Iranian Scientific Fisheries Journal
Year:2019 | Volume:28 | Issue:6 |Papers Count:19

Probiotics, as a live microbial dietary supplement, play an important role in the growth and activity of the host digestive enzymes by balancing the gut microbial population. The present study was conducted with 4 treatments and 3 replications including diets containing 1×106, 3×106 and 5 ×106 (cell/ g feed) and control (basal diet without yeast) to evaluate the effect of different levels of dietary supplementation of Saccharomyces cerevisiae on growth performance, body biochemical composition and digestive enzymes activities of grey mullet, Mugil cephalus. The fish (5. 56± 0. 65 g) were randomly allocated into 12 fiberglass tanks at a density of 20 individuals per tank with three replicates for each treatment and fed with the experimental diets for 60 days. The results indicated that the diet at 5×106 yeast cells/ g( significantly improved weight gain (240. 36± 13. 57%), final weight (919. 28± 1. 55), protein efficiency (10. 01± 0. 56%) and survival (94. 40± 13. 57%) compared to the control and treatment 2 (p<0. 05). Also, the highest activity of amylase (199. 50± 17. 70 U/mg protein) and protease (362. 50± 13. 52 U/mg protein) were observed in 5×106 yeast cells/ g diet (P<0. 05). This study shows that the use of S. cerevisiae 3×106 and 5 ×106 yeast cell/ g feed can have positive effects on growth performance, feed utilization, body chemical composition and digestive enzymes activities of M. cephalus.

Effects of using various ratios of C: N in biofloc system on growth performance, feeding indices and culture water quality of common carp with mean weight of 14. 17± 0. 36 g were investigated during 90 days in experimental treatments including control (no extra carbon source) and four treatments with different C: N ratios of 11, 15, 19 and 23 each with 3 replicates. The increase in C: N ratio had a significant effect on growth and feeding indices of cultured common carp in treatments (p<0. 05). The highest final weight and weight gain, the lowest FCR and the highest SGR were observed in C: N ratio of 19. No significant difference was observed in survival rate among different treatments indicating that the culture condition was suitable for common carp in this biofloc system. Hepatosomatic and visceral indices did not show significant differences between treatments with different C: N ratios (p> 0. 05). Water quality indices including DO, pH, TDS, EC, TSS, FV, TAN, nirtite and nitrate showed significant differences in biofloc system with different C: N ratios (p<0. 05). The mean values of FV and TSS in biofloc system increased with increasing C: N ratio. The variation pattern of the mean TAN and nitrite were the same as each other and reverse to the trend of TSS and FV showed a decreasing trend with increasing C: N ratio. These trends indicate the significant removal of nitrogenous compounds by bioflocs. In conclusion, using C: N ratio of 19 with molasses as carbon source in biofloc system could be recommended to improve water quality, growth and feeding performance of cultured common carp.

Removing ammonia in recirculating systems is necessary to increase efficiency and reducing ammonia toxicity. So, the select appropriate type of media to reduce is very important. In this study, four different materials (bio-Ball, wood flake, seashell, and natural pumice) as media and guppies as fish sample were used for 40 days. The results showed that the level of ammonia decreased in all media, but this reducing was higher in wood flake than other treatments. Also, the growth indices showed that the fish in the aquarium with wood flake and seashell had a better performance than other media. Accordingly, it can be concluded that due to the better performance of wood flake to reduce ammonia and make more optimal environmental conditions than other media, it can be an appropriate media for bio-filters.

Planning to increase the per capita consumption of shrimp in the country, like any other food, will not be possible without an examination of consumer's behavior and the recognition of their needs, interest and tastes. The purpose of this study was also, to assess the priorities of shrimp consumers and their barriers to consumption in the country. The statistical population of the study was the whole country that was selected by random sampling of 10 cities and completed 1000 questionnaires corresponding to the population of the mentioned cities. Questionnaire data were transferred to the SPSS 20 software and ranking of desired factors were determined by Friedman test. The results showed that the three first priorities of consumers were quality, packaging and experimental records. Other priorities were positive and negative beliefs, supplying and processing model, price, availability, convenience of cooking, consumer income, and time-consuming, respectively. In term of the quality, packaging, positive and negative beliefs and processing model, the first priority of consumption society was smell, brand name, tissue contamination and fried shrimp (packaging), respectively. The study of barriers to consumption of this product in the country showed that the prices (expensive) of shrimp, its smell, and disproportion of shrimp prices with people's incomes were the first three barriers to buying and consuming shrimp in Iran, respectively. In this research, per capita consumption was calculated 98. 5 and 487 grams for the statistical population and consumption society respectively. According to the results, in order to increase the per capita consumption, this industry's managers should concentrate their activities on quality and packaging indicators and final price of product.

In this study, the effect of diets containing different levels of Pontogammarus maeoticus extract as natural nutrient attractant was investigated on growth indices, chemical composition and mucosal Immunity of Rutilus kutum. For this purpose, fish with an average weight of 0. 35± 0. 067 were stored in 100L fiberglass tanks containing 30 liters water with a density of 20 fish per tank for eight weeks. To perform this study, Gammaridae extracts were mixed with distilled water in three concentrations: 1: 25 (25%), 1: 50 (50%), 1: 75 (75%) and two percent of each dilution was added to manual meals before each feeding. This experiment was performed as four triplicated treatments. Larvae were fed four times a day. At the end of the culture, growth indices such as: mean body weight gain, specific growth factor, food conversion ratio, survival, chemical analysis of carcasses and some mucosal immune parameters including; lysozyme, immunoglobulin, alkaline phosphatase and protease were studied. The results showed that although growth factor and carcass analysis were improved in all treatments (25%), this increase was not significant compared to the control (p>0. 05). All Mucus immune factors significantly increased in all treatments compare to control (p<0. 05). The result of this study showed that the Gammaridae extract had no significant effect on the improvement of growth performance, but increased the immunity of Rutilus frisii in culture conditions.

In this study, the effects of both mineral and nanoparticles selenium were investigated on growth performance, liver enzymes, and antioxidant status of yellowfin porgy, Acanthopagrus latus. A total number of 300 fish (average weight = 25± 3 g) were randomly distributed in five groups according to according to diet: control (basal diet), nanoSe (1 and 1. 5 mg/kg-supplemented diet) and sodium selenite (1 and 1. 5 mg/kg-supplemented diet). Fish were fed with experimental diets for six weeks. At the end of the experiment, liver and blood samples obtained to assay the liver and antioxidant enzymes activities. The results showed that addition of 1 and 1. 5 mg/kg nanoSe to the diet promoted growth, as weight gain increased significantly in A. latus fed by nanoSe (p<0. 05). Also, the highest glutathione peroxide and catalase activity were recorded in treatment containing nanoSe (p<0. 05). While the lowest ALT activity were seen in 1. 5 mg/kg nanoSe (p<0. 05). The lowest level of Malondialdehyde (MDA) was in the liver of fish fed by nanoSe, while there were no significant differences with the control and Sodium Selenite groups (p>0. 05). Our findings showed that Selenium nanoparticles had beneficial effects on growth performance and antioxidant defense system of A. latus.

This study was conducted to investigate the effects of temperature (24 and 30 ˚ C), magnesium and iron removal on Arthrospira plantensis growth and biomass in vitro For this purpose two culture media have been used: Zarrouk and Jourdan culture medium. Removal of magnesium and iron were performed in six treatments and two controls with three replications. Temperature experiments were performed in two treatments with three replications for two mentioned media. Optical density of samples was measured daily by a spectrophotometer at 560 nm. In addition, biomass was measured in g/L at two stages (in 7 and 14 days). pH was measured daily. The results showed that in Zarrouk culture medium (control), mg free treatment and mg-fe free treatment have the highest biomass in day 7 (0. 88 g/L). In day 7, among all treatments (mg free, fe free, mg-fe free), only mg free treatment showed statistically significant with standard culture medium (Zarrouk), (p<0. 05). In day 14, the mg free treatment showed the highest biomass (0. 95 g/L), but there was not significant difference between treatments (mg free, fe free, mg-fe free) and standard culture medium (Zarrouk), (p<0. 05). In Jourdan culture medium, control and fe free treatment have the highest biomass (0. 7 g/L) in day 7; and fe free treatment has the highest biomass (1. 27 g/L) in day 14; but there was not significant difference between treatments (mg free, fe free, mg-fe free) and standard culture medium (Jourdan), (p<0. 05). Regarding to temperature effects, in Zarrouk and Jourdan media, the highest growth observed at 24˚ C and 30˚ C, with 2. 74 and 2. 14 g/L respectively. There was significant difference between treatments (24 and 30˚ C), (p<0. 05). results indicated A. plantensis can be cultivated in large scale by removing magnesium and iron from medium by this way, we could reduce the culturing cost of A. plantensis.

This research investigated the influence of selenium nanoparticles (SeNPs) on the reproductive performance of female rainbow trout (mykiss Oncorhynchus) broodstocks. A total of 120 female broodstock were selected from breeders of the Shahid Motahary Coldwater Fishes Genetic and Breeding Research Center. After adaptation, fish were divided into four treatments in three replicates. Fish were fed diets containing 0 (control) 0. 5, 1 and 2 mg SeNPs per kg of diet for 60 days. Eggs quality parameters such as fecundity, fertilization rate, eyed egg rate, hatching, etc. were evaluated. The highest fertilization rate was observed in fish fed with 2 mg selenium (99. 30%), which had a significant difference with control groups (p<0. 05) but did not show any significant difference (p>0. 05) with fish fed 0. 5 mg and 1 mg SeNPs. Broodstocks fed with 2 mg SeNPs had the highest absolute fecundity, which had a significant difference with groups fed 1 mg SeNPs (p<0. 05), but did not show significant difference with other two treatments (p>0. 05). ) The highest and the lowest relative fecundity were seen in group fed 2 mg SeNPs and 1 mg SeNPs, respectively. However, there was no significant difference in relative fecundity between treatments (p>0. 05). The highest egg diameter was in fish fed 0. 5 mg SeNPs. Egg diameter in the control group, fish fed 2 and 1 mg SeNPs, were 5. 39, 5. 39 and 5. 40 mm, respectively). There was no significant difference for egg diameters among gruops (p> 0. 05). The highest and the lowest mean total egg weight were in group fed 0. 5 mg SeNPs and 1 mg SeNPs, respectively, and no significant differences were observed between treatments (P >0. 05). The highest percentage of hatching was observed in groups fed 2 mg SeNPs, which had a significant difference with other treatments (p <0. 05). The highest survival rate was observed in groups fed 2 mg SeNPs too, which showed no significant difference with other treatments (p >0. 05). Increase in the survival rate associated with an increase in the concentration of SeNPs. In general, inclusion of SeNPs in diet, improve the quality and quantity of eggs and reproductive function (fertilization, eyed rate and hatching) in rainbow trout breeders.

Reservoirs are artificial lakes that have been created by humans for specific purposes. Water reservoirs has different uses which the most important are: municipal water supply, agricultural irrigation, aquaculture, power generation and etc. According to increasing of water demand the accurate study of water resources, determination of their pollutants, prevention, pollution control and optimal use of available water resources are required. Saymareh Dam is located about 40 km northwest of DARREH SHAHR in ILAM province. This dam was constructed with the aim of producing electric power, controlling and regulating of river floods. The aim of this study was to survey on the bacterial contamination of Seymareh Reservoir and its relationship to some water physical and chemical factors. According to the geographical and hydrological status of the reservoir, five stations (one station near the water entrance to the lake, 3 stations at the beginning of the lake, middle and near the crown, and one station after the reservoir) were sampled 8 months in 3 seasons of year for bacteriological, physical and chemical evaluation. Water quality standards for microbiological sampling were used. Then microbial tests including total bacterial count, total coliform count, fecal coliform and fecal streptococcus count were performed. In each station simultaneous measurements of some physical and chemical parameters of water (temperature, dissolved oxygen and pH) were also evaluated. The results showed that the highest total bacteria counted during sampling at station 5 (after reservoir) and the lowest rate at station 4 (before the reservoir's crown). Also the average of total and fecal coliform was the highest at station 5 in all sampling seasons and the lowest in station 2. The stations grouping in this three indices showed that the entrance and outlet stations of the reservoir (1 and 5) are in the same group and the stations located on the reservoir (2, 3 and 4) are in the other group that showed a significant difference (p<0. 05). In the Pearson test, correlation between water temperature and pH changes with the number of total bacteria and fecal coliform was positive and with the total coliform was negative, while dissolved oxygen showed a negative correlation with three bacterial indexes. In comparison to the bacterial parameters with available aquaculture standards, the water of this reservoir is suitable for fish production in all seasons.

The changes in biological structure and growth of common kilka were investigation during 2008-2017 in the Iranian waters of the Caspian Sea. Kilka fishing ships discharged theirs catch in three parts: Babolsar, Amirabad and Anzali. The sample based on the length of 5 mm were classified. Fork length ranged from 52. 5 to 142. 5 mm and mean (± SD) 101. 9± 10. 5 and fish fork length 92. 5-112. 5 mm of the population have been dominant 81(%) (n= 49759). The slight fluctuations in the average length with values were between 100 and 105 mm. During this period, fish of +3 and +4 years old have been dominant with frequency of 80-70%. The stability length and weighted mean of generation growth rate was indicative of relative stability and the average age of common kilka stability, the stability of the population are descendants entered and confirmed. The results showed that in the year 2008 the frequency of young fish 1-2 years was 15. 2% of the catch, but gradually in the following years, the abundance of these fish in the hake decreased, so that in 2017, only 10% of the catches were allocated. Pressure on young fish stocks is an opportunity to rehabilitate stocks of this species.

This study was conducted to evaluate the effects of replacing fish meal with barley protein concentrate (BPC) on digestive enzyme activity and hepatic enzymes of Caspian salmon (Salmo trutta caspius), with initial weight mean 16. 53± 1. 1g, in a 8 week study in a design completely randomized with 5 treatments, each with 3 replications. Experimental diets consisted of control diet (without barley protein concentrate) and four diets containing levels of 25, 50, 75, 100% barley protein concentrate. At the end of the experiment, ALP, AST and ALT levels were significantly different in different experimental treatments (p<0. 05). However, there was no significant difference in LDH between different treatments (p>0. 05). There was no significant difference in Pepsin enzyme activity between fish that fed with experimental diets up to 75% replacement and control treatment (p>0. 05). The activity of Chymotrypsin and Aminopeptidase in different treatments showed a significant difference compared to control (p<0. 05). There was no significant difference in in Trypsin and alkaline phosphatase activity between fish that fed with experimental diets up to 50% replacement and control treatment (p>0. 05). The activity of amylase and lipase enzymes showed a significant difference between treatments with different levels of barley concentrate (p<0. 05). Digestive enzymes decreased at higher replacement levels, but in the middle levels of replacement, there was less effectsin pancreatic enzymes. Therefore it can be concluded that BPC levels up to 50% of the diet are tolerable for the Caspian salmon, but when it goes higher than this level, will probably result in an increase in anti-nutrients, a decrease in nutrient uptake, low diet palatability, and have adverse effects on fish growth.

This study was done after report of some mortality in one Sturgeon fish farm (Acipenser baeri) in Sari (north of Iran) during June-July 2011. Sampling was done on 20 fish and waters from selective farm for detection and identification of its agent. After recording the clinical observation, necropsy, bacterial cultures, biochemical analysis and molecular survey (PCR) was done to identify the genus and species of bacteria. The results showed clinical signs including: lethargy, reduce of appetite, motionless, up-down swimming, also, in necropsy symptoms such as hyperemia and hemorrhage in external and internal organs, petechial hemorrhage and congestion in the liver, spleen and gills was observed. After culture, biochemical tests and by molecular study on 20 gram-positive isolates, 18 isolates were identified as Staphylococcus aureus that had the expected 270 bp fragment. Antibiotic susceptibility testing on isolates showed more sensitivity to Florfenicel. The following, after taking 10 mg per kilogram of the drug orally for 14 days, mortality completely stop and disease was control. The results indicate the occurrence of a severe toxemia in Siberian sturgeon have been caused by S. aureus. According to our knowledge, this is first report of isolation and identification of S. areuse from A. baeri.

In present study, Analytical Hierarchy Process method was used for determining most important traits in the breeding program of Caspian Sea trout and two questionnaires were prepared in two stages. The first questionnaire was sent to the 43 Caspian Sea trout farms that were previously identified. In this questionnaire, farmers based on their knowledge and experience were asked to select and rank the six most preferred out of 15 economic traits that they should be included in genetic improvement of this species in the breeding objectives with the aim of making more profit on their aquaculture. In this phase, 26 completed questionnaires were received. Six selective traits for compiling second questionnaire were determined as: Thermal growth coefficient (TGC), Feed Conversion Ratio (FCR), Late maturation, Survival at harvest, Fillet percentage and Flesh color (redness). According to analytical instruction, 15 pairwise comparison questions were constructed which genetic parameters based on previous studies. The second questionnaire was sent to 26 farmers who had completed the first questionnaire. Finally, 21 farmers (81%)completed pairwise comparisons. The Analytical Hierarchy Process was used to estimate the vector of individual preference values and Inconsistency Ratio using Super Decisions software. A judgment is commonly reliable when Inconsistency Ratio is less than 0. 10. After modification of the matrix of 19 observation that have Inconsistency Ratio<0. 1, the final ranged from 0. 107 to 0. 027. The median of the preferences obtained from AHP showed in both cases, before and after correction of Inconsistency Ratio, the highest preferences of genetic improvement were for survival (0. 252, 0. 191) and FCR (0. 201, 0. 275). Late maturation (0. 152, 0. 142) was third in both cases. Also, after correction of the matrixes, TGC (0. 112, 0. 133) was fourth and the percentage of fillets (0. 132, 0. 094) and Flesh redness (0. 073, 0. 057) were in the end of ranking. The results of present research can be used in the national breeding program of the Caspian Sea trout as a unique endemic species for development of aquaculture industries.

This survey was carried out on the diversity and structure of zooplankton and fish during to summer 2015 to spring 2016 in the lake of Azad dam in Sanandaj, Iran. The sampling of fish was done by gill net and Electrofishing method was also used for sampling of the Cumasi River with a current of 1. 7 amps and 100-300volts. Zooplankton sampling was carried out at 5 stations seasonally by 50 micron plankton net with a diameter of 36 cm. In the present study, 23 species of zooplankton were identified, 20 species belong to the holoplankton and 3 species belong to meroplankton groups. The results showed that the zooplankton population was 3276 ind. /m3 in the autumn, which was lower than in other seasons. In winter, the density increased and peaked in the spring. In all seasons, the rotifera accounted the highest density were of zooplankton was observed. The highest density at stations 5, 4, 2, 3 and 1, respectively. In this study 12 species of fish were identified, 11 species of the Cyprinidae and 1 species of the Nemacheilidae. The Alburnus sellal, Capoeta trutta and Carassius auratus were present in all seasons in dam and rivers. In summer, the density of the fish was 258 specimens, falling in the fall and reaching 47 specimens in the winter. From the spring, a high increasing (448 specimens) was observed in the catch, which 353 specimens belonged to the species Alburnus sellal that contained 79% of the fish caught in this season. Considering that the reservoir volume of the dam is 300 million cubic meters, there are on average about 39 tons of zoplankton in the reservoir, which is available aquatic animals of dam, especially larvae, fingerlings and fish. Considering the state of zooplankton in terms of the amount of food for fish and larvae, the dam can be used for fishery exploitation and proper management.

Climate change means any distinct change in patterns expected for climate which occurs in a long term and a particular region or the entire global climate. Increasing greenhouse gases in the atmosphere will keep the sun warm and increase the Earth's temperature. Therefore, recognizing greenhouse gas sources plays an important role in controlling adverse climate change conditions. Aquatic environments are important sources of greenhouse gas emissions, such as carbon dioxide, methane and nitrous oxide. The global warming increases the emission of methane gas from sea bottom to the atmosphere. Another event in aquatic environments related to climate change, is the attaching/adhering of biofouling species on the body of boats and ships which is followed by the high frictional resistance, due to generated roughness, which leads to an increase of weight and subsequent potential speed reduction and it may also entail a need for heavier and less energetically efficient machinery. The increase in fuel consumption can be up to 40% and produce more carbon dioxide. In rice fields (rice combined with fish), fish perturbation of the soil entails water turbidity due to resuspension of sediment granules and a higher level of methane gas emission. Thus, the purpose of this research is to briefly review the role of aquatic environments and their components, in increasing and reducing some greenhouse gases, as well as sources of these gases water ecosystems with emphases on climate change effects on the Caspian Sea based on various researches.