Recent Submissions

  • Effect of enriched rotifer (Brachionus plicatilis) with probiotic lactobacilli on growth, survival and resistance indicators of western white shrimp (Litopenaeus vannamei) larvae

    Najmi, N.; Yahyavi, M.; Haghshenas, A. (2018)
    Iranian Journal of Fisheries Sciences
    This study examined the effects of a commercial Lactobacillus probiotic on growth, survival and resistance of western white shrimp (Litopenaeus vannamei) larvae against salinity and formalin stresses in the Persian Gulf and Oman Sea Ecology Research Center. In this experiment, larvae were fed 6 times a day from mysis I (M1) step to post larvae 5 over 3 treatments including a control treatment C (without probiotic) and 2 experimental treatments namely A (having probiotic enriched rotifer) and B (having probiotic enriched rotifer and adding probiotic powder directly to the water). Larvae were stocked in 9 plastic tanks (20-liter) containing 10 L of seawater at a density of 50 larvae per liter. Three replicates were used for each treatment. At the end of the experimental period biometric larvae were studied under salinity and formalin stresses. Results showed that using probiotic bacteria had significant and positive effects on shrimp resistance, survival and growth (p<0.05) and that growth and survival rate of larvae fed with A and B treatments were significantly higher than that of the control group (p<0.05). The results of the stress tests also indicated that probiotic containing treatments (A and B) had significantly higher survival rates in salinity and formalin stresses than the control treatment (p<0.05). The highest survival rate and resistance were observed in treatment B which was not statistically different from that of treatment A (p>0.05). According to the results we may conclude that the use of probiotic powder is effective in increasing growth, survival and resistance rate of western white shrimp in the larval and post larval stages.
  • Growth performance and digestive enzymes activities of Pacific white leg shrimp (Litopenaeus vannamei) juveniles fed dietary mixtures of four medicinal plants

    Akbary, P.; Shoghi, M.; Fereidouni, M.S. (2017)
    Iranian Journal of Fisheries Sciences
    In present study the effect of dietary inclusion of equal amounts of four traditional medicines; Matricaria chamomilla L, Zataria multiflora L, Mentha piperita L and Terminalia chebulo L on growth performance and digestive enzymes activity in Litopenaeus vannamei was investigated. Two diets, including a control basal diet and an experimental diet with 30 g kg^-1 herbal mixture supplementation were prepared. Juveniles (with average weight of 2.63±0.11 g) were fed control and supplemented diet for 60 days. At the end of the experiment, shrimp fed the experimental diet showed significant increase in SGR, WGR, compared with those of the control group. Shrimp fed with herbal mixture supplementation revealed significantly higher lipase, protease and amylase activities as compared with the control group in 60 days. The results indicated that using equal mixtures of four medicinal plants in L. vannamei diets can improve the growth parameters and digestive enzyme activities.
  • Egg production and larval rearing of orange-spotted grouper (Epinephelus coioides) using reared broodstocks in Hormozgan Province, Iran

    Fourooghifard, H.; Matinfar, A.; Abdolalian, E.; Moezzi, M.; Roohani Ghadikolaee, K.; Kamali, E.; Allen, S.; Zahedi, M.R. (2017)
    Iranian Journal of Fisheries Sciences
    Egg production of cultivated broodstocks of orange-spotted grouper, Epinephelus coioides and larvae rearing were surveyed in Iran from 2008 to 2012. Broodstocks were obtained by rearing of 7 wild juveniles (587.57 ± 132.63 g body weight) which were caught from the north of Persian Gulf in October 2008 and reared to December 2012. Captured juvenile fishes were fed using defrosted trash fish at a rate of 4-6 percent of body weight per day. Four-year-old fishes spawned spontaneously, when average weight of females and males were about 7020 ± 1277 g and 5128 ± 253g respectively. Effects of four temperature ranges (23-24, 26-27, 28-29 and 31-32 °C) and three tank size ( 40L, 300L and 2400L) on hatching and survival rates were examined. Eggs were stocked as a density of 25 Eggs L^-1. Effects of tank size on hatching rate and survival of larvae were assessed at 1, 5, 10, 20 and 30 days after hatching (DAH). The optimal temperature range for hatching was 28-29°C. No difference was observed among hatching rates of fish within the various tank sizes. Survival rates of larvae in 2400L fiber glass tanks until 30 days after hatching were significantly higher than the other tanks. Results indicate this species can be reproduced and reared in large numbers under normal rearing conditions and carefully controlled temperature.
  • Effect of copper sulfate on eradication of snail’s specie [sic], Oncomelania quadrasi, in aquatic habitats having Labeo rohita as a selected fish

    Kashifa Naghma, W.; Zehra, K.; Nasir, H.N.; Imtiaz, B.; Sikender, H. (2017)
    Iranian Journal of Fisheries Sciences
    The snail species, Oncomelania quadrasi, is found abundantly in fresh water fish ponds of Punjab. It is an intermediate carrier / host of various digenetic trematode parasites which causes many serious fish diseases in aquaculture ponds. The purpose of this study was targeted for controlling these snails in aquatic environments through chemical control strategies using copper sulfate as an eradicant. Mainly three trials were conducted to determine the effectiveness of copper sulfate against this snail sp. in laboratory aquaria conditions. Trial I involved the copper sulfate treatment sprayed directly for reductions of snails present on the upper moist layer of soil. Trial II was demonstrated for reductions of the snail densities buried under the depth of 8-16 inch layer of soil. Trial III was managed to study the copper sulfate toxicity on the survival of snails and Labeo rohita present together in the same aquatic media. The study indicated that copper sulfate was effective for eradication of the snails in all conditions whether present on the wet edges / moist soil surfaces, buried in the soils or present in the aquatic environment with fish, however, with varying degrees and intensities.
  • The comparative effects of dietary supplementation with Pediococcus acidilactici and Enterococcus faecium on feed utilization, various health-related characteristics and yersiniosis in rainbow trout (Oncorhynchus mykiss Walbaum, 1792)

    Abedian Amiri, A.; Azari Takami, Gh.; Afsharnasab, M.; Razavilar, V. (2017)
    Iranian Journal of Fisheries Sciences
    This study examined the effects of feeding of two dietary probiotics on growth performance and feed utilization, intestinal colonization and related health criteria, biochemical parameters, hematological indices, and immune parameters and protection against Yersinia ruckeri in Oncorhynchus mykiss during a period of 56 days. The study included 3 groups: 1) a control group of fish, 2) a group of fish fed with a basal commercial diet supplemented with 2 × 106 CFU g^-1 Pediococcus acidilactici (PA-group and 3) a group of fish fed with a basal commercial diet supplemented with 2.5 × 108 CFU g^–1 Enterococcus faecium strain IR5 (EF-group). Each group was run in triplicate. The PA-group and EF-group showed significant improvement with respect to WG, SGR, FCR, PER, lactic acid bacteria (LAB) (%) in intestinal, intestinal colonization (log CFU g^–1), survival (%), RBCs, WBCs, hematocrit percentage (Hct %), and respiratory burst activity (RBA) levels, each of which was significantly higher than that in the control group (p<0.05). The WG and PER in the EF-group were significantly higher than that in the PA and control groups (p<0.05). Levels of immune-system response across a variety of measures, some of the measured hematological indices, LAB (%) in intestines, and survival rate (%) were higher in the PA group than that in the EF group on 56th days of feeding. Mortality in the PA group (20%) and EF group (33.3%) were significantly lower compared with that in the positive control (73.3%) during the 10 days following exposure to Y. ruckeri (p<0.05).
  • Safety evaluation of chloramine-T on ornamental zebra fish (Danio rerio) using LC50 calculation and organ pathology

    Alidadi Soleimani, T.; Sattari, A.; Kheirandish, R.; Sharifpour, I. (2017)
    Iranian Journal of Fisheries Sciences
    The need of aquarists for proper and safe disinfection of fish with Chloramine-T (CL-T) necessitates toxico/pathologic examinations. This study assays toxicity level of CL-T and histopathologic changes of gills, liver, kidney and brain of treated zebrafish (Danio rerio). Groups of 10 Zebrafish were treated with 0 (control), 5, 10, 15, 30, 50, 100 and 200 mg/L of CL-T. Mortality was recorded at every 6 hours until 96h after the beginning of the treatment and lethal concentration for 50% of population (LC50 at 24h and 96h) was calculated. The histopathologic samples were taken from dying fish during the exposure period. Histopathological changes were not evident in organs of the control group. In the gills of treatment groups, congestion, edema, separation of epithelium of secondary lamella from basal membrane, fusion and hypertrophy of secondary lamella, telangiectasis and necrosis of lamella epithelium were observed. In the liver of treatment groups degenerative changes and necrosis of hepatocytes were visible. The kidney samples represented hydropic degeneration, necrosis, dilation of periglomerular urinary space and hyaline droplets in renal tubules in high concentration. The brain of treatment groups showed spongiosis and increase in glial cells. Severity of these lesions was related to the concentration of CL-T. LC50 24h for CL-T was 428.649 mg/L and LC50 96h was 11.044 mg/L which reveals the low level of toxicity for few hours of treatment. The concentrations below 15mg/L are reasonably safe and recommended for usage in D. rerio treatment during 24h of bath.
  • Effects of stocking density, feeding technique and vitamin C supplementation on the habituation on dry feed of pikeperch (Sander lucioperca) pond reared juveniles

    Ljubobratovic, U.; Kucska, B.; Sandor, Z.; Peteri, A.; Ronyai, A. (2016)
    Iranian Journal of Fisheries Sciences
    Influence of three different stocking densities, vitamin C supplementation of Daphnia spp. and feeding practice (i.e. mechanical, hand) on the success of dry feed habituation of pond reared pikeperch juveniles was investigated through one month trial. Pond reared pikeperch juveniles were harvested 42 days post-fertilisation (mean individual weight 1.1 ± 0.3g) and stocked into the experimental recirculation system. For the stocking density trial, fish were stocked in three different initial densities of 0.5, 1 and 1.5 fish L^-1, while the trial on live food supplementation and feeding practice was performed with two two-group comparisons with one common control treatment. All treatments were performed in 3 replicates. Analysis of variance did not reveal any significant differences in the assessed parameters between the tested stocking densities. However, Pearson correlation for the habituation success was strong in the course of increased density (r^2 = 0.829, p = 0.006). Vitamin C supplementation led to increased survival, habituation success and growth, although the differences were not significant (p > 0.05). Similarly, there were no significant differences between the hand and mechanical feeding in the habituation success (p = 0.860). Based on the results of present study and previous results reported for habituation of pikeperch and walleye pond nursed juveniles, stocking densities of 4 to 8 fish L^-1, feeding with dry feed with worms supplied manually and possible enrichment with vitamin C of the given food could be suggested for the successful commercial pikeperch dry feed habituation.
  • Determination and study the fatty acid contents and their seasonal variations by temperature of a dominant bivalve (Callista umbonella) of Haleh Creek

    Sajjadi, N.; Mooraki, N. (2016)
    Iranian Journal of Fisheries Sciences
    In this study fatty acid contents, because of the importance in human’s life, and their seasonal variations of a dominant bivalve of Haleh Creek were determined for the first time. Fatty acid identification was done by GC-MS (Gas Chromatography–Mass Spectrometry) method. After collecting and dissecting the species from the shells, samples were weighed and frozen for further experiments. All the samples esterified and made ready for injection to the GC-MS. Temperature as an important environmental parameter monitored monthly, variability of the fatty acid components studied in two seasons, and the effect of temperature changes on seasonal variations of the fatty acids were studied by statistical analysis. In conclusion sixteen fatty acids were identified in Callista umbonella, including twelve saturated and four unsaturated, which the most important were oleic, palmitic, myristic, hexadecanoic and nonadecanoic acids while saturated fatty acids were dominated over unsaturated ones. The most abundant saturated fatty acid was palmitic acid and unsaturated one was oleic acid in this species. Although fatty acids’ seasonal changes did not show any significant difference and also any significant correlation with temperature in the species in this area, but in general fatty acid amounts might be vary in different temperatures and it could be related to many environmental and biological factors in species.
  • Species diversity and distribution pattern of marine mammals of the Persian Gulf and Gulf of Oman - Iranian Waters

    Owfi, F.; Braulik, G.T.; Rabbaniha, M. (2016)
    Iranian Journal of Fisheries Sciences
    A total of 98 marine mammal records from Iranian coastal waters of the Persian Gulf and Gulf of Oman were compiled of which 66 are previously unpublished new records. Seventy-nine were from the Persian Gulf and 16 from the Gulf of Oman coast. The largest numbers of records were from Qeshm Island and Bushehr Provinces. Records of finless porpoise (Neophocaena phocaenoides), Indo-Pacific humpback dolphin (Sousa chinensis) and Indo-Pacific bottlenose dolphin (Tursiops aduncus) were by far the most numerous probably reflecting their inshore distribution and local abundance. Other species recorded are common dolphin (Delphinus capensis tropicalis), rough-toothed dolphin (Steno bredanensis), Risso’s dolphin (Grampus griseus), false killer whale (Pseudorca crassidens), and dugong (Dugong dugon). Evidence of 22 Mysticetes were obtained eight of which were tentatively identified as Bryde’s whales (Balaenoptera edeni), three as fin whales (Balaenoptera physalus) and three as humpback whales (Megaptera novaeangliae). The largest threat to marine mammals in Iran is likely to be incidental capture in fishing gear. Six by-caught finless porpoises were recorded, and this species may be particularly vulnerable to incidental mortality in gillnets. Recommended marine mammal research, conservation and management small projects in Iran are described.
  • Effects of stocking density on growth performance and survival of three male morphotypes in all-male culture of Macrobrachium rosenbergii (De Man)

    Banu, M.R.; Christianus, A.; Siraj, S.S.; Ikhsan, N.F.M.; Rajaee, A.H. (2016)
    Iranian Journal of Fisheries Sciences
    A study was conducted to appraise the effect of different stocking densities on three male morphotypes named blue claw (BC), orange claw (OC) and small male (SM) at harvest in all-male culture and to assess the growth performance of BC, OC and SM in each isolated culture. Trials involving three stocking densities of all-male prawn viz., 20, 30 and 40 juvenile m^-2 were carried out in replicates. After 4 months of culture, BC, OC and SM were sorted from all tanks and restocked at 5 m^-2 in treatments BC, OC and SM respectively for 80 days. A difference in prawn density significantly (p<0.05) affected adversely on morphotypes. The highest survival rate combined with good yield performance was from 20 juvenile m^-2 stocking density with 21% BC, 62.5% OC and 16.5% SM, respectively. In isolation culture, the average specific growth rate of the SM population (1.22) was significantly higher than that of the OC (1.01) and the BC (0.43) population. The survival of the SM population was 100% while for others it was 72%. Absolute weight of prawn was significantly greater in the male OC (23.87 g) than the SM (19.57 g) and the BC males (6.31 g). Impacts of isolated culture on population structure were much more pronounced in the SM population than others.
  • Effects of dietary isoflavone-genistein on hematological and immunological parameters in pre-brood stock beluga, Huso huso

    Bahmani, M.; Ghasemi, R.; Yousefi Jourdehi, A. (2016)
    Iranian Journal of Fisheries Sciences
    This study was carried out with the aim of detecting the dietary effects of isoflavone-genistein on hematological and immunological parameters in beluga, Huso huso in a 12-week feeding period. Five isonitrogenous (45% crude protein) and isoenergetic (19.5 MJ kg^-1) diets were formulated to contain four graded levels of isoflavone-genistein, namely 0, 0.2, 0.4, 0.8 and 1.6 g kg^-1 diet. Fish (initial average weight: 26.1 ± 1.8 kg) were stocked in ponds in groups of 3 and fed the experimental diets in triplicate. At the end of experiment, physiological indicators, including hematological and immunological parameters, such as red blood cell (RBC), white blood cell count (WBC), hematocrit (Ht), hemoglobin (Hb), lymphocyte, neutrophil, eosinophil, monocyte, haematological indices, lysozyme, total immunoglobulin (IgM) and complementary activities were determined. Results suggested that mean corpuscular hemoglobin concentration (MCHC) and values of neutrophil had significant differences between treatments. The activities of serum lysozyme, IgM, C3 and C4 were significantly influenced by the dietary genistein concentrations. Results indicated that genistein had significant effects on some hematological and immunological parameters in beluga.
  • The effect of created hemolymph apoptosis on WSSV Gamma-vaccinated shrimp, Litopenaeus vannamei in WSSV disease control

    Kakoolaki, S.; Afsharnasab, M.; Sharifpour, I.; Ghaednia, B. (2016)
    Iranian Journal of Fisheries Sciences
    White spot syndrome virus (WSSV) is the causative agent responsible for huge-shrimp viral epidemics in shrimp farms throughout the world. Our study was aimed to determine the effect of WSSV Gamma-vaccinated Litopenaeus vannamei on the occurrence of apoptosis. One thousand and twenty PL15 were randomly distributed among 2 treatments and two control groups. Gamma-Vaccinated shrimp and non-Gamma-vaccinated ones were our treated and untreated groups. Based on our results significant differences (p<0.05) were observed in survival percent between vaccinated-exposed group (82.33±2.51) and non-vaccinated exposed group (26.00±10.00). It is concluded that apoptosis can be a helpful process in enhancing the immune response in shrimp especially against WSSV.
  • Effects of supplementation of algae (Sargassum ilicifolium) on growth, survival and body composition of rainbow trout Oncorhynchus mykiss

    Zamannejad, N.; Emadi, H.; Hafezieh, M. (2016)
    Iranian Journal of Fisheries Sciences
    The effects of substituting dietary protein sources with different levels of Sargassum ilicifolium on growth, survival and body composition of rainbow trout Oncorhynchus mykiss were investigated over the course of a 60 day experiment. A total of 360 juveniles (75±2.8 g) were randomly allotted to four treatment groups including control: with 100% basal diet (BD); T1: 5% sargassum meal (SM)+95% BD; T2: 7.5% (SM)+92.5% BD and T3: 10% (SM)+90% BD. Each treatment group was divided into three replicates of 30 fish per replicate. At the end of the experiment, our results showed that replacement of 5% and 7.5 % of basal diet with sargassum meal showed significant differences in average weight and total length, feed conversion ratio (FCR), specific growth rate (SGR), weight gain percent (WG), condition factor (CF) and survival rate (SR). There were significant differences between calorie content of carcass in T2 and control with T1 and T3 (p<0.05). The highest values of carcass protein content were observed in T1 (p<0.05). There were significant differences between lipid content of fish in T2 and control with that of fish in T1 and T3 (p<0.05). The highest values of carcass ash content were observed in T1, (p<0.05) which were not significantly different from that in other treatments (p>0.05). Levels all of amino acids were higher in fish in T2.
  • Digestive alkaline proteases from the Tunisian barbel (Barbus callensis): Characterization and application as a detergent additive, in chicken feather-degradation and as a dehairing agent

    Sila, A.; Haddar, A.; Sayari, N.; Nasri, M.; Bougatef, A. (2015)
    Iranian Journal of Fisheries Sciences
    Alkaline crude enzymes from the viscera of the Tunisian barbel (Barbus callensis) were extracted and characterized. Proteolytic crude extract from barbel viscera was active and stable in alkaline solution. The optimum pH and temperature were 11.0 and 55 °C, respectively, using casein as a substrate. The crude alkaline protease was extremely stable in the pH range of 5.0-12.0. Zymography activity staining using casein as a substrate showed the presence of at least five distinct proteases. The crude alkaline proteases showed stability towards various surfactants, bleach agents and compatibility with some commercial detergents. Alkaline proteases from the viscera of the barbel were tested in chicken feather-degradation and showed important feather degrading activity. Complete solubilisation of whole feathers was observed after 24h of incubation at 50°C. Additionally, crude alkaline protease demonstrated powerful capabilities of hair removal from skin and the collagen, the major leather-forming protein, was not significantly degraded. Considering its promising properties, alkaline crude enzyme from the viscera of the Tunisian barbel may be considered as a potential candidate for future use in several biotechnological processes.
  • Compensatory growth, proximate composition and amino acid contents after experiencing cycles of feed deprivation and re-feeding in young yellow catfish (Pelteobagrus fulvidraco R.)

    Ruan, G.; Wan, Q.; Yao, F.; Yang, Y.; Zhang, J.; Huang, L. (2015)
    Iranian Journal of Fisheries Sciences
    The compensatory growth, proximate composition and amino acid contents changes of young yellow catfish (Pelteobagrus fulvidraco R.) (1.63-1.69 g) had been investigated using a 45-day cyclic feed deprivation and re-feeding experiment. The control group (S0) was fed daily with live tubificid worms (Limnodrilus hoffmeisteri), while the S1/4, S1/2, and S1/1 groups cyclically experienced one-day of feed deprivation followed by four, two or one day(s) of feeding, respectively. Over- or full-compensatory growth was achieved in the cyclic deprivation/re-feeding groups through increased feeding rate (FR) and feed conversion efficiency (FCE). However, the fish behaved different courses of growth compensation, the compensatory growth responses of fish subjected to a weaker intensity of feed deprivation (i.e., S1/4) compared with more intense deprivation (i.e., S1/1) was achieved in these groups mainly by a gradual increases in FR or by maintaining a high FCE, respectively. The cyclic deprivation/re-feeding schedules did not affect the proximate composition of the fish body, however, the amino acid parameters were inversely related to the specific growth rate, the fish showing growth over-compensation contained significantly lower contents of total amino acids, essential and non-essential amino acids.
  • Isolation and identification of halophilic bacteria from Urmia Lake in Iran

    Irannejad, S.; Akhavan Sepahi, A.; Amoozegar, M.A.; Tukmechi, A.; Motallebi Moghanjoghi, A.A. (2015)
    Iranian Journal of Fisheries Sciences
    Halophiles are in all three domains of life: Archaea, Bacteria and Eucarya. Halophilic microorganisms in addition to forming a major part of life biodiversity can have many biotechnological applications. The objective of this research is isolation and identification of halophilic bacteria from Urmia Lake in Iran and the study of its bacterial biodiversity. After sampling of brines from Urmia Lake from 10 stations and depth of approximately 30-50 cm, in April 2011 and transfer to the laboratory in the sterile conditions, samples were enriched and cultured on defined media, and incubated. After appearance of colonies, selected strains were studied based on morphology, physiology and biochemical characteristics. For phylogenetic identification, their genomic DNA were extracted and amplified by PCR technique. Therefore their sequences were determined by genetic experiment based on 16S rRNA gene sequence and their similarity were analysed in GenBank of EzTaxon database. Finally the phylogenetic tree was constructed. Studied strains belonged to three genera: Halomonas 50% (including H. andesensis LC6(T) [12.5%], H. gomseomensis M12(T) [12.5%], H. hydrothermalis Slthf2(T) [12.5%], H. boliviensis LC1(T) [6.25%] and H. janggokensis M24(T) [6.25%]), Salinivibrio 25% (including S. costicola subsp. alcaliphilus DSM 16359(T) [18.75%] and S. sharmensis BAG(T) [6.25%]) and Idiomarina 25% (including I. loihiensis L2TR(T) [25%]).
  • Full replacement of fishmeal by poultry by-product meal in rainbow trout, Oncorhynchus mykiss (Walbaum, 1972) diet

    Keramat Amirkolaie, A.; Shahsavari, M.; Hedayatyfard, M. (2014)
    Iranian Journal of Fisheries Sciences
    Along the plant ingredients, rendered animal protein sources such as blood meal, meat and bone meal and poultry by-product meal have potential to be replaced by fishmeal in rainbow trout feed. Therefore, the main objective of the present study is to determine the effect of full replacement of fishmeal by poultry by-products meal (PBM) on fish performance, nutrient digestibility and also liver characteristics in rainbow trout. Four experimental diets were formulated to contain graded levels of PBM at 0 (control diet), 33 (PBM33), 66 (PBM66) or 100% (PBM100), respectively. The four treatments were randomly assigned to each of 12 tanks, having three replicates for each treatment. Rainbow trout juveniles with an average initial weight of 50±0.42g were reared for two months. The fish gained lower weight and specific growth rate at PBM 66% and 100%. FCR was recorded larger for rainbow trout feeding on PBM 66% and 100% in comparison to PBM 33% and control diets (p<0.05). The whole exchange of fishmeal by PBM (PBM100%) reduced dry matter, fat and protein digestibility (p<0.05). An increase in PBM content of diet also resulted in larger fat content of the fish liver (p<0.05). Body fat content reduced and moisture content increased by increasing PBM level (p<0.05). In conclusion, PBM can be included in rainbow trout feed as an alternative for fishmeal up to 33%. A larger fat content of liver at PBM 100% may indicate a negative impact of PBM on rainbow trout health at full replacement level.
  • The effects of mate switching tacticon reproductive performance of the severum cichlid, Heros severus

    Hedayati Rad, M.; Forsatkar, M.N.; Huang, W.B. (2014)
    Iranian Journal of Fisheries Sciences
    This study investigated the effects of mate switching on the reproductive performance of the severum cichlid, Heros severus, by advancing the egg and larval production in hatcheries. Two reproductive tactic treatments of “monogamous pair” and “mate switching” were used for evaluating 4 reproductive traits of egg production, hatching rate, spawning intervals, and starvation tolerance of the larvae in 6 spawning activities. The number of eggs was not significantly different between the two reproductive tactic treatments in the 6 spawning activities, but the spawning intervals, hatching rate, and survival activity index were all significantly different. Daily average egg and larval production in the mate switching treatment were estimated to be 87.3 eggs and 43.1 larvae per pair of fish, respectively, which was 2.89 times and 1.99 times of those in the monogamous pair treatment, who produced about 30.2 eggs and 21.6 larvae per pair. Our results clearly showed that the reproductive tactic of mate switching is a suitable method for increasing the egg and larval production rate of the severum cichlid.
  • Proximate and fatty acid composition of liver and fatty tissue of patin catfish (Pangasianodon hypophthalmus)

    Shabani Kakroodi, S.; Christianus, A.; Tan, C.P.; Che Man, Y.B.; Ehteshami, F. (2014)
    Iranian Journal of Fisheries Sciences
    The visceral storage fat and liver of patin catfish (Pangasianodon hypophthalmus) are normally discarded, which incurs cost and can cause environmental pollution. However, these may be potential sources to extract fish oil. The proximate and fatty acid compositions of liver and fatty tissue of patin catfish were investigated to evaluate the suitability of these by-products for extracting fish oil. Fat was extracted using a low temperature solvent extraction method. The average fat content of fatty tissue and liver of females were 77.64 and 11.71%, respectively, whereas in males this was 73.23 and 9.59%, respectively. Fatty acids found in the extracted oil of these byproducts were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6. The major fatty acids presented in these tissues were palmitic (C16:0), oleic (C18:1 n-9), and linoleic acid (C18:2 n-6). The total amount of polyunsaturated fatty acids of liver from male and female patin catfish were 13.31 and 13.30%, respectively, whereas in the fatty tissue these were 11.64 and 12.09%, respectively. The n-3 to n-6 ratios of liver and fatty tissue of females were 1.61 and 0.95, respectively, whereas in male fish these were 1.31 and 1.05, respectively. Results of this study indicated that the liver and fatty tissues of patin catfish are suitable sources of fish oil specifically due to the presence of monounsaturated and n-3 polyunsaturated fatty acids.
  • A comparison on FCR in fish ponds of rainbow trout (Oncorhynchus mykiss) fed by extruder food and pellet food

    Pirali Kheyrabadi, E.; Salehi Farsani, A.; Samadi Kuchaksaraei, B. (2014)
    Iranian Journal of Fisheries Sciences
    Food costs in rainbow trout farms are about 50% of production costs (Barrows et al., 2007). Because of inattention of most aquaculturists in exact calculation of FCR and not using qualified food, sometimes food costs will rise a lot and won't be economical. The newest method for fish food production is production during the process of extrusion. Extrusion process is processing materials with high temperature in a short time (HTST) and is done by combined operation of humidity, heat, mechanical energy and pressure (Watanabe and Pongmaneerat, 1993).

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