Aquatic Animals

This study was performed to evaluate the effects of different dietary levels of glucosamine on growth performance, serum biochemical and immune indices of Siberian sturgeon. Fish (9.3 ± 0.4 g initial weight) in 12 fiberglass tanks with a density of 15 fish/tank were randomly distributed and fed with different levels of glucosamine including: 0 (control), 250, 750 and 1500 mg per kg of diet (C0, T250, T750 and T1500, respectively) for 56 days. Based on the results, the highest final weight (63.1 ± 1.6 g), weight gain (54.14 ± 1.82 g), body weight increase (558.28 ± 23.23%), and specific growth rate (3.36 ± 0.08%/day) were observed in T1500 compared to the other treatments (p < 0.05). The results of this study showed that there are no significant differences in survival rate and blood glucose levels among the experimental treatments (p>0.05). The results of the serum immune indices exhibited that the highest levels of IgM (38.1 ± 0.5 mg/dL), C3 (5.20 ± 0.17 mg/dL) and C4 (20.72 ± 1.0 mg/dL) were observed in T1500 compared to other experimental treatments (p < 0.05). On the other hand, by increasing glucosamine concentration, the activity of hepatic enzymes including aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase was decreased and the lowest levels were observed in T1500 (p < 0.05). In conclusion, glucosamine, especially at the level of 1500 mg/kg of diet, displayed positive effects on the growth and immune indices of juvenile Siberian sturgeon.

This study was conducted to evaluate the effect of different levels of canola oil on growth performance and survival of Caspian salmon fry (Salmo trutta caspius) during replacement with canola oil over a period of 60 days. 180 fish fries (4.25 ± 0.68 g) with a density of 15 were distributed and introduced to 300 liter fiberglass tubs. For this purpose, 4 treatments with 3 duplication, diets including 100% fish oil, 100% canola oil, 50% fish oil and 50% canola oil, 70% fish oil and 30% canola oil (with the same protein and fat levels of 43 and 14%, respectively) were applied. The results showed that the highest weight (26.46 g), final length (13.46 cm) and specific growth rate (2.97%) were belonging to the treatment containing 50% fish oil and 50% canola oil which showed a significant difference with other treatments (p≥0.05). Moreover, the lowest value of feed conversion ratio (1.41) and the highest amount of status factor (0.09 ± 1.08) were also related to treatment 3, but these differences were not statistically significant (p≥0.05). The highest protein efficiency coefficient of 2.37 was related to the treatment containing a mixture of 70% fish oil and 30% canola oil, which showed a significant difference with other treatments (p≤0.05). The survival rate among all treatments was 100% (no losses). Based on the results, it can be concluded that the replacement of part of fish oil with canola oil (50% fish oil with 50% canola oil) in the diet of Caspian salmon not only has no negative impact on growth factors and survival of Caspian salmon, but also it will improve these factors and can decrease costs by reducing the length of the culture period.

In this study, in a completely randomized experimental design, the effects of different levels of duck weed (Lemna minor L.) meal in Caspian kutum diet on growth indices, carcass composition were investigated in an 8- week period. Different replacement levels of 0, 5, 10 and 15% were consisted the treatments in triplicates. Fingerlings with the mean initial weight of 2.02 ± 0.08 g were distributed in the experimental tanks. The results indicated that addition of duck weed powder in kutum diet more than 5% up to 15 caused a significant decrease (p < 0.05) in final body weight, specific growth rate and feed conversion ratio, conversely condition factor (CF) had not significant differences (p>0.05). It was concluded that with increasing the duck weed levels in diet, lipid, protein and ash contents did not show any significant differences in fish carcasses compared to control (p>0.05), however moisture increased with increasing the rates of duck weed in the diet. Getting the same results of growth indices in treatment containing 5% duckweed and control (p>0.05), confirmed that duck weed can be used at the level of 5% in the kutum diet.

This study carried out to increase production efficiency Persian sturgeon fingerling. For this experiment, in four treatments, 600 Acipenser persicus fingerling (10.76 ± 0.74 g and 14.49 ± 0.7 cm) were introduced into 12 fiberglass tanks with 300 liters water. The fingerlings were reared for 60 days. The diets with 150, 300 and 450 mg of 4 bacterial strains Lactococcus lactis, Pediococcus pentosaceus, Weissella cibaria and Enterococcus faecalis (powder per 1-kg of pelleted diets to make certain concentrations 1.5 × 109 (T2), 3 × 109 (T3) and 4.5 × 109 CFU/g (T4). The diet of the control group (T1) was also free of probiotic bacteria. The results showed that there was no significant difference in growth indices in different treatments (p>0.05), but the maximum and minimum mean final weight were observed in juveniles of T2 and T1, respectively. The results of liver enzymatic indices and LDH, IgM and lysozyme activity and the number of colonial intestine bacterial flora showed that the minimum and maximum values of these indices were observed with significant differences in T2 and T1, respectively (p < 0.05). The maximum and minimum number of intestinal lactic acid (probiotic) bacteria also occurred in T2 and T4 with a significant difference respectively (p < 0.05). In spite of the fact that a diet containing probiotics could not have a significant effect on growth indices in Persian sturgeon fingerling in the weight range of 10-60g, but the diet of containing probiotics with 1.5×109 concentration (T2), significantly improved the safety, enzymatic and bacterial flora of the intestine.

In this study, the nutritional effects of sodium citrate (SC) on some growth indices, antioxidant status and Lactobacillus bacteria population of yellowfin seabream (Acanthopagrus latus) juvenile (initial weight of 6.5 ± 0.2 g) were studied for 8 weeks. Three isonitrogenous and isolipidic experimental diets that fish meal was replaced with plant protein, supplemented with 0 g sodium citrate /kg diet (control), SC5 (5 g sodium citrate /kg diet) or SC10 (10 g sodium citrate /kg diet) sodium citrate. A total of three experimental diets were fed to three groups of yellowfin seabream. At the end of the nutritional experiment, the results exhibited that the mean final weight and weight gain indices in the fish fed with the sodium citrate were significantly higher than the control group (p<0.05). Survival rate was not significantly different between the treatments (p>0.05). The intestinal Lactobacillus population was significantly higher in the groups fed with the diets containing sodium citrate (p<0.05) than in control. Catalase and superoxidase superoxidase did not exhibit significant differences between experimental treatments (p>0.05). However, glutathione peroxidase activity was significantly higher in the treatments (p<0.05) than in control. Index of lipid peroxidation, malondialdehyde in SC5 and SC10 significantly decreased compared to the control group (p<0.05). These results indicated that dietary supplementation of sodium citrate at a level of 5 g sodium citrate per kg diet improved growth performance, antioxidant status and beneficial intestinal microbiota of the yellowfin seabream juvenile.

In order to determine the optimum feeding rate in rearing of stellate sturgeon, Acipenser stellatus, based on feed consumption, an experiment was conducted in three groups of low, medium and high weights of 11.71 ± 0.68, 41.2 ± 1.87 and 421.76 ± 15.88 g, respectively, in a completely randomized design in concrete tanks. The fish were fed based on appetite for seven months with 2 to 6 times daily feeding frequencies. The amounts of consumed feed and daily temperature were recorded. During the experiment, the temperature range was 13.5 ± 5.5 °C. At the end of the experiment, nutrition and growth parameters were measured. The results exhibited that the body weight gain, daily growth rate, specific growth rate and feed conversion ratio of fish in the low-weight group were significantly different from the other two groups (p<0.05). The maximum growth rate and lowest food conversion ratio were also observed in low-weight group. Furthermore, according to results, the average feed consumption rates in fish with 11-183 g and 41-173 g in weights were 1%, while 0.88% in those with 421 to 553 g in weight. No mortality was observed during the experiment in the studied groups. Moreover, according to the amount of feed consumed, a table was designed to determine the appropriate feeding rate in stellate sturgeon at different weights and temperatures, which can be a guideline for rearing of this species.

This study evaluates the effects of different levels of acidifier: Sodium diformate and citric acid on body composition, serum enzymes and the alimentary canal tissue in rainbow trout (Oncorhynchus mykiss). For this purpose, 630 fingerling fish(mean weight: 16.55 ± 0.72 g), were randomly distributed in twenty one 200-L fiberglass tanks (30 fish per tank). This study was performed 60 days with seven experimental treatments: control (only fed with commercial diet: FFT2),  three levels of sodium diformate added to diet: 0.2% (treatment A), 0.4% (treatment B), 0.6% (treatment C) and also three levels of sodium diformate in combination with citric acid with an equal rates: 0.1% (treatment D), 0.2% (treatment E) and 0.3% (treatment F). The fish were fed 2 %  based of body weight three times daily at 8:00, 12:00 and 16:00 for two months. The results indicated that different levels of sodium diformate and citric acid supplements used had no significant effect on the activity of serum enzymes of rainbow trout in comparison with the control treatment (p>0.05); while it had significant effects on the protein, ash and moisture of the body composition among the experimental treatments (p<0.05). The maximum height and width of microvilli, the number of goblet cells, the thickness of serous membrane, parin and submucosal layer of intestine along with the thickness of muscle layer were observed in treatment D, which exhibited significant differences with other treatments (p<0.05) and the minimum rate of the mentioned factors was recorded in the control treatment. Adding 1% sodium diformate and 1% citric acid to diet of rainbow trout can be useful because of the improving body composition indices, including an increase in protein and ash, as well as improving intestine histological indices.

The aim of this study was to investigate the effect of probiotics isolated from the intestine of Beluga (Huso huso) fingerlings on growth factors, activity of digestive enzymes and carcass composition of common carp (Cyprinus carpio, Linnaeus 1758) larvae. Three hundred and sixty larvae with an average weight of approximately 200 mg after one-week adaptation to the new conditions, were fed with supplemented diets with blend of Bacillus subtilis, B. licheniformis and Saccharomyces cerevisiae in concentrations of 1.5 × 106 (T1), 3 × 106 (T2) and 4.5 × 106 (T3) CFU/100 g diet, respectively for 45 days. In control group, larvae were fed with diet without any supplementation. The experiment was carried out in a completely random design. At the end of the experiment, the results revealed that the highest final weight (35 ± 0.12 ­mg) and specific growth rate (0.94 ± 0.66%/day) were measured in T3. The highest feed conversion efficiency (46.52 ± 19.02%), protein efficiency ratio (0.37 ± 0.41), lipid efficiency ratio (1.22 ± 1.34), retained protein (0.0018 mg/day) and net protein utilization (0.0058%) were found in T3, while the lowest feed conversion ratio (2.34 ± 0.61) was obtained in T3. All of the above factors had significantly difference with control group (p < 0.05). The maximum level of carcass crude protein (72.33 ± 0.68%) and crude lipid (13.43 ± 0.32%) were measured in T3. The  dry mater, crude energy and carcass ash levels did not exhibit significant differences in all the treatments compared to the control group (p>0.05). Amylase and lipase levels in the body extracts raised in the experimental treatments in comparison with the control group. However, only the amylase level displayed significant difference in comparison with control (p < 0.05). The experiment indicated that the blend of Bacillus and yeast at different concentrations displayed different effects on carcass analyses and feeding indices in this fish and the best results were obtained in T3 (4.5 × 106 CFU/100g diet).

Algae play an important role as primary feed in aquatic ecosystems and as food for zoo­planktons which are also important for the aquatic animals  husbandry in larval stages. Thus, their production  at the industrial scale is important. The marine microalgae Chlorella sp. was cultured under small-scale, batch culture condition, to evaluate the differences in growth rates (biomass production): using commercial agriculture fertilizers and analytical grade of inorganic salts for 20 days. Five different culture media were formulated as treatments including different concentration (%) of Cooper hydroponic culture media (T100%, T75%, T50% and T25%) and a control group, i.e.  F/2 medium (T0) which is commonly used for microalgae cultivation in commercial aquaculture without Cooper media. Chlorella sp. exhibited better results in T25% during different experimental time interval. Results also revealed that T25% is highly cost-effective as well, since it was almost 94% (sixteen times) cheaper than F/2 medium. The results suggest that commercial agricultural fertilizers could be added to the marine microalgae culture medium for providing the analytical grade nutrients with no significant side effect on the medium.

In the present study, the effects of dietary supplemented feed with a mixture of probiotic Bacillus sp. (1 × 108 CFU/100 g) were investigated on the growth performance and serum biochemical indices of Oncorhynchus mykiss larvae (0.23 ± 0.08 g) in different stocking densities. The experiment was conducted to a completely randomized design with four treatments and a control group with three replicates. The treatments based on the levels of stocking densities were 30, 45, 60 and 75 larvae (T30, T45, T60 and T75) in 10-L tanks. The stocking density of control group was 30 fish per 10-L tank (C10). The feeding period was 45 days. The highest final weight (3.06 ± 1.16 g) and the lowest FCR (1.01 ± 0.39) were observed in T60 (p<0.05). The SGR was significantly reduced in all experimental treatments compared to the control group (p<0.05). The highest total protein (9.70 ± 2.10 mg dL-1) and cortisol (84.50 ± 2.50 mg dL-1), and the lowest albumin (9.85 ± 1.05 mg dL-1) was measured in T30 (p<0.05). The highest glucose level (139.50 ± 4.50 mg dL-1) was measured in T60 (p<0.05). Adding probiotics to the diet of rainbow troutlarvae led to significantly reduced AST as well as increased ALT and ALP activities in the experimental treatments compared to control group (p<0.05). In conclusion, the results of this study showed that Bacilliprobiotics are capable of enhancing growth rate and also serum biochemical indices in rainbow troutlarvae. These findings may support the potential application of this probiotic as a practical supplementation in the diet of fish.

Jewel fish (Hemichromis bimaculatus)is a well-known and market-freindly ornamental fish in Iran. This work aimed to investigate the effects of caraway(Carum carevi)as a plant extract on growth, blood and immune indices in jewel fish in an 8-week period. So, 120 fish (5 g in weight) were distributed in 12 aquariums. A control group and 3 treatments were considered as follows: control group fed diet with no supplementation, treatment 1 (0.5%), treatment 2 (1%) and treatment 3 (1.5% caraway) in 3 replicates. Immunological and biochemical indices as well as growth performance were measured during the experiment. Among the growth indices, there was the best performance of SGR, PBWI, CF and FCR in treatment 2, exhibiting significant differences (p<0.05) with other groups. In additoin, treatment 2 displayed better results in terms of hemological indices. So that, the highest number of red blood cells, hemoglobin, hematocrit, MCHC, IgM, total protein, lysozyme, total immunoglobulin and HDL cholesterol were observed in treatment 2, exhibiting significant differences (p<0.05) with other groups. Therefore, it was found that adding 1% caraway to the diet can elevate the efficiency of immune system and also enhance the growth and nutritional indices in jewel fish.

This study was carried out to evaluate the effects of alcoholic and nanoencapsulated nettle (Urtica dioica) extracts on growth performance and hematological indices of rainbow trout (Oncorhynchus mykiss). A total of 225 rainbow trout with an average initial weight of 23 ± 0.16 g (mean ± standard deviation) were fed with five diets supplemented with 0% (control group), 1% alcoholic extract (A1), 2% alcoholic extract (A2), 1% nanoparticle extract (N1) and 2% nanoparticle extract (N2) for 8 weeks. The treatments A2 and N2 showed significantly higher final weight and specific growth rate compared to the control as well as  A1 and N1. The experimental diets exhibited significant effects on some hematological indices, such that the highest levels of white blood cells, lymphocytes, total protein, albumin and also lysozyme activity were observed in A2 and N2. These results suggested that supplementing diet with the alcoholic and nanoencapsulated nettle extracts enhance immunity, and promote fish growth.

The aim of the present study was to investigate the effect of different levels of inorganic supplements in hydroponic system with the water recycle system on some parameters related to the Nile tilapia health status. So, 180 fish weighing 30 ± 3.8 g was divided into 9 experimental units (3 for each treatment). The treatments included diets supplemented with 25% (T2) and 75% (T3) inorganic minerals in hydroponic system. The control group (T1) fed diet with no supplementation. Following 70 days, blood samples were collected from caudal vein of 5 fish. Results indicated significant alterations in hematological and immunological indices in treatments compared to control (p<0.05). Generally, the intestine epithelium development in addition to the enhanced hematological and immune indices indicates the better health status in Nile tilapia following dietary manipulation by inorganic supplementation.

In this study, the effects of lactoferrin (Lf)and spirulina powder (SP) alone or in combination on reproductive performance of female zebrafish Danio rerio were investigated. The fish with average initial weight of 0.27 g were fed with the basal diet (control, C) or diet enriched with Spirulina powder (SP 100 g/kg, TSP100) or lactoferrin (Lf 400 mg/kg, TLF400) or their combination (100 g/kg spirulina and 400 mg/kg lactoferrin, TSP100 + LF400) for 3 weeks. At the end of the experiment, some reproductive indices were determined including fecundity, egg diameter, hatching and fertilization rates, individual larval length and weight. The highest spawning rate was observed in TLF400 and TSP100 + LF400. Some reproductive indices such as fertilization and hatching rates were enhanced in TSP100 + LF400 (p<0.05). Egg diameters, larval survival and weight were also enhanced in TSP100 + LF400 (p<0.05). In case of the brood fish, which failed to spawn, significant enhancement in gonadosomatic index and relative fecundity were observed only in TLF400, while absolute fecundity, oocyte diameter and weight were significantly enhanced in TSP100 + LF400 (p<0.05). Raised reproductive performance in fish fed with lactoferrin and spirulina in this study, indicated their synergism effects on zebrafish diet.

The present study was conducted to examine the effect of dietary lysine and methionine amino acids on growth, blood parameters, liver enzymes and immune responses of beluga, Huso huso. Four experimental soy protein-based treatments including D0 (without lysine or methionine), D1 (lysine), D2 (methionine) and D3 (lysine + methionine) were formulated in triplicate groups. A total number of 240 juvenile beluga with average weight of 144.6 ± 4.64 g were fed with the experimental diets in the same rearing conditions for 12 weeks. L-lysine and DL-methionine were added to the diets containing 344 g/kg soybean meal at 22.02 and 12.94 g/kg dry diets, respectively. Growh indices in D3 (lysine + methionine) were significantly (p<0.05) higher than those in other treatments. The lowest content of HSI belonged to D0 (control) which exhibited significant difference (p<0.05) compated to the other treatments. The values of hematocrit, hemoglobin, glucose, total protein, liver enzymes and number of red blood cells in in D3 revealed significant enhancement compared to D0 (p<0.05). There was an increased immune parameter including total Ig and lysozyme in treatments with supplemented amino acids (D1, D2 and D3) compared to D0 (control) with significant difference in case of D3 (p<0.05). In conclusion, beluga juveniles effectively utilize the supplemented lysine at 22.02 g/kgand methionine at 12.94 g/kgin the dry diets containing 344 g/kg soybean meal to enhance growth performance, haematological and immune parameters.

The present study was conducted to evaluate the effect of probiotic bacteria Pediocucus acidilactici encapsulated with alginate and resistant starch (Hi maize) coated by chitosan, on growth indices, intestinal flora and carcass composition of rainbow trout (Oncorhynchus mykiss). Rainbow trout fingerling with an average weight of 18.41 ± 0.32 g were fed with diets including: encapsulated probiotic, free probiotic, diet containing capsules free of bacteria (positive control) and control diet containing no probiotics for 60 days. The results exhibited that there were no significant differences in growth rate, weight gain, specific growth rate and feed conversion ratio in different groups. The highest number of lactic acid bacteria was found in the fish received the encapsulated bacteria while the lowest was in the control group (p<0.05). Maximum carcass protein and fat contents were observed in encapsulated bacteria treatment and maximum carcass ash was in control group (p<0.05). Totally, the results suggest that encapsulated P. acidilactici improves the growth performance, body composition and bacterial flora of rainbow trout.