تغذیه

The type of food and the way of feeding is one of the most important challenges in the culture and reproduction of aquatic species. The marine ornamental fish business generates more than $1.5 billion annually and is still growing. However, only 35 species of fish, a small fraction of the 1,800 species recorded in the trade, are thought to be produced commercially today. A limiting factor in marine ornamental fish production is the need for live food of suitable size as starter food due to the small mouth gap size of many commercial fish species. Therefore, the need for suitable live feed has created a bottleneck in the production of marine ornamental fish species, and it is necessary to enable the expansion of this industry.  In this review, the use of common live foods, including Artemia, rotifers, copepods, and ciliates, and the advantages and disadvantages of each for commercial marine ornamental fish culture are presented. Live foods are often larger than the mouth gap size of marine ornamental fish larvae at the start of exogenous feeding. Advances are reviewed with a focus on new and existing live foods for these valuable species. These advances enable aquaculture to meet the growing demand for marine ornamental fish instead of exploiting wild populations.

The type of food and the way of feeding is one of the most important challenges in the culture and reproduction of aquatic species. The marine ornamental fish business generates more than $1.5 billion annually and is still growing. However, only 35 species of fish, a small fraction of the 1,800 species recorded in the trade, are thought to be produced commercially today. A limiting factor in marine ornamental fish production is the need for live food of suitable size as starter food due to the small mouth gap size of many commercial fish species. Therefore, the need for suitable live feed has created a bottleneck in the production of marine ornamental fish species, and it is necessary to enable the expansion of this industry.  In this review, the use of common live foods, including Artemia, rotifers, copepods, and ciliates, and the advantages and disadvantages of each for commercial marine ornamental fish culture are presented. Live foods are often larger than the mouth gap size of marine ornamental fish larvae at the start of exogenous feeding. Advances are reviewed with a focus on new and existing live foods for these valuable species. These advances enable aquaculture to meet the growing demand for marine ornamental fish instead of exploiting wild populations.

Feed preparation is the main part of the current expenditure of intensive aquaculture production. Insects might be used as whole and alive or as dried larvae to feed ornamental aquatic animals. Insects are usually produced using food waste and locally available materials. Also, they can be used as sources of oil, protein and other valuable compounds including chitin in aquafeed. Industrially produced insects have characteristics such as a short life cycle, low feed conversion ratio, the possibility of breeding on a large scale and high density with low-value feed sources. The amino acids profile of insects is suitable for feeding aquatic animals; they also have sufficient protein contents. Among the insects, the black soldier fly, mealworm and house fly are common. However, the black soldier fly is the most suitable terrestrial insect species for feeding ornamental fish, because its growth period is shorter compared to other species, and it does not also transmit diseases due to the lack of nutrition when it matures.

An eight-week study was conducted to examine the effects of dietary butyric and propionic supplementation levels on growth and gut microflora in juveniles’ sobaity seabream (Sparidentex hasta). In this regard, a basal diet (44% crude protein and 15% lipid) was supplemented with various levels of butyric (BA) and propionic acids (PA) to design seven experimental feeds as follow: 1-control (diet without organic acid supplementation), 2- BA 0.5%, 3- BA 1%, 4- PA 0.5%, 5- PA 1%, 6- BA+PA 0.5% (0.25% BA+0.25% PA supplementation), 7- BA+PA 1% (0.5% BA+0.5% PA supplementation). Three hundred and fifteen fish with initial weight of 28.5±0.5 g were distributed among 21 polyethilene tanks (300 L). The fish were fed with the experimental diets three times a day up to visual satiation making sure that no feed remain at the bottom of the tanks. Water temperature and salinity were 31.3 °C and 46 g/L, respectively. The fish fed with 0.5 and 1% PA or 0.5% blends of BA and PA had higher growth rate than other groups. Also, the improvement of food conversion ratio was observed in the treatment fed with 0.5% PA and 1% BA treatments. Total bacterial count in the gut did not affect by the experimental feeds but lactic acid bacteria count increased with supplementing acidifiers in diet. Based on the findings of this study, 0.5% PA or blends of PA and BA at 0.5% level are recommended for improving growth and gut health condition in juveniles’ sobaity seabream.

The present research conducted within 8 weeks, aimed at examining the impacts of white worm (Enchytaerus albidus) on the growth function of Goldfish fry (Carassius auratus). Therefore, the effects of mixed experimental diet A (30% white worm/ 70% dry feed) and the control diet B (100% dry feed) on Goldfish fries (150±2.21mg) were determined in two treatments and three replicates. At the end of feeding phase, weight gain percentage (%), daily growth (%), daily weight gain (mg), FCR, protein efficiency (g) and SGR (%) were calculated in both groups. The results revealed that all growth related indices in the fries fed with mixed diets stood higher than those of in the control .(P≤0.05). The study also showed that the inclusion of white worm (Enchytaerus albidus) in the diet of Goldfish fries improved their weight gain.

The present study was conducted in order to review the biological characteristics and breeding and maintenance methods of common platy (Xiphophorus maculatus) as one of the popular aquarium species in the world. The literature review showed that this species is native to subtropical and tropical regions including Mexico, Guatemala, Belize and Honduras. In terms of diet, common platy is omnivorous, and in terms of reproduction, if the water temperature is optimal, it leads to almost continuous reproduction in this species. X. maculatus is known as a peaceful fish, therefore, it is considered a very suitable option for keeping in social aquariums. In general, in terms of the physico-chemical properties of the habitat, platy fish prefer water with a high degree of hardness, which is similar to their natural habitat. The researchers stated that keeping the pH of the water in the range of 6.8 to 8.5 is very suitable for the life of these fish. According to the reports, the lifespan of common platy is three to five years, if it is properly cared for. Fin rot, Ich and velvet are among the most common diseases of platy fish in the aquarium environment. The overall findings showed that common platy (X. maculatus) due to having a series of special features such as small size, omnivorous diet, no need for a special bed and environment for spawning, as well as its high potential in tolerating a wide range of environmental conditions can be considered as an ideal and suitable option for breeding in home aquariums.

The purpose of this research is to investigate the relative importance of Avicennia marina organic matter in the feeding of Ilisha melastoma fish in the Mangrove Biosphere Reserve; It was stable isotope approach. Three primary food sources including mangrove tree leaves, microphytobenthos and suspended organic particles were analyzed isotopically. The samples of primary food sources and fish are converted into pure and simple gases such as CO, CO2 and N2 after minimizing the size and turning into powder. Then the identified isotope ratios are compared with a measured standard and the exact amount of isotope formed in the sample is obtained. In this research, sampling was done seasonally in August in the summer season and February in the winter season of 2019 in the mangrove ecosystems of Bandar Khmer, Hormozgan province.In the summer season, the average stable carbon isotope of primary food sources fluctuated from -28.07 units per thousand for mangrove leaves to -13.58 units per thousand for microphytobenthos.This average in the winter season was obtained from -28.05 units per thousand for mangrove leaves to -13.54 units per thousand for microphytobenthos.The average stable nitrogen isotope of primary food sources in the summer season fluctuated from 1.44 units per thousand for microphytobenthos to 10.72 units per thousand for suspended organic particles.The results of this research showed that in the summer season, suspended organic particles with 63% and in the winter season, microphytobenthos with 45% play the most important role in providing the food needed by the small shemsk fish.

In this study, the effect of different dietary levels of selenium on the growth of survival and muscle chemical composition of rainbow trout (Oncorhynchus mykiss) with an average weight of  80±0.57 g was investigated for 60 days. 320 fish were distributed randomly in 12 fiber tanks of 1500 L. Selenium was added at four levels, no selenium (control), 0.5 (treatment1), 1.5 (treatment2), and 3 (treatment3) mg/kilogram and the fish were fed for 6 weeks. The results showed that the specific growth rate, percentage of body weight gain, average daily growth, and food conversion ratio in the treatment fed with a diet containing 3 mg/kg selenium were significantly different from the control (p<0.05). There was no significant difference in the survival index between the investigated treatments and the control group (p>0.05). The effect of adding selenium on the chemical composition showed a significant difference in the level of carcass protein (p<0.05). The highest value related to treatment 4 (18.20±0.57 %) and the lowest value related to control group (16.47±0.16 %). In the treatments fed with selenium, a decrease in rainbowtrout fat was seen, which was significantly different from the control group (p<0.05). The moisture and ash levels in the control group were not significantly different from other treatments (p>0.05). The highest effect of selenium on growth was related to treatment 4 (3 mg/kg of selenium), but there was a significant difference with treatment 3 (1.5 mg/kg selenium) did not have (p>0.05). Overall, the results of this research showed the positive effect of adding 3 mg/kg selenium to the diet on the growth indices and improving the chemical composition of the rainbow trout.

The aim of this study was to evaluate the diet of the green tiger prawn, Penaeus semisulcatus for 12 months from January to December 2018 in the coastal waters of Hormozgan province. During this period, the intestinal contents of 673 of the two morphotypes of green tiger prawn including banding (417) and non-banding (256) were examined by the volumetric method. The results showed that the gut diet composition of both includes diatoms, dinoflagellates, crustaceans, mollusks, foraminifera, worms, and digestive material. There was no significant difference in the diet of the two types and males and females of green tiger prawns. Also, the study of the FP index showed that green tiger prawns were voracious creatures and their feed preference in female and male bonding was crustaceans 56% and 46% and 27% and 30% in diatoms, respectively, and in non-bonding types as well 65% and 57% in crustaceans and were 17% and 20% in diatoms respectively. Also, feed preferences in the next priorities for different sexes of both morphotypes included foraminifera, worms, unknown digestive substances, mollusks, and dinoflagellates with different percentages, respectively. There was a significant difference in the type of diet in different size classes so after crustaceans, diatoms were identified as the next preferred food in younger prawn diatoms and in older shrimp. The study of nutrition in different seasons of the year showed that crustaceans had the highest frequency and food preference in both morphotypes in all seasons and diatoms in summer, although the results related to the type and preference of food seasonally and based on the sex of shrimp showed no significant difference (P> 0.05).

This investigation was carried out to determine the effect of feeding strategies on growth performance, biochemical parameters, and hematological indices in male rainbow trout (Oncorhynchus mykiss) broodstocks. For this purpose, 45 broodstocks with 475.55 ± 54.24 g (mean ± S.D) were divided into three treatments and fed at satiation, restricted feeding (50% of satiation limit), and starvation levels in concrete ponds. The flow rate was 1 liter per second for each replicate and the broodstocks were fed for 8 weeks with extruded feed. According to the results, the final weight of the starvation treatment had a significant decrease compared to the restricted and satiated treatments (p<0.05). Moreover, the weight gain, body weight increase and specific growth rate showed significant differences among the treatments (p<0.05), but the condition factor was not significantly different (p>0.05). A significant difference was observed in feed conversion ratio between the restricted and satiated groups (p<0.05). Hematological indices did not show any significant difference between the treatments (p>0.05). In the blood biochemical parameters, plasma glucose level in the starvation treatment showed a significant difference with the restricted feeding and satiation treatments (p<0.05). In addition, blood globulin level of the starved fish was significantly different with the starvation treatment (p<0.05). In general, the present study showed that unpredictable stresses during the breeding season and the consequent reduction or interruption of feeding regimes could adversely affect the performance of male breeders, including growth indices and some physiological parameters.

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.

One of the limitations of aquaculture is the supply of fish meal needed for the aquaculture industry, but the use of plant items instead of fish meal contain anti-nutrients such as non-starch polysaccharides, which is one of the main limitations of using plant items in the diet of carnivorous fish. The present study investigated the in vivo and in vitro enzymes of alpha-amylase, cellulase, xylanase, and beta-glucanase on 210 rainbow trout (weight average 17.17 ± 3.85) in 7 treatments (three replications) including adding enzyme mixtures 24, 12, 6, 3 hours before production, the enzyme was added during production and after production for 60 days. First, the enzymatic composition for wheat flour and soybean meal was designed by in vitro test.The required enzyme levels of alpha-amylase, cellulase, xylanase, and beta-glucanase for wheat flour are 0.5, 0.1, 0.3 (g/kg), and 0.2, respectively, and for soybean meal are 0.5, 0.2, 0.5, and 0.1 (g/kg), respectively. . After producing the diets, feeding was done three times a day until satiety. At the end of the experiment, 3 fish were randomly sampled from each replicate to measure the total bacterial flora, intestinal lactobacilli, and measure blood parameters. According to the results, enzymes were not effective on white blood cells, red blood cells, hematocrit, and complement index, but increased serum cholesterol and triglyceride levels in the treatment of adding enzyme mixture 6 hours before production. Glucose levels were higher in the treatments of adding enzyme mixture 3 and 6 hours before production. The number of intestinal lactobacilli was higher in treatment of adding enzyme mixture 6 hours before production. And serum lysozyme in the treatment of adding the enzyme mixture 6 hours before production is higher than other treatments.In general, the results of this study show that the use of enzymes in the diet of rainbow trout changes the bacterial population of the intestine and the time of adding the enzyme to food items changes the efficiency of the use of enzymes.

Today, due to the confirmation of the existence of polyphenolic compounds with antioxidant properties in pomegranate peel, the study of its application potential in food health and fishery products has been the focus of researchers. In the present study, the effects of oral administration of ethanolic extract of pomegranate peel (Punica granatum L.) (Dose: 600 mg/kg) on functional changes of antioxidant system and biochemical parameters of blood serum of common carp (Cyprinus carpio) during a 45-day exposure against stocking density stress was monitored. In this regard, fish were randomly divided into 6 groups (3 treatment groups and 3 control groups with different levels of stocking density (3, 5, and 10 kg / m3) and three replications. At the end of the exposure period, fish bloodletting and serum preparation were performed. The results of this study did not show a significant increase in biochemical parameters (phosphorus, chlorine, magnesium, calcium, and triglycerides) as well as the activity level of some enzymes and antioxidant compounds such as SOD and MDA in fish serum compared to the control group. However, for stress indicators such as glucose and cholesterol and antioxidant activity such as CAT and GSH, production level has been significant. According to the findings, oral administration of pomegranate peel extract dietary supplement is recommended for consumption in dense aquaculture centers of common carp fish.

This experiment evaluated the effect of soluble polysaccharides in Spirulina platensis microalgae on growth performance, body composition and immune response of rainbow trout (Oncorhynchus mykiss). In this regard, 180 rainbow trout (17.22 ± 0.5g) were selected and distributed in five experimental treatments (with three replications). Treatments included different levels of polysaccharide in dosage of 0 (control), 500, 1000, 2000 and 3000 mg / kg of feed. According to the results, in growth factors (final weight, body weight gain, specific growth factor, protein efficiency, feed conversion ratio and condition factor), no significant difference was observed. The highest and the lowest amount of carcass proteins were observed in the diet containing 500 mg polysaccharide and control, which showed a significant difference. The amount of fatty acids of the muscle of the fish body did not show any significant difference among the treatments. The highest and lowest levels of lysozyme activity were observed in treatments of 2,000 mg polysaccharide and control and the highest and lowest levels of complement activity were observed in treatments containing 3000 mg polysaccharide and control respectively (P <0.05). In general, the use of polysaccharide extracted from micro-algae did not significantly improve rainbow trout growth, but a slight improvement in growth and body composition (protein) in 500 mg polysaccharide per kg of diet was observed. In terms of safety indicators, treatments of 2,000 and 3,000 mg of polysaccharides per kg of diet had a good performance and could be used whenever needed.

In this study, the possibility of using migratory locust as a source of protein in the diet of rainbow trout fry and its effect on growth performance, immunity and hematology of blood serum was investigated. 300 number of rainbow trout fingerling with an average weight (6.09 ± 0.22 gr) with diets of 0% (control), 15% (LM15), 30% (LM30) and 60% (LM60) of formulated locust meal. became Each diet was distributed in a completely random design in 3 replicates with 30 number of fish in each fiberglass tank with the same conditions. At the end of the experiment, the indicators of growth, immunity and blood serum hematology were calculated based on standard formulas and analyzed using Tukey's test. The results showed that the highest final weight was observed in the 30% treatment (616.20% ± 34.89%) and the difference between zero, 15% and 60% treatments was significant (p<0.05). In the 60% treatment, a significant increase in feed conversion ratio was observed compared to the control treatment (p < 0.05). In feeding fish with a diet containing locust meal, the values of glucose, albumin, globin and IgM did not show significant differences among different experimental treatments (p<0.05). However, the amount of total protein, triglyceride and blood cholesterol showed a significant difference in the experimental treatments compared to the control treatment (p < 0.05). Therefore, it can be concluded that the use of 30% of locust meal in the commercial diet of rainbow trout fingerling can improve the growth performance and have no negative effect on the desired level of blood and immune parameters..

Proper nutrition is one of the most important pillars of success in the aquaculture industry, which accounts for about 50% of costs and on the other hand ensures survival, proper growth and aquatic health. The aquaculture industry always has stressors such as high density, transportation, manipulation and changes in water quality that have an adverse effect on fish health and growth. In fish, stressors initiate hormonal cascades along the hypothalamic-pituitary-internal (HPI) and hypothalamic-sympathetic-chromaffin (HSC) axes to trigger several physiological reactions to regulate and maintain homeostasis and adversely affect various fish physiological processes such as Grows growth, reproduction and immunity. In fish farming, several ways are used to prevent the negative effects of stress and achieve maximum animal health without affecting production performance, and the use of new feeding strategies is an easy and practical way to improve the health of fish. Changes in the ratio of proteins, fats and carbohydrates in the diet, the use of vitamins, especially ascorbic acid, new substances in biotechnology such as probiotics, nucleotides and polysaccharides have been studied. Fatty acids, probiotics and minerals. Immunosuppressants are prescribed as food additives, which usually increase innate (non-specific) defense mechanisms and resistance to certain pathogens, and increase inhibition of stress-induced immune suppression. In this review, different physiological responses were assessed among fish species fed stress-reducing diets.

The aim of this study was to investigate the effect of adding lactic acid to the diet of rainbow trout on growth indices, activity of digestive enzymes and microbial flora of the fish gastrointestinal tract. For this purpose, 4 diets containing 0, 5, 10 and 20 g of lactic acid per kg of diet were made and each diet was offered to fish in three replications for 8 weeks. The results showed that there was no significant difference in growth and survival indices between different treatments (P> 0.05). The highest activity of gastric pepsin enzyme was observed at the level of 10 and 20 g of lactic acid in the diet (P <0.05). The highest alpha-amylase activity was observed at the level of 10 g of lactic acid in the diet (P <0.05). Lipase activity in the control treatment and 10 g of lactic acid in the diet was similar and significantly higher than the treatments of 5 and 20 g of lactic acid in the diet (P <0.05). Intestinal protease activity in treatments of 5 and 10 g of lactic acid in the diet was higher than the control treatment and the highest activity was related to 10 g of lactic acid (P <0.05). Treatment of 20 g of lactic acid in the diet had lower protease activity than the control treatment (P <0.05). The highest number of total intestinal bacteria was observed at the level of 5 and 10 g of lactic acid in the diet (P <0.05). The number of intestinal lactic acid bacteria in lactic acid treatments was significantly higher than the control treatment (P <0.05). The highest number of lactic acid bacteria was observed in the treatment of 10 g of lactic acid in the diet (P <0.05). According to the results, the addition of lactic acid to the rainbow trout diet has no effect on growth, although it does increase the activity of digestive enzymes. However, adding 10 g / kg of lactic acid leads to an increase in lactic acid bacteria in the gut of the fish.

Nowadays, sea foods are considered to provide more than 50% of the nutritional demands of ‎human communities. Therefore, with the development of the seafood market, the aquaculture ‎industry continues to grow day by day. Currently, some aquaculture food ingredients are made ‎from low price fishes (in the form of fish powder) and plants. But, the production of fish powder ‎cannot be increased due to disruption of the stability of aquatic ecosystems; Therefore, alternative ‎and environmentally friendly sources should be developed for aquaculture food ingredients. ‎Microalgae biomass suggests as a natural source instead of fish powder because the cellular ‎metabolites of these microorganisms contain a combination of essential amino acids, unsaturated ‎fatty acids, vitamins, and pigments. In addition to these unique properties and bioactive compounds ‎that are a major component of aquatic nutrition, microalgae can increase the survival of farmed ‎species, and improve the color and quality of fillets. Microalgae have the highest biomass productivity ‎among photosynthetic organisms, including forage crops, and therefore have high commercial ‎potential. Also, the production of microalgae does not require special arable land and freshwater ‎resources, which makes the feed based on microalgae contribute to environmental sustainability. ‎This article is a review of studies on the potential and application of microalgae in aquatic nutrition ‎to increase the productivity of aquaculture products.‎

In this study, the possibility of using locusts as a source of protein in the diet of rainbow trout and its effect on growth performance and blood biochemical parameters were investigated. 300 fish with average weight (5.08 ± 0.33g) with diets of 0% (control), 15% (SG15), 30% (SG30) and 60% (SG60) locust meal were formulated, with equal protein energy contents. Diet was distributed in a completely randomized design in three replications for eight weeks and twenty-five pieces of fish with the same conditions, in each tank. At the end of the experiment, growth, biochemical and safety indices were calculated based on standard formulas and the analysis was performed using Tukey test. The results showed that the highest final weight was observed in 30% treatment )89.34 ± 20.61%) and the difference between 0, 15 and 60% treatments was significant (p <0.05). In 60% treatment, a significant increase in feed conversion ratio was observed compared to the control treatment (p <0.05). In feeding fish with locust meal diet, glucose, cortisol, albumin, globin and IgM levels did not show significant differences between different experimental treatments (p <0.05). However, the amount of total protein, triglyceride and blood cholesterol showed a significant difference in experimental treatments compared to the control treatment (p <0.05). Therefore, it can be concluded that the use of 30% locust meal in the commercial diet of rainbow trout fingerling, in addition to adversely affecting blood and safety parameters, can improve growth performance.