64 research outputs found

    The status of white spot syndrome virus (WSSV) in Islamic Republic of Iran

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    White spot syndrome virus (WSSV), the causative virus of disease, is found in most shrimp farming areas in Iran, and it causes large economic losses to the shrimp farming industry. Shrimp aquaculture is an important industry in Iran and plays an important role in aquaculture production. The shrimp production in 2012 was more than 12000 metric tonnes and it is estimated it will reach 20000 tonnes in 2013. White spot syndrome virus is highly virulent in shrimp farms and can spread quickly and cause up to 100% mortality within 3-7 days. The virus is a very large, enveloped, double stranded DNA (ds DNA) and assigned by ICTV to a new genus Whispovirus and belong to Nimaviridae family. In Iran WSSV first appeared in Khuzestan Province in the south of Iran, and later on it appeared in other provinces such as Bushehr, and Sistan and Baluchestan. The aim of this review is to give current information of WSSV in Iran, host ranges, carriers, biology, clinical signs, histopathology, PCR, with emphasis on the effects of WSSV in shrimp aquaculture

    Factors affecting the policyholders' satisfaction <of> coldwater fish farmers of Mazandaran Province using agricultural insurance

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    The goal of this research was considering the reasons of policy holder satisfaction of breeding freshwater fish farms with agriculture insurance in Mazandaran province. The population of this research was the number of 63 freshwater fish breeders in Mazandaran province had assured their farms through Agricultural Insurance Fund during years 88 to 92 and they have utilized questionnaires for field data collection, its validity was approved by experts’ panel and its reliability was approved through utilization of Cronbach’s alpha coefficient (0.85). the variable " Agricultural Insurance Fund has considered on our complain on time" had more sound on satisfaction at the level of %30 followed by the variable " I am satisfied with specification and estimating damage of agricultural insurance" with the level of %28 and" the distance between damage and the time of compensation assessment by Insurance Fund is suitable " in level of %23 and" mangers and personnel attitude of Agricultural Insurance Fund is suitable" in level %20 are effective in measure of satisfaction. Obtained results from the research indicate that the main dissatisfaction of breeders had been about "becoming time-consuming between damage and compensation payment, being unsuitable and defective of specification and estimating compensation process, the way of considering on complain and demand of breeders and the way of managers and personnel of Agricultural Insurance Fund attitude and behavior

    The effects of brown algae Sargassum angustifolium extract on growth performance, survival and Vibriosis resistance in shrimp Litopenaeus vannamei

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    In this study, the effect of ethanolic extracts of Sargassum angustifolium on growth and survival of shrimp Litopenaeus vannamei juvenile was investigated under challenge with shrimp pathogen bacteria Vibrio harveyi. Powder form of the extract was bioencapsulated in Artemia and fed to L. vannamei juvenile reared as 5 groups inclouding C- (unenriched Artemia, without bacteria), C+ (unenriched Artemia, with bacteria), T1 (enriched Artemia with 200 mg l-1 SA extract, with bacteria), T2 (enriched Artemia with 400 mg l-1 SA extract, with bacteria), T3 (enriched Artemia with 600 mg l-1 SA extract, with bacteria). One week after culture all groups except C- were inoculated with V. harveyi at the rate of 1.5 × 108 CFU ml-1 for 15 minutes then after every water exchange 10 ml of V. harveyi at the rate of 1.5 × 107 CFU ml-1 was added to aquaria. Shrimps at group C- showed maximum survival (86.6%), specific growth rate (SGR, 11.33%) and less bacterial load (0.5 ± 0.03× 102 CFU g-1 tissue). While (C2) exhibited lowest survival (33.3%), SGR (9.90%) and more bacterial load (3.4 ± 0.05× 105 CFU g-1 tissue) and the difference was significant (p<0.05). In treatment groups survival and SGR were significantly (p< 0.05) more than C+ and less than C-, also bacterial load were less than C+ and more than C-. Among treatment groups T2 that fed with enriched artemia with 400 mg l-1 SA extract gave better results than the other treatments

    The effect of created hemolymph apoptosis on WSSV Gamma-vaccinated shrimp, Litopenaeus vannamei in WSSV disease control

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    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

    Chemical, microbiological and sensory evaluation of gutted kilka coated with whey protein based edible film incorporated with sodium alginate during frozen storage

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    The effects of whey protein (12%) and sodium alginate (0.5%) on chemical, microbial and sensory changes and shelf life in kilka during frozen storage are investigated for up to 6 months. Total bacteria count and Staphylococcus bacteria counts(2 / 51 and 1 / 44 log CFU/g) in coated samples showed decrease in comparison with control samples(3.21- 2.28 log CFU/g). Moisture of coated samples had significant increase than control treatment (p<0.05). Protein, lipid, ash and calorie were higher in test samples as compared with the control samples. Free fatty acids, TBRS, peroxide value, TVN and pH in coated samples showed significant decrease in comparison with control (p<0.05). Sensory evaluation of coated samples showed significant difference in comparison with control (p<0.05). It is suggested that whey protein edible coating incorporated with sodium alginate can enhance quality and increase shelf life of kilka fish in storage of freezing up to 6 months

    Selected morpho-chemical features of hemocytes in farmed shrimp, Fenneropenaeus indicus in Iran

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    The aim of the present study was to determine various types of hemocytes, total and differential hemocyte count and to show some indices of phagocytosis, including percent phagocytosis and phagocytic index in Indian white shrimp, Fenneropenaeus indicus in Iranian shrimp farms. The hemolymph was extracted from the shrimps and mixed with anticoagulant. It then stained and Yeast was added as foreign particles to samples. Based on the cell size and presence of the granules and nucleocytoplasmic ratio, three major groups of hemocytes, including hyaline cells, small granular cells (SGC) and large granular cells (LGC) were identified. Hyaline cell (HC) was the smallest hemocyte. HC (hyaline cell) about was 10-15%, lower quantity in comparison to some species and those of LGC and SGC were 20-25% and 60-65%, respectively, suggesting that relative percentage of differential hemocyte count in Fenneropenaeus indicus is different from other decapods. Also, in this study, it was shown that SGH and LGH could engulf the yeast particles. In Contrast to some previous studies, no engulfment was observed by hyaline cells in vitro. In this study it was showed that there are some variations in total and differential hemocyte count compare to other species in the family of Penaeidae

    Effects of Chlorella vulgaris on blood and immunological parameters of Caspian Sea salmon (Salmo trutta caspius) fry exposed to Viral Nervous Necrosis (VNN) virus

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    In the present study, the effects of Chlorella vulgaris on blood and immunological parameters of Caspian salmon (Salmo trutta caspius) before and after exposure to Viral Nervous Necrosis (VNN) virus were examined. In this regard, four treatments in triplicate were chosen. Groups included one control and 3 treatments (T1, T2 and T3). Fish in control group, T1, T2 and T3 were fed diets supplemented with 0, 1×10^8, 2×10^7 and 3×10^6 chlorella/450 g of food respectively, for sixty days. In addition, a virus supernatant was prepared from infected wild golden grey mullet (Liza auratus) and used for virus challenge of S. trutta caspius. Virus was injected intraperitoneally and blood samples were collected before and 14 days after the challenge. Immunological (IgM, C3, C4, total protein, respiratory burst, albumin and lysozyme) and changes in blood parameters (RBC, WBC, Htc, Hb, MCH, MCHC and MCV) were also measured. Results showed that C. vulgaris could act as a natural immunestimulant. Also, the alteration trend in hematological and immunological parameters showed that experimental fish could be considered to be resistant to VNN virus after exposure and fish treated with C. vulgaris were more resistant in comparison to those in the control group. The dose used in T1 (1×10^8 chlorella/450 g food) was the most effective approach with significant differences

    Evaluation of the effects of different concentrations of neutral anolyte on fungal infected eggs in rainbow trout (Oncorhynchus mykiss) in comparison with green malachite

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    The objective of this study was to determine the effect of different concentrations of anolyte on saprolegniasis in comparison with green malachite in rainbow trout hatcheries, in the northern part of Iran, Tonekabon. Nearly 5000 green eggs of Oncorhynchus mykiss (equivalent to 300 g) were obtained from a private farm in the north of Iran. The study was designed in 5 treatments, 0.25, 0.5, 30 and 100 ppm of neutral anolyte and 2 ppm of green malachite and two controls including positive control, meaning that the green eggs were purposely infected with saprolegnia but without any disinfectant, and negative control, which was implied to as the untreated group, all in triplicate. There was no significant difference (α>0.05) in hatchability percent between 2 ppm of green malachite and the group treated with 0.25 ppm of neutral anolyte, contrary to other anolyte concentrations. It is concluded that constant use of 0.25 ppm of neutral electrolyzed oxidized water (NEOW) is a more effective anti-fungal solution with the least side effects in comparison with 2 ppm of green malachite

    Immunological and histopathological changes in Penaeus semisulcatus challenged with Vibrio harveyi

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    Two-hundred and sixty five green tiger shrimp juveniles (Penaeus semisulcatus) with the average weight of 7-12g were collected from Helleh farms in Bushehr province and transported to Iran Shrimp Research Center of Bushehr in October, 2009. The juveniles were acclimated for two weeks. The experiment was designed in three treatments (named 3, 4 and 5) and two controls (named 1 and 2) in triplicate with 15 shrimp in each repetition prepared of glass aquarium. All the treatments and repetitions were exposed to Vibrio harveyi (NCBI: GU974342.1). The concentrations of the treatments were 10^8,10^6 and 10^4 CFU ml^-1 in individual containers dedicated for each mentioned treatment (3, 4 and 5, respectively). The controls prepared with no any bacteria and fully filled with chlorinated and UV treated sea water were named 1 and 2 respectively. The hemolymph were withdrawn from abdominal segments of samples for measuring THC and TPC evaluation at designed hours (2, 6, 12, 24, 48, 96, 144, 192 and 240). The shrimp samples were also fixed in Davidson fixative for histopathological studies. The results showed that the difference of THC value between controls and group 3 during 12 till 96 hours of experiment was significant (P 0.05) between group 5 and control groups of THC. The data showed that differences of TPC value between control groups during 24 to 96 hours were significant (P< 0.05), whereas the differences between controls with groups 4 and 5 during 48 to 144 hours and 192 hours, were significant (P< 0.05) respectively. TPC and THC were observed with an increase in the concentration of bacteria and passing the time as inverse bell shape procedure. In histopathology, gills showed melanization and color changed to brown and black. The hepatopancreas cells revealed necrosis and vacuolization of B, E, R and F cells. The bolitas ball and bacterial colonization was observed in the intestine. Our results showed that Vibrio harveyi with 10^8 and 10^6 cell/ml decreased immunity factors such as THC and TPC. The histopathological changes increased with increasing the concentration of bacterial level. This finding can be used for assessing the health of shrimp culture and prevention of vibriosis

    The effect of different salinities on mortality and histopathological changes of SPF imported Litopenaeus vannamei, experimentally exposed to White Spot Virus and a new differential hemocyte staining method

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    Shrimp farmers have been suffering from loss of production due to White Spot Disease (WSD) in the last decades. A few studies focused on the environmental factors predisposed WSD. Our study aimed to investigate the effects of the different salinities on occurrence of WSD. The treatments were 30 ppt, 40 ppt and 50 ppt in triplicate and corresponding untreated control groups. White Spot Virus (WSV) was intramuscularly injected to the shrimp in whole treatments. PCR and histopathological findings within the measurement of some hemolymph parameters such as Differentiated Hemocyte Count (DHC), Total Hemocyte Count (THC) and Total Plasma Protein (TPP) were carried out. A positive result was observed for the occurrence of the antigen of the WSV obtained from the samples of each treatment of salinity due to the challenging treatments with the WSV. Mortality at the salinity of 30 ppt began at 72 h post inoculation as well as the salinity of 40 ppt, but at 50 ppt it started after 50 h. The Minimum and maximum count of mortality at the salinity of 30, 40 and 50 ppt were 3.5, 8.5 0.5, 4.5 and 1.5, 7.5, respectively. No mortality was observed in the untreated control groups of 30, 40 and 50 ppt during the experiment. It is concluded that the higher and the lower salinity, lesser or greater than the normal condition in exposed to WSV could lead to severe mortality of WSD
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