Survey of fungal flora infecting P. indicus in larvae stages in hatcheries of Khouzestan Province, south Iran

Shrimp hatcheries around the world continue to be heavily dependent of wild broodstock. One of the factors that could damage this industry is fungal infestation. Hence, we studied the fungal flora infesting shrimp larvae in hatcheries of Khouzestan Province, south Iran. The study covered two reproduction periods 2001=2002 and totally 140 specimens were collected from 2 hatcheries under Thailand and Philippine management systems. Samples were obtained in completely sterile condition from water, live food and different stages of shrimp larvae P. indices. The samples were cultured on SDA, PYGA, PYGSA and similar media. We diagnosed ten fungal species including Cladosporium sp, Pencillium, Trichothesium sp., Aspergilus sp. A. niger, Rhizopus, Mucor and Fusarium, the last being the most abundant fungus. We found that the contaminating fungal species were all opportunistic

A Study on population genetic of Hilsa shad, Tenualosa ilisha, in Khouzestan, Iran using molecular method (RAPD)

The genetic structure of Hilsa Shad Tenualosa ilisha in Khouzestan waters including Karoon, Arvandrood and Bahmanshir Rivers as well as Persian Gulf was studied using RAPD technique. After optimizing PCR condition, nine RAPD primers were selected from which 58 polymorphic loci were obtained on 12 specimens from each geographical region (A total of 48 specimens). RAPDPLOT, RAPDDIST and POPGENE computer software were used to analyze the RAPD data. Canonical discriminant analysis was deployed for statistical assessment of the RAPD data. Maximum and minimum genetic distances were found between samples from Arvandrood River and Persian Gulf (0.1987) and Arvandrood and Bahmanshir Rivers (0.0852), respectively. The UPGMA dendrogram showed that the samples from Karoon River and Persian Gulf form one group and samples from Arvandrood and Bahmanshir Rivers form another suggesting the hypothesis that there are Iranian and Iraqi populations of the species that chose their own specific rivers for spawning. According to this hypothesis, the specimens from Persian Gulf chose Karoon as their spawning river. Other populations migrate to Tigris and Euphrates Rivers in Iraq

Comparison of four RNA isolating methods for identification of spring viraemia of carp virus (SVCV)

Spring viraemia of carp virus (SVCV), a negative sense single stranded RNA virus of the family Rhabdoviridae, is the causative agent of a highly contagious SVC disease that primarily affects the common carp (Cyprinus carpio), an economically important fresh water fish species with world-wide distribution.SVCV has also been reported to cause disease in other fishes such as Poeciliidae, Esocida , Centrarchidae , Siluridae and salmonidae . There are several diagnostic tests for the detection of SVC virus,however, the tests have not been validated. The reverse transcriptase – polymerase chain reaction (RT-PCR) techniques have been developed and validated representing a powerful tool for detection of RNA. One of the most important aspects isolating RNA is to prevent degradation of the RNA during the isolation procedure. In this study, we explored the efficiency of protocols for RNA isolation from the SVCV strain 56/70. For RNA isolation, we compared four protocols, two guanidine isotiocyanate phenol – chloroform based protocols (RNX – Plus Iran, Iq2000 kit Taiwan) and two column based protocols (Cinnapure RNA Iran, high pure viral RNA kit, Roche Germany) that were commercially available. The results showed that the column based protocols, Roche method and Cinapure performed better than other methods with the yields of 31.76 ng/µl, 16/21 ng/µl, respectively. Each protocol yielded good quality of total RNA bands (480 bp) being observed in agarose gel electrophoreses but was not observed in IQ2000 kit. Amount of total RNA isolated was lower for IQ2000 kit Protocol. Further, the RNA being extracted from SVC by column based protocol method were resulted in successful amplified using RT-PCR method

Physico-chemical properties of water in shrimp hatcheries of Choebdeh (Abadan), south Iran

For assessing management efficiency in shrimp hatcheries of Choebdeh (Abadan), we surveyed the physico-chemical properties of water in two culture periods during the years 2001-2002. Different physical and chemical factors were measured in hatcheries under Thai and Philippine management methods. We measured factors such as salinity (17.9-35.3 ppt), BOD5 (6.12-8.72 ppm), DO (10.02-13.7 ppm), COD (4-98.9 ppm), NH3 (0-811A ppb), NO2 (10421 ppb), pH (8.04 -8.68), Turbidity (1-33 NTU), Ca (400.4-620.6 ppm), Mg (1104-1968 ppm), total hardness (6000-9400 ppm) and water temperature {25.4-32.4°C) while no amount of SH2 was found in the water samples. The results of this survey were compared with standard levels and safe ranges for aquaculture activities. Most factors were in standard range with only NH3 and NO2 showing a slight excess in some cases. An ANOVA test showed significant differences in levels of oxygen and COD of the tanks at different sampling times

Effect of salinity on spawning of yellow fin sea bream (Acanthopagrus latus) in spawning tanks

Salinity effects on brooders spawning, growth and survival rate of yellow fin sea bream (Acanthopagrus latus) fingerlings was studied in Khouzestan Marine Fishes Research Station (Bandar-e Imam) in 2002- 2003. More than 200 brooders were caught in Mahshar creeks using hook, and 6 males and 3 females of brooders were introduced to each 4 tons tank. The experiments were carried out using 3 salinity treatments (30±1, 35±1 and 40±1 ppt) in 3 replications. Survival rate of brooders in 4 tons tanks during late January to 4^th April was estimated more than %90 in all salinities and the maximum rate was observed in 30 ppt treatment. Spawned brooders percentage in 40 ppt was more than the two other salinities, and spawning occurred in all three replications of this treatment. In all treatment, spawning started from early march (late lunar month) at 19~'C and continued at 23°C. Duration and replication of spawnings in 40 ppt were more than other salinities, and last about 20 days. Released eggs (2461046), amount of eggs production per day (66413), average number of eggs per brooder (312914), and average eggs per kg body weight (649460) were found in 40 ppt more than other salinities. Floating eggs ratio was more than %90 in 40 ppt and it was significantly different to the others. Fertilization and hatching rates in 40 ppt treatment (86.7, 67 respectively) were more than 30 and 35 ppt but there was no significant difference. All spawnings cases , released eggs hatched

A study on immunological factors in white spot vaccinated shrimp, Litopenaeus vannamei in comparison to none vaccinated groups

The aim of this study was to evaluate the efficacy of white spot virus vaccine produced by gamma irradiation in the face of Litopenaeus vannamei in comparison with Gracilaria corticata and Saccharomyces cerevisiae Seven hundred and twenty healthy shrimp SPF L. vannamei subadult with average weight of 10±1.02 g were collected and divided into 8 groups. The first group (T1) was fed with commercial pellet as control. The second group (T2) was fed with S. cerevisiae added to shrimp feed (1 g/Kg), the third group (T3) G. corticata so that algae Gracilaria were dried and added to shrimp feed at the rate of 1500 mg per kg and finally, the fourth group (T4) was vaccination group which the shrimp were exposed to the vaccine and injected intramuscularly gamma irradiant WSSV (1µl/gbw) for 10 days. The shrimps of all groups were then injected with WSSV and maintained for 25 days. Results indicated that the survival rates for groups T4, T3 T2 and T1 were 57.05±3.52%, 22.5±0.5%, 15±1.05% and 00.0±0%, respectively. Ultimately, at the end of the study the shrimp group T4 showed higher hematological data: THC, TPP, SOD, POD and PO. The study concluded that gamma irradiant WSSV is effective immunostimulants in shrimp L. vannamei and the immunity has better performances than those of the G. corticata and S. cerevisiae