فصلنامه تغذیه آبزیان
سال پنجم شماره 2 (پیاپی 10، پاییز و زمستان 1398)

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 zoo planktons 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.

Abstract The aim of this study was to investigate the prebiotic effect of mushroom on the immune indices of tilapia mucus exposed to chlorpyrifos on 120 juveniles tilapia with an average weight of 20 g. So, 4 treatments were considered as (1) control without prebiotics, (2) treatments containing 0.05%, (3) 0.1% and (4) 0.2% of dietary prebiotics. At the end of the feeding period, fish were exposed to chlorpyrifos toxin at a concentration of 0.05 ppm for 14 days and mucus sampling was taken from the fish skin. Experimental treatments exhibited significant effects on alkaline phosphatase, lysozyme, soluble protein, and mucus immunoglobulin (p<0.05). So that, the amounts of alkaline phosphatase, lysozyme and mucus soluble protein were significantly increased in treatments fed with prebiotic-supplemented diets by increasing in prebiotic concentration (40.40 IU/L, 36 Unit/mg Pro and 99.54 µg/100 µL, respectively). However, the amount of mucosal immunoglobulin decreased in these treatments (69 µg/100 µL). Overall, supplementing diets with prebiotic (mushroom powder), leads to enhanced immune system (elevating alkaline phosphatase, lysozyme, immunoglobulin, and soluble protein) when exposed pollutants and stressors.

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.