The effect of ethanol extract of a macroalgae Laurencia snyderia on growth parameters and vibriosis resistance in shrimp Litopenaeus vannamei

Bacterial diseases have been reported to be the major limiting factor in shrimp production. The use of natural products such as antimicrobials has been reported as a solution to the problem. The crude extract of a red seaweed Laurencia snyderiae obtained from the Persian Gulf was evaluated for shrimp growth performance and to determine in vivo efficacy of this seaweed in the prevention of shrimp Vibriosis. The ethanol extract from L. snyderiae (EELS) that was fed to the Artemia instar I for their enrichment was found to be non toxic to them. Shrimp Litopenaeus vannamei juveniles were fed with these enriched Artemia at 0 mg mL^-1 (Control group), 200 mg mL^-1, 400 mg mL^-1 and 600 mg mL^-1 for 30 days. The results obtained showed a significant increase (p<0.05) in survival rate in treatment groups compared with that in the control group. Shrimps fed with enriched Artemia showed a significant improvement in growth parameters when compared to those in the control group. When these juvenile shrimps were exposed to Vibrio harveyi (after 30 days) they showed notably lower mortality than the control. These results indicate that EELS has a good potential in promoting growth and antibacterial activities against V. harveyi that is useful in shrimp aquaculture

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

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

Detection and identification of white spot syndrome virus (WSSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) of Litopenaus vannamei from Bushehr and Sistan and Baloochestan provinces (Iran), during 2009-2010

The first time the white spot disease (WSD) and IHHNV were reported in Iran was in 2004 and 2008, respectively in Bushehr Province. In Sistan and Balochestan province only the WSD was reported in 2008.The aim of this study was detecting these two viral diseases in these provinces, during December 2009 to April 2010. A total of 364 samples were collected according to suspected gross signs from hatcheries and shrimp farms in Bushehr and Sistan and Blochestan provinces (I.R. Iran) respectively, including larvae (72, 43 samples), post larvae (48, 37 samples), juveniles (57, 32 samples), sub adults (39, 22 samples) and broodstock (29, 13 samples) of Litopenaus vannamei . WSD was detected from juveniles (23 samples), sub adults (14 samples), and broodstock (14 samples), and IHHNV was also detected from juveniles (16 samples), sub adults (9 samples) and broodstock (5 samples) based on gross signs, PCR and histopathological changes from Bushehr province but from Sistan and Blochestan province only WSD was detected from juveniles (26 samples), sub adults (18 samples) and broodstock (7 samples). Histopathological observations of WSSV showed basophilic Cowdry type A inclusion bodies in all tissues such as gills, haematopoietic tissue, cuticle epithelium, lymphoid organ and connective tissue. However histologically, the hepatopancreas tissue showed vacuolization of B cells , without inclusion bodies, but histopatholgical changes caused IHHNV including eosinophilic Cowdry type A inclusion bodies which were ectodermal, mesodermal and rarely endodermal

Titration of the Iranian white spot virus isolate, on crayfish Astacus leptodactylus and Penaeus semisulcatus

White Spot Virus (WSV) is currently the most serious viral pathogen of shrimp worldwide; it causes mortality up to 100% within 7-10 days in commercial shrimp farms. Infected Indian white shrimp Fenneropenaeus indicus samples were collected from Guatr shrimp site in Sistan and Baluchestan province in south of Iran and WSV infection was confirmed by Nested PCR. WSV was isolated from infected shrimp samples by centrifugation and filtration and multiplied in crayfish by intramuscular inoculation, the isolated virus was called WSV/IRN/1/2010. In order to determine the dilution resulting in 90-100% mortality in Penaeus semiculcatus, diluted virus stock in steps from 10^0 till 10^5 times in sterile PBS was injected intramuscularly to 14 shrimps in each group. Also the virus stock was diluted in steps from 1/2 till 1/32 times in sterile PBS and injected intramuscularly in Astacus leptodactylus crayfish. Therefore the LD50 of live virus stock in Astacus leptodactylus and Penaeus semiculcatus crayfish were calculated by the Karber method 10^3.29 /ml and 10^5.35 /ml, respectively

Hemocytosis, a new disease in cultured shrimp, Fenneropenaeus indicus

Certain parasites can cause severe diseases in shrimp. Among these, protozoa are very important. The objective of our study was to describe the signs, prevalence, and intensity of hemocytosis, a new disease in shrimp, Fenneropenaeus indicus. The experimental design included three groups, one treatment as infected shrimp or group B and 2 controls with non-infected but exposure to White Spot Syndrome Virus (WSSV) shrimp as group A and non-infected non-exposure to WSSV shrimp as group C in triplicate. The results revealed that Hemocytosis associated with a decrease in hyalinocytes and large-granulocytes (less than 8%) and a considerable increase in semi-granulocytes in group A and B in contrast to group C that Hyalinocyte increased. This infection made the shrimp susceptible to WSSV disease. It is believed that Hemocytosis causes a condition which can result in a rapid mortality among susceptible species, F. indicus when exposure to WSSV is occurred

Study on effects of Beta-glucan & extraction of Sargassum & Padina algae in prevention and treatment of WSD in Fenneropenaeus indicus

In this study two species of algae, Sargassum glaucescens and Padina boergeseni that found plenteously in Persian Gulf and Bushehr coast, were collected and hot water extracts of them were lyophilized. F. indicus (11.32±1.20 g), after two weeks adaptation in Shoghab research station were immersed in seawater (39 ppt and 25±1 ○C) containing hot-water extract of each brown algae, S.glaucescens and P.boergeseni, at 100, 300 and 500 mg/l concentration, Survival rate and immunological parameters (total haemocyte count (THC), total plasma protein (TPP), Phagocytic activity, bacterial clearance efficiency and bactericidal activity) were examined. In addition effect of dietary administration of beta 1, 3 1, 6 glucan on prevention of White Spot Disease and immunological parameters of shrimp were investigated. According to results, immersion in seawater containing 300 and 500 mg/l concentration of algal hot-water extract after 2 and 3 hours or oral administration of beta 1,3 1,6 glucan at level of 10 g/kg diet for 14 days significantly enhanced THC, TPP, Phagocytic activity, bacterial clearance efficiency and bactericidal activity. Immersion in seawater containing 100, 300 and 500 mg/l hot-water extract of S.glaucescens after 3 hours, improved the survival rate of WSSV-infected F. indicus

Survey on white spot virus infection in wild shrimps and crabs in Bushehr province coastal waters

After severe mortality due to white spot disease incidence in cultured shrimps of Helleh grows out farms, disease spread to Delvar,Mond, Boeyrat and Bandar Rig sites in Bushehr province during 2005. Many crustaceans keep this virus in the body, act as a carrier, and can spread of the infection. In order to investigate status of contamination of wild shrimp and crab's population to white spot virus in Bushehr province waters (north of Persian Gulf), samples were collected and tested by Nested PCR for detection of WSV from estuaries and input and output channels water around the Helleh, Shif and Mond sites during 2007 and 2008. Total tested shrimps were 401 peaces, includes green tiger shrimp (Penaeus semisulcatus) 220 pieces, white shrimp (Metapenaeus affinis) 181 pieces, also total tested crabs were 292 pieces includes Ocypode rotundata 68 pieces and Portunus pelagicus 224 pieces. All the samples showed negative results of WSV contamination. However, it can never be sure that the population is free from WSV unless we collect a random sample of 300 pieces from each species and test them individually for WSV. Therefore, we will be confident up to 95% that the wild sources in that area have no prevalence of 1% or upper WSV contamination

Study of growth, survival rate and final harvesting of Litopenaeus vannamei impact of 25, 35 and 50 (per/m^2) stocking densities

For the first time in research program and species diversity the white legged shrimp (Litopenaeus vannamei) was introduced in Iran in 2005 by Iranian Fisheries Research Organization. In two recent years two projects was carried out successfully in Hele Research Station and according of these projects study of growth, survival rate and final harvesting of Litopenaeus vannamei impact of 25, 35 and 50 (per/m^2) stocking densities was done .Nine 0.4 ha earthen ponds were stocked from 26 June 2006 to 11 November 2006 and the rate of stocking was 100000,140000 and 200000 Pl in 25, 35 and 50 per /m^2 respectively. We also carried out daily test of pH, temperature and dissolve oxygen two times per day but transparency, depth and salinity one time per day. The mean weight in 120 days was 17/84±2/6, 16/03±1/9 and14/09±2/3 grams in 25, 35 and 50 per /m^2 respectively and highest weight was seen in 25 density. Results demonstrated that there was a significant relation (P<0.05) between mean weight. The yield were 1745, 2055 and 2425 kg/pond although 4/3, 5/1 and 6 ton/ha in 25, 35 and 50 per /m^3 respectively. The maximum and minimum survival rate 97/96 and 88/46 was seen in 25 and 50 per/m^2. The minimum FCR 1.43 was seen in 25 per /m^2. For economical calculating just by using the cost of larva and feeding indicates that the highest benefit percentage was seen in 25 density. The average of salinity, pH, temperature and dissolve oxygen were 36.1-37 ppt, 8.1, 30.2-30.6 degrees centigrade and 5.9- 6.4 mg/l

Determination of biotechniqe and bionormative of breeding and culturing of Penaeus merguiensis de Man in Bushehr Area

To introduce the native commercial shrimp species to aquaculture industry, the Iranian Fisheries Research Organization conducted a project to investigate the possibility of reproduction and cultivation of the banana shrimp (Penaeus merguensis). The present work has been carried out from 21st March 2001 in two phase, reproduction and cultivation, in Iran Shrimp Research Center. The main objectives of this study was to find the possibility of reproduction and cultivation of banana shrimp with emphasis on its cost and benefit and to find if this species could be introduced to aquaculture industry in Iran. In this work, 42 brood stocks of banana shrimp caught in Jask waters and were transported to Bushehr. The shrimps were reproduced in aquaculture research station, and then cultivated in 0.4 ha ponds in Heleh region. Most of the broodstocks perished, due to long distance of Jask from Bushehr province, or had problem in hatching. Finally 8 of broodstock shrimps spawned. In 3 cases, the reared naplii larva suffered high mortality, but the other 5 spawner’s bread successfully. The post larvae were introduced to the shrimp ponds. The primary stocking was 360,000 larvae, introduced to each of two 4 m 3 tanks. The survival in both tanks for mysis stage was 83% but for PL stages, the survival was 5% for Tank 1 due to disease outbreak (until PL 24), and 62% for Tank 2. On 10 th June 2001 the PL 24 were stocked into the ponds but unfortunately due to adaptation problem, all of the shrimps perished. It seems that banana shrimp couldn’t to be adapted to the pond condition in Heleh region. On the basis of the results, the reproduction of the banana shrimps is achievable, but broodstocks needs to be transferred to reproduction areas as soon as possible to reduce stress on the shrimps. Our finding shows that the optimum conditions of salinity and temperature for growth of the reared banana shrimp in Heleh region is 33ppt and 30 °C, respectively

Molecular identification of bacterial and fungal pathogens in certain disease-free shrimp

At present, the aquaculture industry to provide proper instructions in the field of health management, including production of Specific Pathogen Free shrimp (SPF), require sensitive and reliable methods for the detection and identification of pathogenic microorganisms. Molecular methods which used in the detection of microorganisms have a high discriminatory power in the taxonomy and in relation to libraries in the world. On the other hand, the accurate identification of microorganisms, providing the genetic data bank of shrimp pathogens and maintenance of these strains is the step to promote further research on the mechanisms of pathogenesis of pathogens, diagnosis, treatment, prevention of disease, identify indigenous production kits, diagnosis re emerging and emerging diseases and their origin. Therefore, in this project, by using ribotyping technique, native isolated pathogenic bacteria and fungi were identified and recorded in the gene bank database center. During sampling of shrimp and water of Specific Pathogen Free shrimp center, 40 bacterial strains were isolated, which 8 of them had the most frequency and identification based on 16S rDNA sequencing was performed. Bacteria identified are: Vibrio nigripulchritudo strain IS013(GenBank:KP843725), Vibrio brasiliensis strain IS014 (GenBank:KR186076), Vibrio rotiferianus strain IS015 (GenBank:KR186077), Vibrio azureus strain IS012 (GenBank:KJ018724.1), Vibrio owensii strain IS016 (GenBank:KR186078), Agarivorans gilvus strain IS017 (GenBank:KR186079), Vibrio brasiliensis IS018 (GenBank:KR186080) and Vibrio alginolyticus strain IS019 (GenBank:1817854), which were recorded in The World Bank genes. In this study fungal isolates were not detected