m. sudagar

Researchers have used phytochemicals as sustainable and valuable additives to improve reproduction traits and stimulate the immune system in farm-raised fish species followed by minimizing environmental and public health risks. In this regard, phytochemicals are plant-based bioactive compounds and are known as secondary metabolites. They contain various compounds with a remarkable potential to influence the reproductive performance of aquatic animals. Phytochemicals offer a promising approach to regulate reproductive performance and improve productivity in intensive aquaculture. According to the growing demand for eco-friendly solutions, phytochemicals reduce oxidative stress and enhance disease resistance in different farm-raised fish species. They have various bioactive compounds with unique physiological effects, especially on the reproductive performance of aquatic animals. However, the exact mode of action of these additives on aquatic reproduction traits is not yet well-documented. Overall, phytochemicals can be used as a practical alternative to synthetic additives and have the potential to promote sustainability in different aquaculture sectors around the world based on the availability and affordability of medicinal plants in the region. Polyphenols, flavonoids, isoflavones, anthocyanins, phytoestrogens, terpenoids, carotenoids, limonoids, phytosterols, and glucosinolates are well-known phytochemical molecules with innumerable properties in the host such as antibacterial, antiviral, antioxidant, and anti-inflammatory activities. These compounds are commonly administered orally in aquatic animals. Notably, plant extracts containing bioactive compounds like saponins and flavonoids play a vital role in inducing sexual inversion and fertility disorders. However, the concentration of phenolic compounds varies depending on the herbal genetics (genus, species, cultivar, and genotype), plant extraction methods, environmental conditions, and aquatic animal maturation status. Most studies declared that phytochemicals have a profound effect on fish reproduction due to their various bioactive compounds. They can also induce sexual maturation by interacting with hormone receptors, promote gonadal development by stimulating gonadotropin production, improve sperm quality through antioxidant properties, modulate hormone levels, and support reproductive behavior. However, the effects vary based on fish and plant species, dosage, and exposure duration. Further research is needed to optimize the use of phytochemicals in improving reproductive performance in farmed fish.

The purpose of the present research was to investigate the effects of adding calcium carbonate nanoparticles to the Macrobrachium nipponense diet in the biofloc system under zero exchange conditions. Oriental River prawn (inital weigh of 0.82 ± 0.07 g) were divided into four groups and fed four levels of calcium carbonate nanoparticles as following 0, 25, 50 and 100  mg kg−1 diet in biofloc system (CN0, CN25, CN50, and CN100) for 28 days. This study was applied complete randomized design with three replications. Water quality parameters were measured during the test period. Feed and growth parameters and some metabolic activities of hepatopancreas were measured. Physico-chemical water factors were in the appropriate range for this species. The concentrations of total ammonia nitrogen (TAN), nitrite, and nitrate were not significantly different between the experimental groups. The growth of prawns was significantly higher and feed conversion ratio was lower in CN25 and CN50 groups compared to the control group. The lowest AST and ALT activities were observed in CN25 and CN50 groups compared to the control. The prawns fed with experiment diets had significantly higher total protein, hemocyanin, glucose, and calcium compared to the control. Overall, the results showed diets containing Nano-calcium carbonate at levels 25-50 mg kg-1 in CN25 and CN50 groups could improve growth performance and metabolic activity of oriental river prawn in the biofloc system.

Rearing of ornamental fishes allocated high levels of annual income from the aquaculture industry. Spirulina is a blue-green algae, spiral shape with a diameter of 12 microns and rich source of protein, vitamins, amino acids and essential fatty acids, minerals and antioxidant pigments. Using different levels of spirulina was evaluated on immune indicators, digestive enzymes and reproductive parameters (fecundity and sexual maturation) of dwarf gourami.  One hundred and forty five dwarf gourami with an average weight of 3.6±0.23g were randomly distributed in twenty 12-liter aquarium. Four diets were prepared consisting of spirulina at levels of 3%, 7% and 10% substituted by fish meal and with a control diet. Parameters related to body biochemical, reproductive, digestive enzymes and immune index were measured. Increasing spirulina up to 7% enhance the ovarian weight (p<0.05). Hatching percentage and fecundity working has shown a significant increase with spirulina increased (p<0.05). Lipase, amylase and protease has significantly increased with increasing spirulina (p<0.05). Lysozyme and serum bactericidal have significantly increased with the increase of spirulina (p<0.05). Based on results 3% of spirulina due to improved reproductive factors and 10% to enhance immune indices and digestive enzymes in dwarf gourami considered as the best levels of substitution with fishmeal.

In the present study, cryopreservation of common carp (Cyprinus carpio</em>) embryos was studied using a stepwise cooling protocol. Embryos at heartbeat stage were selected, placed in 15- ml plastic tubes and stored at -2 °C for 1, 7, 14, and 21 days in 2 different cryopreservation solutions: S1 (methanol + dimethyl sulfoxide + sucrose) and S2 (methanol + propylene glycol + sucrose). Embryo viability was assessed by survival rate, counting live larvae and number of failed eggs under a stereomicroscope.  The results showed that storage of common carp embryos was possible for up to 7 days at -2 °C, while the survival did not occur when storage period were 14 and 21 days. The combination of methanol with propylene glycol (S2) gave higher survival rate after 1 and 7 days stored at -2 °C. Further studies are needed in order to extend the storage time and to improve the survival rate for this species.

In a 30-day feeding trial, Roach (Rutilus rutilus) and Carass (Carassius auratus) extracts were added to juvenile of beluga (Huso huso) diets at different levels in order to evaluate their effects on growth and survival rate. In this trial that was carried out in aquaculture researcher center of Gorgan University, three different dietary levels of extracts (1:25, 1: 50 and 1:100) were examined into account. The trial was carried out in 250 liters PVC tanks which were filled with about 125 liters of water.20 juvenile beluga (with average weight of 5.1 ± 0.2 g) were stocked in tanks and were fed up 4 meals per day. Growth and survival factors were analyzed at the end of trial period. The results showed that the adding of extracts in diets led to more improvement of body weight increase, weight increase percentage, and specific growth rate (SGR), Daily Growth Rate (DGR), Daily Growth Index (DGI), Condition Factor (CF), price index (PI) and decrease of Food Conversion Ratio (FCR) than the witness treatment. The best values of improvement of growth index were achieved at dietary level 1:25 Roach and Carass extracts And by comparing these two extracts Together with calculate the price of each extract dietary level 1:25 Roach was seen as the best treatment in this study.

This study had 8 treatments and 3 replications: Treatment A: one time feeding per day with SFK, Treatment B: two times feeding per day with SFK, Treatment C: three times feeding per day with SFK, Treatment D: four times feeding per day with SFK, Treatment E: one time feeding per day with mixture of SFK and fish powder (25% weight SFK), Treatment F: two times feeding per day with mixture of SFK and fish powder (25% weight SFK), Treatment G: three times feeding per day with mixture of SFK and fish powder (25% weight SFK), Treatment H: four times feeding per day with mixture of SFK and fish powder (25% weight SFK). Each of treatments in this examination were fed regularly at 8,11,14,17 hours. It’s necessary to notice that rate of feeding was based on 15 percent of weight of larval body fishes on a day. Results indicated that there was significant difference between weight and length gain (p<0/05). Fish larvae with one time feeding per day with SFK diet had the higher weight and length and fish larvale that fed with mixture of SFK and fish powder (25% weight SFK) had the most length and weight when they had feeding four times per day.

A 60-day feeding trial was conducted to examine the effect of dietary Ergosan on growth performance, survival and blood cells changes in beluga, Huso huso juvenile. Ergosan as algal product containing 1% alginic acid supplemented at 0, 2, 4 and 6 g/kg diet (diets A, B, C and D, respectively). Each diet was fed to triplicate groups of Beluga with the initial body weight of 41.7±1.8 g at 10 days intervals (1-10th, 20-30th and 40-50th with non-supplemented diets and 10-20th, 30-40th and 50-60th with supplemented diets). Control group fed with non-supplemented diet during the experiment. Fish fed with respective diets based on 5% body weight. Water temperature was 24.3±2.3 °C. Photoperiod was adjusted at 13 Light /11 dark. Growth indices in the fish fed with supplemented diets were significantly higher than the control group (P<0.05). Feed conversion ratio (FCR) in the fish fed diets B, C and D were significantly better than the control group (P<0.05), while PER was not different among groups. Survival was not different among all the treatments (P>0.05). Also, use of Ergosan resulted in significance differences in lymphocyte percentage, while there were no statistically significant differences in hematocrit, monocyte and myelocyte percentages, hemoglobin concentration, number of erythrocytes, total leukocytes, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Neutrophils and eosinophils percentage in the control group was higher than the fish fed with supplemented diet (P<0.05). These results indicated that dietary Ergosan affect some growth and haematological parameters in great sturgeon, Huso huso juvenile.