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Showing 13 results for mahmoudi
B. Bahmani , A. Zariffard , M. Khodadadi , N. Mahmoudi , A. Ojeefard ,
Volume 19, Issue 4 (1-2011)
Abstract
This research was carried out for 10 successive weeks (2 weeks for adaptation and 8 weeks for culture) in summer 2008 at Abzisytan Shrimp Hatchery Center in Bushehr province. The effects of dietary nucleotides at 5 levels including 0.0% (control), 0.15%, 0.25%, 0.35% and 0.5% on the growth performance and whole-body composition of Epinephelus coioides was investigated. Juvenile fish specimens with average weight of 10.70±0.29g were fed by experimental diets for 8 weeks. The trial was carried out in 300 liter fiberglass tanks. The highest protein content was observed in 0.15% diet nucleotide and the highest fat in 0.15% and 0.25% diet nucleotide which showed significant difference with the control group (P<0.05). The highest and lowest ash content was observed in 0.15% and 0.35% nucleotide treatment, respectively. The ash content showed significant difference between 0.15%, 0.25% and 0.35% treatments and control group (P<0.05). Also, the 0.35% treatment had the highest water content (P<0.05). We conclude that at the level of 0.15% dietary nucleotide, better results are achieved in terms of whole-body composition
B. Falahatkar , H. Abdi , N. Mahmoudi ,
Volume 21, Issue 1 (4-2012)
Abstract
Considering the effects of dietary nucleotides on growth and metabolism, this study was conducted to determine the effect of different levels of this nutrient on the sources of the body needed energy, and growth performance of common carp. Fish with average (±SD) weight of 7.5±0.2g were fed to five levels of dietary nucleotides containing 0, 0.1, 0.2, 0.3 and 0.4 percent for 8 weeks. Fish were fed 5 times daily according the satiation. After 56 days, the results showed that the level 0.2% nucleotide had the highest growth rate in terms of weight and length, but other parameters such as body weight, specific growth rate and feed conversion ratio, differences were not significantly changed. Biochemical analysis of serum parameters and proximate analysis showed that the physiological function of fish affected by different levels of nucleotides whereas in the energy supply sources, including glucose, triacyleglycerol, total protein and albumin there were no significant difference in cholesterol and lipid content of carcass. This study conveys a positive effect on the biosynthesis of dietary nucleotides on energy sources and growth functions, while the common carp has ability to synthesize this substance into the body, the level of 0.2% in the diet can affection *Corresponding author sufficient effect on growth and some biochemical indices.
E. Haghshenas, M. Gholamalifard, N. Mahmoudi,
Volume 26, Issue 1 (4-2017)
Abstract
Marine and coastal ecosystems have many benefits and different services for humans that marine aquaculture is one of the most important of these services. Southern coast of Caspian Sea particularly Mazandaran coast have great potential for development of marine aquaculture. Now, there are 9 fish farms with different production capacities in Mazandaran coast. In this study, the growth of specie of fish Rainbow trout (Oncorhynchus mykiss) was modeled using the marine aquaculture model based on daily temperature, rate of metabolism and mortality rate. Finally calculated the harvest weight and net present value (Net Present Value: NPV) for this this specie in each farm was calculated by considering two scenarios: 1) Development and 2) BAU (Business as Usual) that in each scenario equal to 2786 and 1121 tons with the NPV 11158 and 15788 million toman in total mazandaran coast during 1 years. So production of Rainbow trout is more economic. Results show that growth cycle fom the release (200 g) to harvest for Rainbow trout and is 2 cycle in 1 year. Also, duration of growth cycle decreases when temperature increases such that at 14, 16 and 18 degrees Celsius was142, 124 and 110 days, respectively. Since aquaculture farms on the Mazandaran coast had been grownd mostly Rainbow trout so this study is evaluated the production and NPV for this specie. Rainbow trout is a non-native specie in South Caspianso so is necessary that be studied effects and consequences of production the specie in this area.
M. Yasemi, A. Sarpanah, M. Mahmoudi Khoshdarehgi, M. Parsa,
Volume 26, Issue 2 (7-2017)
Abstract
In this study, in order to investigate the effect of Caraway (Carum carvi) on growth parameters and body approximate composition of Huso huso (Linnaeus; 1758) fingerlings, 3 diet containing 10%, 15% and 20% of Caraway with control diet that had not Caraway in its composition was utilized for feeding the Huso huso fingerlings. Fishes with initial mean weight of 10 g were fed with control diets in 7 weeks and growth parameters including total length, total weight, protein efficiency ratio, feed conversation rate and body approximate compositions were measured and analyzed. Results showed that the diet with 15% Caraway has the best effect on growth parameters of Huso huso fingerlings and lead to more gaining weight (146.60±1.85 g) than other diets. Moreover, between body approximate compositions, only the protein and moisture level were affected by diets containing Caraway. Maximum protein was observed in fingerlings fed with diets containing 10% and 20% Caraway. According to obtained results, using the diet with 15% Caraway recommend in order to enhance growth of Huso huso fingerlings.
S. Mahmoudi, M. Banaee, P. Shoukat, A. Noori, L. Mousavi Dehmoredi,
Volume 26, Issue 2 (7-2017)
Abstract
The purpose of this study was to evaluate histopathological changes in gills, spleen, liver, kidney and intestine of farmed rainbow trout in four different stations along with Barm Spring (Lordegan, Iran). In this study, at least 15 fish from each farm were captured and following autopsy, sampling was carried out from the gills, liver, spleen and intestine of fish. After tissue sectioning, samples were stained with hematoxylin and eosin. Tissues were studied with a 400X magnification. Gill lamella stick together, gill hyperplasia, exfoliation of gill epithelium, epithelial necrosis and hypertrophy and swelling of gill lamellae, hypertrophy and liver fat degeneration, glomerular and collecting duct of urine degeneration, increase in the lumen space, shrinking the glomerular as well as an increase in melanomacrophage centers (MMC), disorganization of ellipsoids in the spleen, necrosis of epithelial cells, exfoliation of the mucous layer of intestine were the major histopathological alterations observed in the fourth (less than 20% of the group) and the third (a few of fish) group. The results of this study showed that these alterations may be due to an increase in the chemicals in downstream water. Therefore, these histopathological changes could be used as an appropriate biomarker to water quality monitoring.
N. Pourang, F. Parafakndeh, H. Moazami, D. Agha Aligol , P. Ghavam Mostafavi , M. Mahmoudian,
Volume 27, Issue 1 (5-2018)
Abstract
In this research, the potential use of five hard parts (otolith, scale, eye lens, dorsal spine, vertebral bone) of Rutilus kutum for populations discrimination and biomonitoring as well as their usability as biological archive in the southern Caspian Sea was investigated. Two soft tissues (muscle and liver) were also analyzed for assessment of the possible risk of consumption and use as biomonitoring tool, respectively. A total of 60 specimens were collected using beach seine from three sampling sites (adjacent to the estuaries of the rivers Sefidrud, Tajan and Grorganrud, respectively) in the Southern Caspian Sea in May 2016. In total, the levels of 13 major and trace elements in the samples (the seven soft and hard tissues) was measured using PIXE (Proton Induced X-ray Emission) and µ-PIXE methods. Minor similarities among the tissues were observed in the case of eye lens (for P, S and Zn) and liver (for Cl, Fe and K). There were no significant relationships between the elements and biological characteristics (weight, total length and standard length). Based on the results, it seems that all the studied hard parts, except for eye lens, may offer alternatives for biomonitoring of Ca, Cl, Fe, K and S in the southern Caspian Sea. Considering Sr level in otolith, no significant differences could be found between the sampling sites 2 and 3. So it can be concluded that the specimens collected from the two sites are probably from the same population. Similar results were also obtained based on the results concerning K accumulation in scale. It can be concluded that scales may provide an alternative structure to otolith for stock discrimination of R. kutum in the southern Caspian Sea. Among the 10 elements that were detectable in the muscle using the PIXE method, only in the case of four of them (i.e. Zn, Cu, Fe and Mn) maximum allowable concentrations for human consumption have been defined, which in all the cases the mean concentrations in the present study were far below the recommended limits.
Z. Mahmoudikia, A. Imani, K. Sarvi Moghanlou, M. Razi,
Volume 28, Issue 1 (5-2019)
Abstract
The effect of stocking density and dietary aflatoxin B1 along with including rosemary and thyme powders on digestive enzymes activity of rainbow trout was evaluated. 600 fish with an average weight of 90±3 were randomly allotted into six experimental groups consisted of (1) stocking at 15 kg.m-3- feeding diet devoid of aflatoxin, (2) stocking at 45 kg.m-3-feeding diet devoid of aflatoxin, (3) stocking at 15 kg.m-3-feeding diet containing 50 ppb aflatoxin, (4) stocking at 45 kg.m-3-feeding diet containing 50 ppb aflatoxin, (5) stocking at 15 kg.m-3-feeding diet containing 4% rosemary and thyme powder and 50 ppb aflatoxin and (6) stocking at 45 kg.m-3-feeding diet containing 4% rosemary and thyme powder and 50 ppb aflatoxin. Activity of alkaline protease, lipase and amylase was only affected by fish stocking density to the extent that those fish were reared in higher density showed increased digestive enzymes activity (p<0.05). Interactive effect of two studied factors (stocking density and dietary supplementation of medicinal plants) significantly affected activity of amylase and alkaline protease. However, lipase was only affected by dietary supplementation of medicinal plants. The highest amylase and alkaline protease activity were recorded in those fish received diet devoid on medicinal plants and stocked at 45 kg.m-3 (p<0.05). Those fish received diet containing medicinal plant powder significantly had lower activity (p<0.05). Proximal intestine histological examinations revealed that those fish stocked at higher density and received aflatoxin contaminated diet had villi detachments. Nevertheless, dietary inclusion of herbal blend consisted of rosemary and thyme powder could retrieve such tissue abnormality. It seemed that intestine could resist tension from higher stocking density or dietary aflatoxin contamination; however, their combination was not endurable for fish. Meanwhile, further complementary researches such as assaying antioxidant enzymes activity are warranted to precisely elucidate the underlying mechanism behind such alterations.
Soheil Eagderi, Atta Mouludi-Saleh, Mohammad Mahmoudi, Fardin Hakimi,
Volume 30, Issue 5 (12-2021)
Abstract
This study was conducted in 2017 by sampling from 7 stations in the headwaters of the Taleghan River to study the habitat suitability of Brown trout, Salmo trutta. Sampling was carried out using an electrofishing device with three replications in each station. Eight environmental factors, including water temperature (°C), water depth (cm), river width (m), slope (degree), water velocity (m/s), average diameter of the dominant bedrock (cm), potamal width and elevations were measured. The values of suitability index of the studied factors in each station were determined and the arithmetic mean of the indices in all sampling stations was considered as the suitability index of that factor. The results showed that the most preferred temperature is in the range of 10-5-12°C, depth in 20-30cm, river width in of 2.5-3m, slope in 1.6-1.9, water velocity in 0.41-0.62m/s, elevation in 2250-300 m and average diameter of the dominant bedrock in 11-20cm, and the potamal width 1.8-3.6m were calculated. As a general conclusion, the Taleghan River had a moderate suitability for S. trutta.
Saltanat Najjar Lashgari, Mohammad Pourkazemi, Sajad Nazari, Abolfazl Sepahdari, Roghayeh Mahmoudi,
Volume 31, Issue 4 (11-2022)
Abstract
Considering the importance of evaluating genetic diversity and population structure in managing and selecting the most efficient breeders for reproduction, genetic diversity of rainbow trout (Oncorhynchus mykiss) pre-breeders in selected farms of West Azerbaijan province (farms 1, 2 and 3) was studied using seven pairs of microsatellite primers. For this purpose, 50 pre-breeders of each field were sampled and genomic DNA was extracted using ammonium acetate method. To observe the alleles and determine their size were used vertical electrophoresis of 6% polyacrylamide gel and silver nitrate staining. Relevant calculations were performed using Excel, INTAS GEL DOC and PopGene software. Based on the results, the highest number of real alleles (7.71) and the amount of observed heterozygosity (0.46±0.12) was observed in farm fish of No. 3 and the lowest number of real alleles (5.29±0.01) and the amount observed heterozygosity (0.34±0.08) was observed in farm fish No. 2. The highest genetic distance (0.07) and the lowest genetic similarity (0.93) were calculated between farm fish No. 3 & 1 and the lowest genetic distance (0.02) and the highest genetic similarity (0.98) were calculated between farm fish No. 2 & 1 were calculated. The highest amount of genetic differentiation (0.077) was obtained between farm fish No. 3 & 1 and the lowest amount (0.034) was obtained between farm fish No. 2 & 1. The results of molecular analysis of variance indicate the existence of significant genetic diversity differences between the fish of the studied farms (p<0.001). The results of FST test showed that the genetic differentiation between the breeding populations in this study is moderate and was evident the shift of breeders between different populations in the recent past or the use of a reference population and breeders with similar gene storage in propagation season among the studied farms. The findings of this study suggest that high mixing of populations with each other and factors such as selection and current policies of each farm may have led to a reduction in genetic diversity and differentiation between populations. The results of this study can be used to manage breeding stocks and breeding programs of this important commercial species.
Eisa Falahat Naserabad, Esmaeil Kazemi, Seyed Abdolhamid Hoseini, Mohamad Meisam Salahi Ardakani, Roghieh Mahmoudi,
Volume 32, Issue 3 (9-2023)
Abstract
In this research, the effect of selenium nanoparticles on the performance of antioxidant enzymes, including superoxide dismutar (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), and catalase (CAT) levels, and male reproductive egg ions of rainbow trout was investigated. The number of 144 fertile pieces of 4-year-old Iranian females was divided into four treatments in three replications. The treatments were fed with diet containing zero (control), 0.5, 1 and 2 mg of selenium nanoparticles per kg of diet for 60 days until egg maturation. Based on the results of the research, the values of SOD, CAT, and MDA have shown significant differences in the eggs from different treatments (p<0.05). The lowest level of SOD enzyme and the highest level of CAT enzyme were observed in the control treatment, which showed a significant difference with other treatments. There was no significant difference in the amount of GPx enzyme between different treatments (p>05). The amount of MDA enzyme showed a significant difference among the treatments, while the control group had the highest level of 363±16.8 mmol/ml and the fish fed with selenium nanoparticles at 2 mg/kg had the lowest level of 181±9.5 mmol/ml Comparing the average amounts of magnesium and calcium among different treatments showed a significant increase in the amounts of the mentioned ions in the treatment fed with selenium nanoparticles at the rate of 2 mg/kg of food compared to other treatments (p<0.05). In general, considering the decreasing role of antioxidant enzymes and its increasing role in the amounts of magnesium and calcium inorganic compounds in the eggs of mothers fed with more selenium nanoparticles, this essential micronutrient can be used as It should be considered as a suitable candidate for further research in order to improve the quality of spawning eggs of female rainbow trout by adding to the diet.
Mohammad Meysam Salahei Ardelani, Mahmood Hafezieh, Roghayeh Mahmoudi, Seyed Hossein Moradiyan, Hassan Nasrollazadeh Saravi,
Volume 33, Issue 1 (4-2024)
Abstract
In order to evaluate the quality of effluent pollutants from the rainbow trout breeding farms in the selected farms of Kohgiluyeh and Boyer Ahmad Province, water samples were taken from five individual farms during the years 2021-2022. The physical and chemical indicators of water including acidity, biological oxygen demand, dissolved oxygen, electrical conductivity, nitrite, nitrate, phosphate, total suspended solids, total dissolved solids, total hardness, alkalinity, iron, oxygen saturation were measured once in each season from the inlet and outlet water (each treatment with 3 replicates). Based on the results, the range of pH changes (5.93-7.29), biological oxygen demand (6.41-7.56 mg/l), ammonium (0-0.319 mg/l), nitrite (0-0.181 mg/l), nitrate (2.19-19.2 mg/l), phosphate (0. 1-0.18 mg/l), total alkalinity (132-238), dissolved oxygen (3.35-8.11 mg/l), electrical conductivity (311-899 microsiemens/cm), TDS (203.7-607.9), and total hardness (312-157.77 mg/l) were obtained. The results showed that the concentrations of ammonium, nitrite, nitrate, phosphate, EC, and total dissolved solids parameters in the effluent compared to the input from the different farms has increased due to the increase of metabolism, fish density, concentration of nutrients, drugs and disinfectants, intensity and speed of water and the oxygen concentration in the effluent of the farms has decreased due to more metabolic activities than the input from the rearing ponds. Also, the amount of biochemical oxygen demand (BOD) and environmental chemical oxygen demand (COD) were increased and the dissolved oxygen was consumed and its amount decreased due to the increase of organic substances, nitrate, and the provision of oxidation conditions.
Seyed Abdolhamid Hosseini, Alireza Ghaedi, Roghayeh Mahmoudi, Mansour Sharifiyan,
Volume 33, Issue 4 (10-2024)
Abstract
Introduction
Ensuring food and nutritional security is a top issue for global food-producing sectors among the projections of a 60% increase in food consumption by 2050 due to population growth. To address this challenge sustainably, the food and feed industry must conserve resources while feeding a growing population (Saiprasad et al., 2023a). This rapid expansion of aquaculture has led to increased demand for protein sources for feed production (Wang et al., 2023) and straining the supply of natural protein ingredients, such as fishmeal and plant protein sources. As a necessary way to reduce protein inclusion levels in aquaculture feed, lipids and carbohydrates are extensively used. Lipids can serve as an energy source with high energy density, and fish has good lipid absorption and utilization ability. Carbohydrate is a cheaper energy source than lipids and protein, which also serves as a swelling and stabilizer agent in fish feed (Kamalam et al., 2017). However, numerous studies have demonstrated that long-time ingestion of a high lipid/carbohydrate diet causes disturbance of lipid metabolism, excessive hepatic lipid accumulation, and mitochondria stress, thus inducing fatty liver disease and affecting the physiological condition and growth of fish (Ding et al., 2020; Jin et al., 2019a; Jin et al., 2020; Lin et al., 2018; Wang et al., 2021; Wang et al., 2020). Using functional feed additives is an effective way to relieve hepatic metabolic stress and improve fish health which has drawn considerable attention in the aquaculture nutrition field. Up to now, L-carnitine (Jin et al., 2019a), choline (Jin et al., 2019b), herb extract (He et al., 2021; Liu et al., 2021; Wang et al., 2021), and other feed additives showed positive effects on fish metabolic disorder. Bile acids (BAs) play important roles in lipid metabolism. They are synthesized from cholesterol exclusively by the liver. In the intestine, BAs act as detergents to emulsify and facilitate the absorption of dietary fats and lipid-soluble vitamins. Therefore, the objective of this study was to evaluate the effects of dietary BA supplementations on growth performance, carcass biochemical composition and Biochemical Factors of rainbow trout (Oncorhynchus mykiss).
Methodology
A 75- day feeding experiment was conducted to investigate the effects of dietary bile acids (BAs, Roneon 30%) on nutritional index, growth, carcass biochemical composition, Biochemical Factors and economic return coefficient of rainbow trout (Oncorhynchus mykiss). An experiment was designed with four treatments each with three replicates. Experimental diets were made by supplementing a control diet (BA0) with 300, 600 and 900 mg bile acid (BA) kg− 1 diet, respectively. 600 juvenile rainbow trout average initial weight of 52±5 g (±SD) were assigned to twelve 2000 L experimental tanks. Fish were sampled on day 75 and growth performance indices including Food conversion ratio (FCR), Protein efficiency ratio (PER), Specific growth rate (SGR), Condition factor (CF), and Weight gain percentage (WGP) were compared among the treatments. Also carcass composition (protein, fat, ash, moisture) and bichemical factors of serum including Aspartate transaminase enzyme (AST), Alanine transaminase enzyme (ALT), Alkaline phosphatase enzyme (ALP), Lactate Dehydrogenase, Glucose, Triglyceride, Albumin and total protein were analyzed.
Results
At the end of the experiment food conversion ratio, (<1) in the treatment of 900 mg/kg showed the best performance among the experimental treatments. The final weight (187.33±7.28 g) had a significant difference compared to other treatments(P<0.05). Specific growth rate, Condition factor, Protein efficiency ratio and Weight gain percentage were improved in fish fed with diets 600 and 900 mg/kg bile acid supplementation compered with other treatments. Also Treatments receiving bile acid supplementation had more crude protein and less ash than the control treatment and the 300 and 600 mg treatments had higher moisture content than other treatments (P<0.05). Glucose, Triglyceride, Albumin and Lactate Dehydrogenase did not change by the addition of bile acid supplementation (P>0.05). Cholesterol content was significantly higher in fish fed diet containing 900 mg/kg bile acid supplementation compared with control group (P< 0.05). Aspartate transaminase enzyme in the treatment of 900 mg/kg compared to the control group and 300 mg/kg, Alanine transaminase enzyme in the treatment of 900 mg/kg and Alkaline phosphatase enzyme in the treatment of 300 mg/kg compared to other treatments showed significant differences (P<0.05) (Tables 1- 3).
Table 1: Comparison of growth indices of rainbow trout in dietary treatments (Mean ± SD)
| Control (0 mg/kg) |
T3 (900 mg/kg) |
T2 (600 mg/kg) |
T1 (300 mg/kg) |
Parameter |
| 52.25±0.86 a |
53.70±1.71 a |
50.72±2.14 a |
52.82±1.16 a |
Initial Weight (g) |
| 172.37±3.36 b |
187.33±7.28 a |
178.02±7.16 ab |
173.85±10.1 ab |
Final Weight (g) |
| 24.31±0.23 a |
25.07±0.37 a |
24.55±0.37 a |
24.31±1.16 a |
Final Length (cm) |
| 2.14±0.04 a |
2.27±0.12 a |
2.20±0.13a |
2.21±0.17 a |
Protein Efficiency Ratio |
| 1.19±0.01 a |
1.18±0.00 a |
1.20±0.01 a |
1.20±0.02 a |
Condition Factor |
| 229.89±4.09 a |
249.01±17.06 a |
251.54±23.71 a |
229±14.90 a |
Weight Gain Percentage |
Different lowercase letters in the same row indicate statistically significant differences (P<0.05).
Table 2: Comparison of carcass composition of rainbow trout in dietary treatments (Mean ± SD)
| Control (0 mg/kg) |
T3 (900 mg/kg) |
T2 (600 mg/kg) |
T1 (300 mg/kg) |
Parameter (%) |
| 58.30±0.58 c |
58.67±0.51 ab |
59.55±0.9 b |
62.47±0.42 a |
Protein |
| 30.33±0.72 a |
30.53±0.41 a |
29.95±0.58 a |
26.86±0.69 b |
Fat |
| 8.88±0.56 a |
7.46±0.12 c |
7.52±0.31 c |
8.18±0.2b |
Ash |
| 72.92±0.47 b |
72.81±0.1 b |
73.83±0.52 a |
73.95±0.44 a |
Moisture |
Different lowercase letters in the same row indicate statistically significant differences (P<0.05).
Table 3: Effects of dietary treatments on the Serum Biochemical Factors of Rainbow trout (Mean ± SD)
| Control (0 mg/kg) |
T3 (900 mg/kg) |
T2 (600 mg/kg) |
T1 (300 mg/kg) |
Parameter |
| 103.83±9.45 a |
104.33±9.93 a |
110.5±9.53 a |
106.16±6.03 a |
Glucose |
| 361.16±62.77 a |
493.83±83.99 a |
438.66±32.06 a |
478.16±74.6 a |
Triglycerides |
| 248.66±9.67 b |
304.83±21.78 a |
278.83±15.39 ab |
283.66±17.32 ab |
Cholesterol |
| 248.16±48.28 b |
417±47.71 a |
343.83±36.17 ab |
278.5±23.96 b |
Aspartate Transaminase |
| 8.5±.61ab |
12.5±1.25 a |
10±.73 ab |
10.16±1.22 ab |
Alanine Aminotransferase |
| 519.5±40.52 b |
516.33±50.42 b |
471.83±54.1 b |
689.33±73.01 a |
Alkaline Phosphatase |
| 1.86±0.04 a |
2.03±0.04 a |
1.93±0.04 a |
1.96±0.11 a |
Albumin |
| 1556.83±279.89 a |
2646.16±745.51 a |
3269.16±724.4 a |
1642±467.74 a |
Lactate Dehydrogenase |
| 3.88±0.11 b |
4.93±0.46 a |
4.26±0.15 ab |
4.38±0.23 ab |
Total Protein |
| 2.01±0.1 b |
2.9±0.47 a |
2.33±0.14 ab |
2.41±0.15 ab |
Globulin |
Different lowercase letters in the same row indicate statistically significant differences (P<0.05).
Discussion and conclusion
The changes of serum biochemical factors as well as the relative improvement of growth and nutrition factors indicated the positive performance of using 900 mg/kg bile acid supplementation in the diet of juvenile rainbow trout, while the effects of increasing Liver enzymes, the Serum Biochemical Factors in the mentioned treatment should be studied and investigated. Bile acid supplementation could also enhance crude protein and decrease of ash and moisture in treatment of 900 mg/kg while bile type, level and fish species must be considered. This study discusses these aspects in regard to fish nutrition to help increase the inclusion of dietary fishmeal alternatives and thus enhance aquaculture sustainability.
Conflict of Interest
We wish to confirm that there are no known conflicts of interest associated with this study.
Acknowledgements
We wish to express our thanks to the chairman and experts of Shahid Motahhari Genetic and Breeding Center of Coldwater Fishes, Yasouj, Iran.
Zahra Mahmoudikia, Ahmad Imani, Ramin Manaffar, Farzaneh Noori, Reza Jalili,
Volume 33, Issue 6 (2-2025)
Abstract
Introduction
During the previous couple of decades, the world aquaculture industry has considerably developed and remained one of the fastest-growing food-producing sectors. The global increase in aquaculture production has resulted in increased worldwide demand for fish oil to meet ever developing aquafeed industry. It has been shown that terrestrial lipid sources including vegetable oils are promising alternatives for dietary fish oil due to their increased production, price stability, and availability. Incorporating vegetable oil instead of fish oil in aquafeed formulation could improve the sustainability of aquaculture development and also increase the profitability of aquaculture industry (Xie et al., 2018; FAO, 2020). The present research was conducted to elucidate the effects of different dietary MUFA contents and LA:ALA ratios, by dietary incorporation of different propositions of vegetable oils including sunflower, linseed, coconut and olive oils instead of fish oil on growth indices and muscle fatty acids profile of Oncorhynchus mykiss fed on a plant-based diet without any marine ingredients.
Methodology
This study was conducted to evaluate the effect of different dietary levels of MUFA and different ratios of linoleic acid (LA) to linolenic acid (ALA) on growth performance and muscle fatty acid profile of rainbow trout fingerlings. 650 juveniles of triploid rainbow trout with an average initial body weight of 14.5 ± 0.17 g were randomly allocated into seven triplicated experimental groups in 300-liter polyethylene tanks. Therefore, seven iso-nitrogenous and iso-lipid experimental diets including diet 1 (55.33, 1.00; dietary MUFA content and LA:ALA ratio), diet 2 (25.30, 1.00), diet 3 (55.13, 2.05), 4 (24.92, 2.03), diet 5 (54.94, 8.06) and diet 6 (24.91, 8.06) and a control diet containing fish oil, diet 7 (33.60, 5.97) were formulated. The basal diet did not contain any fish meal. The experimental fish were fed the diets for 4 months during the first stage of the trial. Afterwards, during the second stage of the trial, all experimental groups were fed diet 7, the basal diet which contained fish oil as the only dietary lipid source for one month. At the end of each stage, the fish were weighed to the nearest 0.1 g to calculate growth indices. Muscle samples were also taken after humanly sacrificing fish for fatty acid profile studies.
Results
At the end of the first four-month feeding period, there was no significant difference among various experimental groups regarding weight gain (WG), relative WG, daily weight gain (DWG), specific growth rate (SGR), and survival rate (p>0.05). Similarly, feeding various experimental groups with diet containing only fish oil as the only dietary lipid source for one month also did not result in any significant differences among the groups (p>0.05). At the end of the first stage, there were no significant differences regarding muscle SFA contents of various experimental groups (p>0.05). Muscle MUFA contents reflected dietary MUFA content so that the highest MUFA proposition was observed in treatment 1 (p<0.05). However, n-6 PUFA and n-6 HUFA contents of fish in treatments 5 and 6 fed diets contained the highest dietary LA:ALA ratio (i.e., 8.0) was the highest (p<0.05). Muscle n-3 HUFA contents of the fish fed diets with lower dietary LA:ALA diet (≤2.0) were considerably higher than treatments 5 and 6 (p<0.05). However, those fish fed with diet 7 showed the highest muscle n-6 HUFA content (p<0.05). At the end of the first experimental period, muscular contents of EPA, DHA and PUFA of all experimental groups were significantly decreased (p<0.05) comparing to those fish fed diet containing fish oil (treatment 7). At the end of the both periods, muscle n-6 PUFA/n-3PUFA was significantly increased in treatment 5 (fish fed diet containing 55% MUFA and LA:ALA ratio of 8) compared to the control group (treatment 7, p<0.05). At the end of the second feeding period, there were no significant differences regarding muscle SFA and PUFA contents among various experimental groups (p>0.05). Similar to the previous stage, muscle MUFA contents of those fish that had previously been fed diets with higher MUFA contents was higher but the difference was milder compared to the first feeding period. Muscle n-3 PUFA and n-3 HUFA contents of fish did not show any differences among various experimental groups (p>0.05). However, muscle C20:4n-6, n-6 PUFA and n-6 HUFA contents still showed significant differences among groups to the extent that treatments 5 and 6 showed the highest propositions (p<0.05). Feeding all experimental groups with the finisher diet containing fish oil could to some extent restore the muscular contents of the aforementioned fatty acids, although muscle DHA content of treatment 5 was significantly lower compared to treatment 7 (p<0.05).
Discussion and conclusions
Our results showed that different vegetable oils blends could replace fish oil in plate-sized rainbow trout feed. Complete replacement of dietary fish oil by such terrestrial oils blends with different MUFA contents and LA:ALA ratios could affect muscle fatty acid profiles of fish which were characterized by high MUFA, ArA, and LA and lower EPA and DHA contents when compared to those fish fed diet containing fish oil. Although, rainbow trout was considerably able to de novo synthesis of EPA and DHA, increasing dietary LA:ALA ratio, i.e., >2.0, resulted in decreased muscle EPA and DHA content revealing that increased dietary LA:ALA ratio might affect liver desaturation and elongation enzymes activity which finally affect muscle fatty acid deposition requiring further studies regarding the enzymes activity and expression. Such decreased EPA and DHA contents warrant further consideration in terms of the nutritional quality of fish fillet for human consumption when replacing dietary fish oils with vegetable oils. In addition, feeding the fish with a finisher diet contained fish oil for a short period could restore the muscular fatty acids profile to improve the nutritional quality of fish. The efficacy of such a feeding strategy was considerably higher in those fish previously been fed diet 2 contained 25% MUFA with LA:ALA ratio of 1.0. However, the complete conclusion warrants more detailed studies in in terms of nutrient digestion and absorption, immune competence and finally reproductive performance of fish.
Conflict of Interest
The authors declare that they have no conflict of interest.
Acknowledgment
We are grateful to the technicians and staff of the Fisheries Department of Natural Resources Faculty and Artemia and Aquaculture Research Institute, Urmia University for their sincere assistance during the experiment.
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