Iranian Scientific Fisheries Journal
Year:2020 | Volume:29 | Issue:2 |Papers Count:21

The aim of this study was to investigate the effect of different dietary protein levels on growth, survival and body composition of Hediste diversicolor. Three isocaloric diets with three different protein levels containing high protein (50%), medium protein (35%) and low protein (20%) were designed in three replicates in completely randomized design. Hediste worm larvae weighing 0. 02± 0. 005g were distributed into nine 40-L tanks with a density of 500 worms (2500 worms per m2). The worms were fed for 77 days. Results showed that final weight, final biomass (g/m2), biomass gain, specific growth rate, body weight increase and average daily growth in worms fed high protein (50%) were significantly higher than in comparison with other experimental treatments (p<0. 05). The highest survival rate was recorded in worms fed medium protein (35%) (p<0. 05). Worms fed 50% and 35% protein levels had the highest content of carcass protein that showed significant difference (p<0. 05). Significant differences were observed in contents of lipid and ash (p<0. 05). Worms fed protein at the level of 35% showed the highest level of carcass moisture (p<0. 05). The lowest (p<0. 05) feed conversion ratio and economic conversion ratio were seen in worms fed protein at the level of 50%. According to obtained findings, protein at the level of 50% (high) can be effective in enhancing of growth performance, feed efficiency, body composition of Hediste diversicolor and economic efficiency.

The establishment of aquaculture cages in the right place will be associated with the least adverse effects on the ecosystem, so the quality of sediment is very important in monitoring fish cages farming. The aim of this study was to investigate the sediments chemistry parameters around fish cage culture in the southern of Caspian Sea (Nowshahr region). Sampling was conducted in four stages of the breeding period during 2017 and 2018, underneath the cages and at 200m and 1000 m longitudinal distance in four geographical directions from the cages. Based on the results the variations in different forms of phosphorus such as Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Res.-P and TP were 1. 2-13. 8, 22-114, 12-121, 37-211, 61-2170, 150-2223, 0-937 and 203-2283 μ g/g. dw, respectively. The order of different forms of phosphorous were registered as Ca-P>Res.-P >Fe-P>Al-P>Loosely-P. The variation range of pH, Eh and TOC% were 8. 05-8. 60, (-63)-(-83) and 1. 36-7. 87, respectively. The results revealed that temperature, Eh and pH had the main role in the adsorption and release of loosely-P, Fe-P and Al-P. Comparison of 25-75th percentiles of total organic carbon (1. 97-2. 60%) with permissible threshold showed that the sediments of Nowshahr region can be classified as moderately polluted.

Different hormones are used to induce final sexual maturation in fish breeders and one of these hormones is different analogue of gonadotropin releasing hormone (GnRH) with different trade names. The aim of this study was to evaluate the biological activity of recombinant GnRH produced in the laboratory of Sari Agricultural Sciences and Natural Resources University on the induction and synchronization of ovulation in goldfish broodstock (Carassius auratus). For this purpose, 20 pairs of mature goldfish were obtained from goldfish breeding centers and transferred to wet laboratory of the Fisheries Department. Fish were acclimated to experimental conditions for 2 weeks then they were divided to 4 treatments. The first, second and third groups received 10, 15 and 20 μ g recombinant GnRH/kg body weight, respectively, as well as 20 mg metoclopramide (anti-dopamine)/ kg body weight and control group was injected by physiological saline with 20 mg metoclopramide (0. 09% NaCl. ) The results showed that the produced recombinant GnRH had the ability to induce final maturation in the studied broodstock and all groups received recombinant GnRH ovulated but none of the control group ovulated. The latency period in the broods injected by dose of 20 μ g/kg was significantly lower than the other treatments (p<0. 05). There was no significant difference in the total obtained egg and relative fecundity between treatments of recombinant GnRH (p<0. 05). The results indicated that the recombinant GnRH has a good biological activity and it can be introduced as a suitable alternative for the treatment of reproductive disorders in goldfish.

The aim of this study was to investigate of betaine effect on growth performance, hematology and resistance of Schizothorax zarudnyi to salinity stress. For this purpose, 120 fish (6. 58± 0. 29 g) were fed with levels of 0 (control), 0. 5% (treatment 1), 1% (treatment 2) and 2% (treatment 3) 2 times per day for 8 weeks. At the end of the period, the fish were biometric and exposed to 20 g. L-1 salinity stress for two hours. Results of this study showed, significant difference in growth parameters (Mean of final weight and length, SGR, CF and FCR) between fish fed betaine supplementation diets and control group (p<0. 05). In addition, the results of blood factors indicated that betaine had no effect on hematocrit, hemoglobin, red and white blood cells count and no significant difference was observed between treatments and control(p>0. 05). Resistant to salinity stress in Schizothorax zarudnyi were fed to betaine, was more than the control group. Based on the results of this study, it seems that betaine supplementation diets can increase the growth and resistance of Schizothorax zarudnyi.

The aim of this study was to evaluate the performance of plant nano-gels as a new adsorbent and to remove nitrite at low cost. At first, plant nano-gels (nano bagasse, chitosanfunctionalized nano-fiber and lignocellulose nano-fiber) were prepared by mechanical and top-down mechanism. Batch system medium was designed to measure the adsorbent optimum. Then isotherm and synthetic were calculated to estimate absorption coefficients. The optimum amount of adsorbent weight for each nano gel was: 0. 1 g for nano bagasse and lignocellulose fiber; 0. 3 g for modified nano fiber; 4 for nano bagasse and lignocellulose fiber and 5 for modified nano fibril; also initial concentration and the time for all adsorbents was 25 mg /l and 60 min. According to the equilibrium equations, the most consistent were considered with Langmuir, Freundlich and Temkin models. Results showed that the highest nitrite removal efficiency was related to functionalized nano-fiber with 93. 1%; for nanobagasse it was 65. 51% and for lignocellulose nano-fiber was 68. 96%. Eventually, the plant nano-gels can be used as bio-filters in the effluent system of fish farm.

In this study, for the first time, lanternfish gelatin (Benthosema pterotum Alcock, 1890) was extracted and the composition (moisture, ash, protein), gel strength, gelling and melting temperature of extracted gelatin was investigated and compared with those of the commercial bovine gelatin purchased from market. The two gelatin samples were also compared in terms of color properties. Moisture and ash content of lantern fish gelatin were significantly higher than commercial gelatin. The result of measurement indicates that moisture and ash content of lantern fish gel were 8. 2± 0. 1% and 3. 2± 0. 1%, respectively. Protein content of the bovine gelatin (91. 71± 0. 1 %) was significantly higher than lantern fish gelatin (86. 3± 0. 1 %) (p<0. 05). The gelling temperature and gelling time of the lantern fish gelatin (135 sec± 2. 0, 23± 0. 5° C), due to its low hydroxyproline content, was significantly lower than bovine gelatin (150 Sec± 1. 0, 26± 0. 5° C) which is due to fish gelatin nature. A significant difference between the gel strength of lantern fish (45± 1. 00 gr) and bovine gelatin (240± 1. 2 gr) was observed (p<0. 05) and also bovine gelatin had better quality in terms of color factors than the gelatin extracted from lantern fish. Overall, lantern fish gelatin can be used in many biotechnological industries, as an economical and halal gelatin source, instead of pig and bovine gelatin.

Bensulfuron methyl is one of the most widely used herbicide which is used in agricultural fields, especially rice fields. The present study investigated the toxicity of Bensulfuron methyl in Cyprinus carpio for the first time. To this aim, in order to determine the range Finding Test of Bensulfuron methyl, the fishes were randomly divided into 8 groups including 0, 0. 01, 0. 05, 0. 1, 0. 5, 1, 2 and 4 g/l Bensulfuron methyl and fish mortality was recorded at 24, 48, 72 and 96 hours. After determination of the range Finding Test, the fishes were randomly divided into 5 groups in three replicates at concentrations of 0, 1. 2, 1. 4, 1. 6 and 1. 8 g/l of Bensulfuron methyl and the fish mortality were recorded at 24, 48, 72 and 96 hours. Then, the data were analyzed using Probit analysis by SPSS software and LC1-99 including LC1, LC10، LC30، LC50، LC70، LC90 were calculated. The results showed that fish mortality increased with increasing concentration of Bensulfuron methyl and exposure duration, and the lethal concentration of Bensulfuron methyl decreased with increasing exposure duration. So that, the LC50 at 24, 48, 72 and 96 hours were 1. 86, 1. 82, 1. 75 and 1. 62 g /l, respectively. In this study Maximum Allowable Toxicant Concentration (MAC), No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) of Bensulfuron methyl were calculated 0. 162, 0. 162 and 1. 41 g/l, respectively.

The Oman Sea (Makoran) has always been influenced by the monsoon currents, and this phenomenon is a natural stressor for species inhabiting the marine ecosystem, including bivalve molluscs. To study the diversity of subterranean bivalves sampled from three areas of Ramin, Beris, and Pasabandar, a total of 10 stations, in the winter of Pre-Manson, Mansoon and Post Mansoon in 2018. In this study, 8 families of bivalve communities were identified that the Veneridae family had the highest frequency in all three time periods. According to the results, in post-monsoon bivalves were higher with 46. 19% abundance (11400 abundance) than premonsoon month, 27. 06% (6660 abundance) and the monsoon period with 26. 74% abundance (26. 74%) 6680 m2), which also showed significant difference analysis of variance. The mean of Shannon index in pre-monsoon, monsoon and post-monsoon were calculated 2. 22± 0. 04, 2. 21± 0. 1 and 2. 51± 0. 11, respectively, but no significant differences were observed between different periods. Mean dominance index observed in pre-monsoon, monsoon and postmonsoon was calculated 0. 86± 0. 06, 0. 86± 0. 05, 0. 9± 0. 01, and between post-monsoon and other periods, respectively. The mean eveness index was calculated as 0. 959± 0. 01, 0. 951± 0. 02, 0. 948± 0. 01 and the difference between the monsoon and pre-monsoon periods were not significant. In general, it can be said that various factors are considered as parameters controlling the abundance and diversity of bivalve communities of different regions and stations in the coastal waters of Chabahar Bay, including the most important ones. It can be noted the sampling time and the winter monsoon current.

At this study, the effects of adding Iranian acorn flour on growth performance, carcass composition and resistance to salinity stress of common carp were investigated. Experimental diets included: 1) without acorn and not autoclaved diet; 2) without acorn and autoclaved diet for 2 minutes; 3) without acorn and autoclaved diet for 10 minutes; 4) with 10 percent acorn and not autoclaved diet; 5) with 10 percent acorn and autoclaved diet for 2 minutes; 6) with 10 percent acorn and autoclaved diet for 10 minutes. After 6 weeks results showed that weight and total length in the treatment 2 were higher than the rest. This increase was significantly higher than all treatments except 4 (p<0. 05). Autoclaving reduced carcass protein and increased its moisture contents significantly and this effect intensified with an increase in the duration of autoclaving. Short-term autoclaving caused a significant increase in carcass fat while long-term autoclaving resulted its significant reduction. Adding acorn flour into the diet reduced amounts of carcass protein and fat and increased its moisture content significantly. Accordingly, although there was no significant difference between fish weights of treatments 1 and 4, replacement of wheat flour with acorn flour at 10% of diet was undesirable. In not autoclaved or shortterm autoclaved diets, oak acorn flour reduced carcass ash significantly. In salinity stress test, the highest and lowest survival time were observed in the treatment 2 and treatments 1 and 6, respectively. When autoclaving (heat) was used in food production, the addition of oak acorn flour to the diet significantly reduced survival time at the salinity stress. Overall, considering the growth performance, carcass composition and resistance of carp to stress, it is recommended to study oak acorn flour consumption at levels less than 10% of the diet.

Proximate, fatty acid compositions and nutritional quality indices of lipids between the caviar of wild and farmed Caspian Sea Beluga (Huso huso) sturgeon and their cardiovascular effects have been compared. Protein, lipid, moisture and ash were analyzed by using standard methods of proximate composition analysis and fatty acids profile determined by gas chromatography method. The fatty acid composition varied in both wild and farmed Beluga caviars, but they did no differ in proximate compositions. The most notable difference (p<0. 05) was the higher concentration of linoleic acid (C18: 2n6) in farmed Beluga caviar (8. 32%) than wild ones (0. 37%). The total ω-3 in wild caviar (38. 42%) had no significant difference from farmed ones (30. 42%) (p>0. 05), but the content of total ω-6 was significantly higher in farmed (17. 39%) samples than wild ones (13. 27%). The ratio of ω-3 /ω-6 was higher in wild sample (2. 9) from farmed ones (1. 75) (p<0. 05). Between wild and farmed caviars respectively, the atherogenic, (0. 29, 0. 28), thrombogenic (0. 18, 0. 21), Hypocholesterolaemic/Hypercholesterolaemic (2. 45, 2. 52) Polyene (1. 73, 1. 46) and Peroxidisability (326. 86, 269. 03) indexes contents had no significant differences (p>0. 05). The present study indicated that the caviar from farmed Beluga like wild ones could be considered as a good food sources, besides, it has good balanced with lipid nutritional quality indices to cardiovascular prevents and finally it has important impact on protecting wild population from elimination.

In order to increase the knowledge of the probiotic effects on reproductive indices of fish, this study was conducted to investigate the effects of different levels of probiotic Lactobacillus plantarum on gonadal development and sexual maturation in zebrafish (Danio rerio). Some 720 zebrafish were fed the experimental diets in four treatments such as: 0%, 0. 5%, 1. 5% and 3% probiotic diets for 40 days. Based on the measurement of reproductive indices in this species, the maximum absolute fecundity was observed in the diet containing 3% probiotic, which was significantly different from the control treatment and the diet containing 0. 5% probiotic. Based on relative fecundity index, the control treatment showed the lowest fecundity rate compared to the other treatments. The gonadosomatic index data showed the utmost gonadal index in the diet containing 3% probiotic compared to the other treatments, which was significantly higher than the control and 0. 5% probiotic treated diets, but it did not show any significant difference with the diet fed 1. 5% probiotic. Histological examination of gonads in males and females showed gonads development and complete sexual maturity in treatments fed 3% and 1. 5% probiotic levels. The present study indicates that probiotic Lactobacillus plantarum at 3% level will have the best effect on reproductive and gonadal development parameters in zebrafish.

The purpose of this study was to present a model of export performance development of farmed shrimp in Iran. The research method is qualitative and is based on Grounded Theory. Theoretical sampling was performed using snowball technique based on which, 16 interviews were conducted with the scientific and practical experts of the Iranian shrimp industry (Fisheries Organization managers, Iran's Aquaculture Production and Trade Union and the top companies in the field of shrimp export). Results of data analysis of the interviews through open, axial and selective coding process using Atlas ti. software has led to the surface of the export performance model of Iranian farmed shrimp, based on which, Causal Conditions, Core Phenomenon, Strategies, Contextual Factors, Intervening Conditions, and Consequences were identified. In total, 17 main categories, 56 subcategories, and 138 concepts fall into six axial categories. The researcher has reached a theoretical saturation in regard to all the concepts in question. Also, in later stages, by reviewing the concepts and presenting the model to the experts’ for the second and third times, the acceptability of the model was assured. As a result, components, indicators, and areas influencing the central phenomenon of "export performance of farmed shrimp" are identified and strategies are proposed to reach the expected results and outcomes.

Rainbow trout (Oncorhynchus mykiss) is an exotic fish in the inland waters of Iran and little is known about this species in Iranian natural waters. In this study, some biological characteristics of rainbow trout such as GSI and absolute and relative fecundity were examined in 355 specimens collected monthly from Beheshtabad River of Chaharmahal and Bakhtiari Province during April 2013 to March 2014. Total length of females and males ranged from 17. 1 to 40. 2 cm (26. 05± 4. 54 SD) and from 15. 5 to 40. 3 cm (24. 9± 5. 93), respectively. The age of male and female rainbow trout ranged between 1+ to 4+ and 2+ to 5+ years, respectively. The most frequent age groups were 1+ and 2+ in males and females, respectively. Sex ratio was 1M: 1. 3F. Based on macroscopic gonad observation, maturation cycle consisted of five stages; immature, developing, spawning, regressing and regeneration phases. The gonadosomatic index indicated that reproduction of rainbow trout in the Beheshtabad River occurred in October and Junary for males and in September and Jaunary for the females, with the highest mean value of 3. 28 and 4 in November and Jaunary for males and 4. 22 and 3. 48 in September and Jaunary for females. Oocyte diameters ranged from 0. 125 to 3. 5 mm. Absolute fecundity ranged between 680 and 3890 (1860± 170) eggs. Relative fecundity ranged between 1900 and 9000 (4600± 360) eggs/Kg body weight. It seems that this species has been able to adopt very well to the river conditions.

This study was done to investigate the effect of microencapsulated and non-encapsulated spirulina (Spirulina platensis) powder on the antioxidant enzymes activity and nutrient digestibility of broiler chicks for 6 weeks. A total of 360 one-day old broiler chicks (male) Ross 308 strain was divided into 9 treatments, 4 replicates (10 chicks in each replicate) in a completely randomized design. Experimental treatments include: basal diet without any additives (negative control), basal diet + antibiotic (positive control), 1-basal diet + vitamin E, 2-basal diet + 0. 33% spirulina microencapsulated, 3-basal diet + 0. 66% spirulina microencapsulated, 4-basal diet + 1% spirulina microencapsulated, 5-basal diet + 0. 33% nonencapsulated spirulina, 6-basal diet + 0. 66% non-encapsulated spirulina and 7-basal diet + 1% non-encapsulated spirulina. Results showed that the blood super oxide dismutase activity increased in chicks fed with encapsulated spirulina powder and non-encapsulated spirulina powder at the level of 1 percent (p<0. 05). But the activity of catalase and glutathione peroxidase enzymes did not show any significant difference (p>0. 05). The effect of experimental treatments on nutrient digestibility showed that no significant different experimental groups (p>0. 05). The addition of spirulina powder and encapsulated spirulina powder increased antioxidant activity in the diet of Ross 308 broiler chicks.

Persistent organic pollutants are a wide group of toxic and dangerous compounds. These organic compounds are chemically and physically stable even beams. In this study an analysis method for simultaneous determination of 18 persistent organic pollutants including eleven Organochlorine pesticides (OCPs): HCB, Dieldrin, Methoxychlor, α-, ϒ-Chlordane, α-, β-Endosulfan and o, p’-DDE, p, p’-DDE, o, p’-DDT, p, p’-DDT and seven indicator Polychlonitated biphenyls (PCBs); IUPAC nos.: 28, 52, 101, 118, 138, 153, 180 congeners were determined in Rainbow trout by GC-MS/MS in MRM monitoring mode and LLE extraction. The validation results showed the calibration curves over the concentration range of 0. 1-30 ng/mL for PCBs and 0. 5-150 ng/mL for OCPs were linear and coefficient of determination (r2) ranged between 0. 990-0. 999. The LODs and LOQs for POPs studied were between 0. 6-8. 3 and 2-25 ng/g, respectively. The average recoveries obtained for analytes in five different spiked levels (1-10 ng/g for PCBs and 5 times for OCPs) were in the range of 73%-112%. The relative standard deviations of POPs in fish were in the range of 1. 4-17. 9% for all of the concentration levels. The ranges of uncertainty were reported between 2. 77%-30. 88%. The results indicated the presence of organochlorine pesticides in trout samples and the highest level of contamination was related to p, p’-DDT with average values of 113 ng/g ww (wet weight). Dieldrin and p, p’-DDE were among the next level of contamination with mean values of 13. 3 and 10 ng/g ww, respectively. Study of other OCPs in the trout samples indicated the presence of α-, ϒ-Chlordane, o, p’-DDE, o, p’-DDT and HCB in which the amount were lower than the limit of quantitation (LOQ) of the method. OCPs residues were lower than maximum residue levels set by European Council Directives, SANTE (2017) No. 11813. Also, the study of PCBs in trout samples indicated the presence of only PCB 28 and its amount was lower than maximum residue levels set by European Commission Regulation (EU) (2017) No. 644.

The purpose of the present study was to determine the dietary organisms in the earthen ponds and the preferences of the fish in the consumption of them. Sampling for 6 weeks was carried out at 6 times in two 4 hectare ponds with 3 sample points in each pond. In order to evaluate zooplankton and benthos from the contents of the stomach, 180 juveniles were sampled. The Results demonstrated that. The highest abundance of food organisms in ponds was Copepoda and naupli with 49. 58 % and the highest amount of them in the stomach contents of of juvenile sturgeon was in the case of Cladocera with 61. 19% and Chironomidae with 25. 27%. Ivlev's index (E) to Cladosera, Ostracoda and Chironomidae were positive. On the other hand, the value of E index for Copepoda was negative. The results of present study showed that, juveniles' sturgeon have a high tendency to feed from Cladosera, Ostracoda and Chironomidae. So that, Cladosera and Chironomidae are among the main food and Ostracoda is considered as an occasional food. When Cladosera, Ostracoda and Chironomidae biomass decreased in the ponds, sturgeon feed from Copepoda.

The Gargar River is the eastern brunch of the Karoon River, which is separated in north of Shoushtar by regulatory dam (Bandmizan) from its western branch, Shotaeit, and is about 78 km later, join to the Shotaeit and Dez and create the big Karoon. This river, while supplying drinking water to Shoshtar, Haftgel, and part of Ramhormoz and its villages, is one of the great poles of the province's fish culture. The aim of this study was to evaluate the microbial quality of surface waters of the Gargar River, compare the microbial contamination at upstream and downstream stations as well as comparisons with EPA standards to determine different uses. For this purpose, 6 stations were selected and sampling was conducted monthly within one year and microbial indices including total bacterial count, total coliform count and fecal coliform count were evaluated. The results showed that maximum of the 3 microbial indicators was at the station 2, after the sewage discharge of Shushtar (respectively 15. 24×103 CFU/mL, 68181. 82, 3380. 91MPN/100mL) and the minimum value was at the station 1 at the upstream river (respectively 2. 8×103 CFU/mL, 2627. 27, 1062. 73MPN/100mL). The microbial indices varied depending on seasonal variation, sampling time and location and the final results of this study showed that the water quality of river is inferior and not suitable for human use.

Long-chain polyunsaturated fatty acids (such as Arachidonic acid, ARA, C20: 4 n-6) have unique roles in controlling and regulating growth performance, lipid metabolism, cell membrane fluidity, and immune function in fish. This research was conducted to produce higher quality and resistant zebrafish using arachidonic acid diet to achieve the best growth and survival rate. Five experimental groups were established and fed diets with different levels of ARA corresponding to 0 (control), 0. 5, 1, 2 and 4% of total fatty acid. Zebrafish larvae (20-days post-fertilization) were fed ad libitum 5 times daily for 10 weeks. Both weight and length were recorded to determine growth indices. Although there were significant differences in general growth demographics (length/weight) after the 10-week feeding trial, no significant differences in the overall survival rate of Zebrafish. Increase in dietary Arachidonic acid (up to 2%), maximum final weight (0. 38 ± 0/01 g), body weight gain (0. 32± 0/16), body weight gain percent (613. 42 ± 28/44), daily growth rate (0. 46 ± 0/02) and the lowest feed conversion ratio (2. 24 ± 0/05) were higher than other treatments. The results show that ARA has a significant influence on the growth factors of Zebrafish.

In the present study, whiteleg shrimp postlarvae were exposed for 21 days with sublethal concentrations of silver nanoparticles containing treatment 1: (%10 LC50 (0. 39 mg/L AgNP), treatment 2: (%25 LC50 (0. 97 mg/L AgNP), Treatment 3: (%50 LC50 (1. 95 mg/L AgNP)and treatment 4: (%75 LC50 (2. 92 mg/L AgNP) and one treatment was considerd as control treatment. during 21 days. At the end of the experiment, gill, muscle and hepatopancreas tissue samples were samples to measure changes in levels of metabolic and antioxidant enzymes. According to the results, the enzyme activity of alanine aminotransferase and aspartate aminotransferase in hepatopancreas and gills showed a significant increase compared to the control (p<0. 05), but there was no significant difference in muscle (p>0. 05). Alkaline phosphatase activity was only decreasing in hepatopancreas, which was significantly higher than control (p<0. 05). Lactate dehydrogenase level was not significantly different in all tissues (p>0. 05). Among the antioxidant enzymes, the activity of superoxide dismutase in hepatopancreas and gills showed a significant decrease (p<0. 05) compared to control, but glutathione peroxidase had no significant difference (p>0. 05). The level of glutathione Stransferase was increased only in hepatoconal tissue and in treatment 4 significantly (p<0. 05). The level of glutathione S-transferase was increased only in hepatopancreas tissue and in treatment 4 significantly (p<0. 05). Overall, results showed that shrimp exposure to high concentrations of silver nanoparticles causes oxidative damage, especially in the hepatopancrease tissue.

Antibacterial packaging materials are nowadays considered as one of the new technologies to prevent the spread of spoilage and pathogenic microorganisms through food. The present study was conducted to investigate the antimicrobial effect of chitosan coating with the aqueous extract of Withania coagulans to increase the shelf life of silver carp (Hypophthalmichthys molitrix) fillet. Fish fillets were kept in 6 treatments and 3 replicates for 18 days at 4° C. Treatments included: uncoated treatments (control), 0. 5% extract, 1% extract, 1% chitosan, 1% chitosan with 0. 5% extract and 1% chitosan with 1% extract. The microbial characteristics [Total Bacterial Counts (TBC) and Psychrophilic Total Bacterial Counts (PTC)] of the samples were studied at 0, 3, 6, 9, 12, 15 and 18. During the storage period, all treatments containing chitosan coating and extract had significant differences in bacterial evaluation with control treatment (p<0. 05). The highest bacterial indices of TBC and PTC up to day 18 of silver carp fillet storage in the refrigerator were in the control treatment (8. 03 ± 0. 02 and 8. 16 ± 0. 02) and the lowest in the 1% chitosan coating with 1% Withania coagulans extract (5. 79 ± 0. 01 and 6. 10 ± 0. 03), respectively. The results of current study showed the strong antibacterial effect of 1% chitosan edible coating with 1% whey extract which had a significant effect on the reduction of TBC and PTC and also increasing the shelf life of the coated fillets.