proteins (corn gluten: 35%, wheat gluten: 19.34%, processed soybean flour: 3%, chicken by-products: 20%, meat and bone meal: 8%, blood meal: 3.4%) at 20, 40, 60 and 80% levels replaced with fishmeal (FM) (CGM20, CGM40, CGM60, and CGM80, respectively) and finally 5 isonitrogenous (44% crude protein) and isoenergetic (18 MJ/kg) diets were produced. The fish (Average weight: 167±6.5 gr) were fed to saturation for 12 weeks.  Biometry were carried out on month interval and by carrying out information obtained from fish length, weight and food consumption, growth indices and feed efficiency ratio were calculated. At the end of the feeding period, 30% of the fish population was collected from each tank for histological studies. Three parts of the intestine (hindgut, midgut, and foregut) were removed. It was fixed and stained. Histological studies were carried out by an optical microscope equipped with a monitor.

There was no significant difference in the final weight and length of fish of different treatments (P>0.05). condition factor and percentage of weight gain of fish fed with FM, CGM20, CGM40, CGM60 and CGM80 had no no significant difference and percentage of weight gain was close to each other (243 to 298%) (P>0.05). No significant difference was observed in specific growth rate and daily growth rate and food conversion ratio in fish fed with all diets (P>0.05). Fish fed FM had the highest protein efficiency ratio (1.75±0.23), but protein efficiency ratio in fish fed with CGM20, CGM40, CGM60 and CGM80 was in the range of 1.53 to 1.73%. But no significant difference was observed (P>0.05). Histological studies were carried out by an optical microscope equipped with a monitor. The intestinal tissue of fish fed with CGM80 diet had necrosis and biliary stagnation. However, histological studies in fish fed with FM, CGM20, CGM40, and CGM60 diets showed that the lamina propria space is adequate, the necrosis of enterocytes is negligible, and the number of goblet cells in the anterior, middle, and distal intestine is balanced. The final results confirmed that the CGM80 did not a negative effect on the growth fish, but it caused damage to the digestive system.  In the present study, there is no significant difference in growth indices and food conversion ratio of fish fed with diets based on fish meal and diets based on corn gluten flour (a mixture of corn gluten: 35%, wheat gluten: 19.34%, soybean meal processed: 3%, poultry by product: 20%, meat and bone meal: 8%, blood powder: 4.3%). In this order, it seems be that alternative diets formulation based on a mixture of Animal and vegetable protein sources  were led to enriching of profile and biochemical composition of diet, In addition beluga Compared to white and Siberian sturheon is a species that can be fed with high carbohydrates percentages without growth reduction (Mohseni et al., 2011). In the present experiment, by increasing mixtures based on corn gluten-based in fish diet,  goblet cells were increased and reached to highest value in CGM80. goblet cells are related to immune system and mucus secretion in order to fluidity of digestive tract and create a protective barrier against mechanical and chemical damage (Marchetti et al., 2006). it seems that the increase of goblet cells in beluga fed with a mixture of vegetable proteins (CGM60 and CGM80) is a reaction against to mucous layer necrosis and reduction of intestinal villi in order to further damage of folds by secreting more mucins (Li et al., 2007), but in general, digestive tract epithelium damage in fish fed CGM20, CGM40 diets and CGM60 was negligible compared to fish fed with FM diets and did not lead to enteritis (intestinal inflammation). Therefore, it is suggested to replace fishmeal with a mixture of animal and vegetable proteins at 20 and 40% in Huso huso diet during the fattening stage.

Aquaculture development is challenged with limitation and high costs of supplying protein diets, so searching for alternative protein sources in fish diets is inevitable (Tacon, 2020). Insect meals are considered as a promising substitution protein ingredients last decades (Alfiko et al., 2022). Among candidates’ insect meals, Silkworm is well-balanced in protein as well as lipid and can be served as feedstuff (Mahanta et al., 2023). A study conducted to investigate if low level of silk worm pupa inclusion in fingerling Beluga sturgeon (Huso huso) diet could provide a protein source replacement accompanying with high benefit for the species.

Fingerling Beluga sturgeons (5±0.2 g, mean±SE) fed with experimental diets for a period of 8 weeks. Four experimental diets includes: no (SWP) inclusion as a control treatment (T0), 5, 10 and 15 percent (SWP) substitution referred as (T5, T10 and T15) treatments. At the end of the experiment, Weight Gain (WG), Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) calculated to assess the diets quality on fish production. Hepatic enzyme (ALP, AST, and ALT) and serum biochemical (IgM, total protein and lysozyme) analyzed for revealing the health status of fish.

(SWP) treatments, in particular (T15) had a significant increase in (WG) compared to the control group (p<0.05). (SGR) as well as (CF) in (SWP) treatments showed no significant differences compare to the (T0) (p<0.05). (FCR) was significantly improved among (SWP) treatments, although the difference was not significant (p<0.05). Serum lysozyme, Serum immunoglobin and total protein in (T10) and (T15) were significantly increased compared to the control group, (T0) (p<0.05).

Our findings indicate the protein level adjusts and fixes with the (SWP) was efficiently enough to be replaced with fish meal in fingerling Beluga sturgeon (H. huso). The results of (SGR) as well as (CF) suggest that the replacement level could be changes to more to get a differently improved result. Hepatic enzymes showed that (SWP) did not affect impairment in digestive tract.  What’s more, blood biochemical analysis showed that (SWP) can have immunomodulatory effects on fingerling Beluga sturgeons (Zhou et al., 2022)

The aim of the research was to determine the effect of feeding frequency on growth indicators, carcass composition, activity of some digestive enzymes and survival of beluga (Huso huso) larvae. For this purpose, the total number of 10800 beluga larvae, with initial weight of 0.048+0.001 g, were randomly stocked in 36 500-liter fiberglass tanks containing 100 liters of well water, for 31 days with a feeding frequency of 6 and 12 times a day using Artemia nauplii, Artemia biomass, Daphnia, chironomid larvae and formulated diet were reared. The results showed that, feeding larvae with chironomid larvae or Artemia biomass, could increase the survival rate and weight of larvae, respectively. The survival percentage of the treatments on different days after hatching of the larvae during 12 times of feeding per day in most treatments was significantly higher than that of 6 times of feeding per day (p<0.05). The average weight of larvae in different treatments, when feeding 12 times a day compared to feeding 6 times a day, had no statistically significant difference (p>0.05). In most treatments, carcass protein content of larvae, during 12 and 6 times feeding a day, had no statistically significant difference (p>0.05). But the carcass fat content, during 12 times feeding per day in half of treatments, was significantly higher than 6 times feeding per day (p<0.05). The activity of pepsin, trypsin and lipase enzymes, during 12 times feeding a day was significantly more than 6 times a day feeding. Totally, feeding larvae 12 times a day was preferable to feeding 6 times a day, based on improvement of survival of larvae, condition factore and activity of enzymes.

Studies on nutrient utilization and growth performance of Beluga (Huso huso) raised on five feeding schedules (treatment 1 continuously fed plant protein diet, treatment 2 continuously fed fish meal diet, treatment 3 alternate feeding of a 1-day plant protein diet; followed by a 1-day fish meal diet, treatment 4 plant protein diet in the morning fallowed by fish meal diet in the afternoon and treatment 5 fish meal diet in the morning followed by plant protein diet in the afternoon) in 3 replication (20 fish in each repetition) under laboratory conditions showed that continuous feeding with Fish meal diet (treatment 2) resulted in maximum growth, which was not significantly different from treatments 4 and 5 (p<0.05). While feeding with plant protein diet (treatment 1) and feeding every other day (treatment 3) led to a decrease in fish growth performance (p<0.05). In terms of protein digestibility, the best treatments were 2, 4 and 5, which did not show any significant difference with other treatments (p<0.05). The highest amount of muscle arginine belonged to treatments 2, 4 and 5, which was significantly higher than muscle arginine of fish fed with treatments 1 and 3 (p<0.05). Also, the highest amount of glycine was observed in treatment 5, which was not significantly different from other treatments except treatment 1. No significant difference was observed in the amounts of other muscle amino acids of the experimental treatments (p<0.05). The obtained results showed that the alternating change of the dietary protein source during one day (morning and evening and vice versa) does not have any negative effect on the growth performance and feed efficiency, and in most of the nutritional factors, it is equal to the treatment fed with fish meal.

The effect of inclusion of Nanoselenium to the commercial diet on the growth indices, liver enzymes and immune system of juvenile Acipenser stellatus was investigated. Individual 120 juveniles with an average weight of 21.93±1.03 g were fed with diets A, B, C and D (containing 0.1, 0.2, 0.3 and no Nanoselenium) for 8 weeks. At the end of the rearing period, blood samples were prepared from fish to evaluate liver enzymes and immune system indices. The final weight and daily growth in fish fed with diet A (0.1 mg /kg) were significantly higher than those fed with diet C (0.3 mg/kg). But there was no significant difference with fish fed with diet D (non Nanoselenium). The condition factor and protein efficiency ratio of fish fed with diet containing 0.1 mg/kg Nanoselenium was significantly higher than fish fed with diets C and D. There was no significant difference in the of total immunoglobulin (IgM) and complement (ACH50) in different groups, But the secretion of lysozyme in fish fed with diet B was significantly higher than other groups. There was no significant difference in the activities of alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase enzymes in fish fed with diets containing Nanoselenium compared to the treatment without Nanoselenium. It seems that inclusion of 0.1 and 0.2 mg of Nanoselenium per kilogram has a positive effect on the growth indices and immune system of Acipenser stellatus in growth stage.

This study aimed to evaluate the effects of feeding with different types of live feeds on growth performance, survival rate, body composition, and fatty acids profile of great sturgeon (Huso huso) larvae during short-time weaning to dry feed. A total of 1200 great sturgeon larvae with a mean initial weight of 0.43±0.01g were distributed randomly into twelve 80-L circular fiberglass tanks (100 larvae per tank) with three replicates. Afterward, the fish were fed with frozen chironomid larvae (T1), frozen Artemia biomass (T2), and a combination of them (T3). The control group © received only a commercial dry feed (0.5 mm: protein 55.59%, lipid 21.12%, ash 11.76%, and moisture 7.96%) throughout the feeding trial. For weaning, the live feed was reduced by 15% every two days, and the dry feed ratio was also gradually increased. According to the results, the final weight (4.99±0.16g), weight gain (4.57±0.17g), body weight increase (1081.53±72.75%), and specific growth rate (11.75±0.29%/day) were significantly higher in T1 than in other groups (p<0.05). The survival rate (56.50±1.32%) significantly decreased in the control group © (p<0.05); however, no mortality was observed in the group fed chironomid larvae (p<0.05). The crude lipid (1.32±0.08%) and moisture (80.98±0.17%) levels of T1 were higher than other groups, and the crude protein content was significantly higher in T3 (11.26±0.39%) and C (11.44±0.44%) than T1 (9.23±0.39%) and T2 (9.67±0.28%) groups (p<0.05). There was a significant decrease in total n-3 LC-PUFA fatty acids (9.53±0.04%) in T3 than in T1 (11.02±071%) (p<0.05). The EPA/DHA ratio in T1 was significantly higher (0.45±0.03%) than other treatments (p<0.05). Consequently, the administration of frozen chironomid larvae is recommended during a 21-day adaptation period of great sturgeon larvae to the dry feed, due to the optimizing effects on growth indices, survival, and fatty acid contents.

A study was carried to determination effect of recycle water on growth indices and some blood parameters of farmed Huso huso  n a completely randomized design including 50% inlet water and 50% return water (R50), 20% inlet water and 80% Return water (R80) and no return water (R0)  respectively. A total of 180 farmed Huso huso with an average weight (6162/71± 66/68) were selected and reared in 9 concrete ponds for 8 months. Biometry was carried out each month and Blood samples were taken from fish in the end of period rearing. At the end of rearing period, the highest mean final weight (13908.15 ±3.79 g), body weight gain percentage (129.4 ± 8.75%), specific growth rate (0.34 ± 0.02) and condition factor (0.72 ± 0.01) and the lowest feed conversion ratio (2.64 13 ±0.13) was observed in the fish group of 80% recycle water (R80) which had a significant difference with the fish belonged no water recycle (R0). (P <0.05). The results of blood parameters indicated that percentage of white blood cells and neutrophil in R80 treatment was significantly higher than R50 and R0 (P < 0.05). According to the obtained results, it can be suggested that Huso huso culture in fattening up to the pre-breeding stage (14 kg) using recycle water system not only does not led to reduce growth and hematological damage, but also improves water productivity and increases production efficiency.

The basis of biofloc technology is biomaterials, dead organic particles, microbes, algae, protozoa and other organisms. The present study was conducted to evaluate the effect of biofloc system on blood indices in juvenile H. huso in the International Sturgeon Research Institute of the Caspian Sea during one year. For this purpose, 120 fish with an initial weight of 168.2 ± 2.9 g were introduced in 6 fiberglass tanks with volume 2000 liter. Treatments included control treatment and one biofloc treatment and each treatment had 3 replications. During the experiment blood and immunological indices of fish were measured. In terms of blood indices, biofloc treatment was better. The lowest number of white blood cells, neutrophils and the highest number of red blood cells, hematocrit and Measn corposcular volume (MCV) were observed in the biofloc treatment and there was a significant difference with the control treatment (P<0.05). Immunological results showed the levels of immunoglobulin M, lysozyme and total immunoglobulin in biofloc treatment improved compared to the control, but were not significant difference (P <0.05). In addition, biofloc treatment had more bacteria than the control and showed a significant difference (P<0.05). Therefore, biofloc treatment can be selected as the superior treatment according to its performance. Because it improved the conditions and increased the efficiency of the breeding system and also improved the living conditions.

The present study was performed to investigate the effects of using chicken abattoir waste powder instead of fish powder using dietary supplement (garlic powder) in the diet of Huso huso with an average initial weight of 50.66 ± 1.5 g, on the index. Growth, carcass composition and digestibility were examined in a completely randomized design with 8 treatments, each with 3 replications for 12 weeks. The treatments included four levels of replacement of fish meal with chicken abattoir waste powder (0, 50, 75 and 100%) and application of two levels of garlic powder (0 and 2%). G: 2% garlic, PG treatment 50: 50% waste + 2% garlic, G treatment 50: 50% waste, PG treatment 75: 75% waste + 2% garlic, G treatment 75: 75% waste, PG treatment 100: 100% Lesions + 2% garlic and G 100 treatment: 100% lesions were named. Treatments containing garlic powder showed a significant increase in weight gain percentage, daily growth and specific growth coefficient compared to treatments without garlic powder. With increasing the level of waste replacement, liver index increased significantly so that the highest liver index was related to 100% waste replacement treatments (100G and 100PG) which showed a significant difference with other experimental treatments (p <0.05). The feed conversion ratio in G treatment had the lowest rate which showed a significant difference compared to other treatments (p <0.05). The results of the main and interaction effects of garlic powder and replacement of chicken slaughterhouse waste showed that their interaction did not cause a significant difference between treatments except in feed conversion ratio index (p> 0.05). The use of garlic did not cause a significant difference in the amount of carcass composition (p> 0.05). However, replacement of the lesions caused a significant difference in the amount of carcass composition (p <0.05). With increasing levels of waste replacement with or without garlic in the diet, a significant decrease in protein digestibility has been observed. But fat digestibility was improved by adding garlic. According to the results, it can be said that the replacement of chicken slaughterhouse waste up to 50% in the elephant fish diet did not have destructive effects. And with the addition of 2% garlic powder, the studied indices improved, but the use of higher levels had adverse effects on some factors.

Thiamine, or vitamin B1, is an important coenzyme in lipid, carbohydrate, and protein metabolism that plays a vital role in the embryonic stages and larval development. To evaluate the effects of thiamine on incubation indices of beluga Huso huso, eggs obtained from farmed males and females after fertilization were immersion in water-soluble thiamine with four treatments and two replicates including control (0 mg thiamine per liter of water), T500 (500 mg thiamine per liter of water), T1000 (1000 mg thiamine per liter of water) and T1500 (1500 mg thiamine per liter of water) during water hardening for 30 minutes. Then, eggs were washed five times with fresh water and kept in special incubators until hatching. Incubation indices and larval growth were investigated 24 hours after fertilization to 44 days after starting feeding. Results showed the highest and lowest egg survival at 24 hours after fertilization until hatching were observed in T1500 and control, respectively (P<0.05). At the start of the feeding the results showed no significant difference in larval weight and length (P>0.05). However, thiamine increased the weight, length, and weight gain in T1000 and T1500 at the end of the experiment (P<0.05). Egg immersion in soluble Thiamine led to an increase in the specific growth rate and body weight in T1000 and T1500 at day 36 after the start of feeding (P<0.05). The food conversion ratio, protein efficiency ratio, and lipid efficiency ratio significantly decreased in control and T500 compared to other treatments (P<0.05). The lowest larval survival was observed in control at the beginning of feeding until day 44 (P<0.05). The results of this study indicate that immersion of eggs in thiamine solution can increase larval growth and survival. Therefore, it is recommended that beluga eggs immersion in thiamine solution at least 1000 mg L-1 thiamine after fertilization

The aim of this study was to investigate the physiological response of young beluga to different levels of sodium butyrate in the diet. For this purpose, 360 young beluga (average weight of 15 ± 0.56 g) with 6 experimental diets containing 0, 0.1, 0.2, 0.3, 0.4 and 0.5% sodium butyrate were fed for 8 weeks. The number of red blood cells (RBC) and MCV, MCH and MCHC indices were significantly higher in the 0.3% treatment than in the other treatments (p <0.05). The number of white blood cells (WBC) and the amount of hemoglobin and hematocrit in fish fed with 0.3% sodium butyrate in the feed were higher than other treatments, although there was no significant difference with the treatment of 0.4% and the control group (p >0.05). Lysozyme activity and IgM level in 0.3% treatment was significantly higher than other treatments (p <0.05). Cortisol and glucose levels in fish fed diets containing 0.3% sodium butyrate increased slightly less than other groups after acute density stress and a significant difference was observed between treatments (p <0.05). Overall, this study indicates that including 0.3% sodium butyrate in the diet of young beluga can improve fish health, innate immune response and resistance to density stress.

Rearing of sturgeon is of great importance in Iran, and diet is one of its important factor. A lot of research has been executed on the nutrition of these fish, but more researches are needed to complete this knowledge. The purpose of this research was to investigate the effect of adding glycine to the diet on hematological parameters, protein concentration and plasma enzyme activity in beluga (Huso huso). For this purpose, the fish were fed diets enriched with 0 (control), 0.25, 0.5 and 1% glycine for 8 weeks. The results showed that the number of red blood cells, hematocrit percentage and hemoglobin concentration in 0.25% and 0.5% glycine treatment were significantly higher than the control (P < 0.05). Also, these treatments had lower alkaline phosphatase and aspartate aminotransferase activities than the control (P < 0.05). 1% glycine treatment showed a significant increase in total plasma protein concentration, compared to the control treatment (P < 0.05). Also, there was no significant difference in MCV, MCH, MCHC, albumin, globulin, ammonia, and alanine aminotransferase and lactate dehydrogenase activities among the treatments (P > 0.05).. Based on these results, adding 0.25-0.5% glycine to the diet of beluga can improve hematological indicators.

In the present study, the physical and chemical factors including optimum temperature and pH, the effect of inhibitors, metal ions, oxidizing agents, and surfactants were assayed on the chymotrypsin activity from beluga (Huso huso) intestine. According to the obtained results, the optimum temperature and pH of the chymotrypsin were recorded at 50°C and 8, respectively, and its activity was extremely decreased at temperature>50°C. Inhibitors including SBTI, TLCK, PMSF, ρ-aminobenzamidine, TPCK, pepstatin A, iodoacetic acid and EDTA significantly inhibited the enzyme activity that PMSF, SBTI and TPCK had a completely inhibition effect on the enzymatic activity (P<0.05). The enzyme activity was significantly increased in the presence of Ca+2 and Mg+2 and decreased by Cu+2, Ba+2, Co+2, Zn+2, Fe+2 and Al+3 (P<0.05). Na+ and K+ did not show any significant effect on the activity of enzyme (P>0.05). The enzymatic activity was significantly increased in presence of surfactants including saponin and sodium cholate and showed a significant decrease in presence of SDS and oxidizing agents like sodium perborate and hydrogen peroxide (P<0.05). Therefore, the results of this study showed that the chymotrypsin activity from beluga intestine had a significant decrease in presence of inhibitors, metal ions (except for Ca+2, Mg+2, K+ and Na+), SDS, sodium perborate and hydrogen peroxide and showed a significant increase in presence of Ca+2 and Mg+2, saponin and sodium cholate that it can be affected the maximum activity of the enzyme in digestive physiology of the beluga.

In this study, the effect of Ethylenediaminetetraacetic acid (EDTA) was evaluated on growth performance and body composition in beluga (Huso huso) juveniles. For this purpose, a total of 225 beluga juveniles with initial weight 38.47 ± 0.58 gr (Mean ±   Standard Division) were fed with five treatments with three replications including 0 g/kg EDTA (Control, C), 5 g/kg EDTA (EDTA 5), 10 g/kg EDTA (EDTA 10), 15 g/kg EDTA (EDTA 15), and 20 g/kg EDTA (EDTA 20) for 8 weeks. At the end of the feeding trial, growth performance and body composition were investigated. The results showed that EDTA different levels have a significant effect on final weight, weight gain, and specific growth rate (p < 0.05).  The highest final weight, weight gain, and specific growth rate were observed in EDTA10 and EDTA15 treatments. The lowest final weight, weight gain, and specific growth rate obtained in the control group. The results of body composition analysis at the end of the feeding trial showed that no significant difference was observed in protein, ash, moisture, lipid, and dray mater between treatments (p > 0.05). The present study showed that feeding fish with the 15 gr/ kg diet EDTA improved growth and health.

Sturgeons are known as one of the most valuable fish species in the Caspian Sea and other water bodies across the world. These fishes are highly important both in caviar production and by-products such as leather from the skin. 17 out of 24 sturgeon species are categorized in critically endangered species based on the IUCN red list and all of the five available species in the Caspian Sea have this situation. The most important reasons for the sharp reduction of the sturgeons are illegal haunting for Caviar extraction, loss of nursery grounds, diminishing the water flow from the rivers and water pollution. Sex determination of these fish species is usually time-consuming and invasive, and genetic markers based on traditional methods were not able to solve this problem. Hence, the sex determination of sturgeons in early stages is possible now using the molecular markers obtained from modern techniques, which can be of great importance in terms of aquaculture management in sturgeon farms.

This study aims to compare effects of sources levels of zinc on growth and carcass quality, some haematological and serological indices of juvenile beluga sturgeon, Huso huso (Linnaeus, 1758). A number of 315 juvenile beluga sturgeon (8.4±0.29) were fed in 21 500 lit fiberglass tanks (15 fish per tank) under 7 experimental diets including 1 control diet plus 6 diets containing zinc (mg per kg of diet) in two forms of mineral (zinc sulfate) (ZnSul15, ZnSul30, and ZnSul60 treatments) and organic (chelated with methionine) (ZnMet15, ZnMet30, and ZnMet60 treatments) with three replications per treatment for 12 weeks. The best values of final weight and feed conversion ratio were observed in the ZnMet15 and ZnMet60 treatments. Red blood cells, hemoglobin, and hematocrit showed an incremental trend influenced by increased zinc supplement. Increased carcass protein in the ZnMet30 treatment was significant compared to the control, ZnSul15, and, ZnSul30 treatments (P≤0.05). Reduced carcass lipid in the ZnSul30 and ZnSul60 treatments was significant compared to the other treatments (P≤0.05). Serum triglyceride and cholesterol decreased in the ZnMet treatments compared to the control treatment. Reduced serum glucose in the ZnMet15 and ZnMet60 treatments and also increased serum lysozyme in the ZnMet30 and ZnMet60 treatments were significant compared to the control treatment (P≤0.05). Results demonstrated that most of the indices had better performance in the ZnMet treatments comparted to the other treatments and are proposed as an optimal diet for juvenile beluga sturgeon.

In the present study, the effect of various feeding strategies during 60 days and subsequent re-feeding over the next 60 days was evaluated to achieve the compensatory growth on growth performance and biochemical parameters in great sturgeon Huso huso. For this purpose, two hundred and forty fish with a mean individual weight of 67.10 ± 1.10 g (Mean ± SD) were divided into four feeding strategies groups: satiation feeding (100%), 75% satiation feeding (75%), 50% satiation feeding (50%), and 25% satiation feeding (25%). In the second phase, all groups were fed to satiation. Blood sampling was performed at the end of feeding trial (120 days) to measure biochemical parameters. At the end of first phase, final weight in the satiated group (100%) was higher than the other groups while it decreased with increasing dietary restriction (p < 0.05). Specific growth rate and mean individual weight increased significantly in 75% and 100% satiation feeding compared to the other treatments (p < 0.05). At the end of second phase, there was not significant differences in the final individual weight, total length, weight gaine and specific growth rate among treatments (p > 0.05). Hematocrit was affected by dietary strategies and in the treatment with 25% satiation feeding was lower than the other treatments (p <0.05). Total protein and triglyceride in 100 and 75% treatments were higher than the other treatments (p < 0.05). Based on the present study, feeding, at the rates of 75 and 50% satiation and subsequent re-feeding lead to a high growth rate and reducing the feed costs without negative impact on physiological conditions of the great sturgeon fish, and this methods can be considered as an appropriate strategy for culture of this fish.