مقالههای M Afsharnasab
توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
۱Screening and evaluation of indigenous bacteria from the Persian Gulf as a probiotic and biocontrol agent against Vibrio harveyi in Litopenaeus vannamei post larvae
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، دوازدهم،شماره۴، oct ۲۰۱۳، سال ۰
تعداد صفحات: ۱۴
Isolation of autochthonous bacteria from marine sources as a potential probiont in biocontroling against pathogenic Vibrio species in the shrimp culture industry was the aim of current research. A total of 198 bacterial strains were isolated from pond water, sediment, hepatopancreas and gut samples of shrimps after culturing the samples on Tryptic Soy Agar and incubated at 30 °C for 24–48 h. The isolates were tested for their antagonistic activity in contact with Vibrio harveyi. Two strains (IS02 and IS03) that isolated from the gut and pond sediment were showed antagonistic against V. harveyi. According to 16S ribosomal DNA gene sequence analysis, the strain IS02 was identified as Bacillus subtilis and IS03 as B.vallismortis. Further, the two bacterial species, B. subtilis and B. vallismortis were challenged separately for probiotic activity in the post larvae of Litopenaeusvannamei against pathogenic V. harveyi. The present study identified B.subtilis IS02 and B.vallismortis IS03 had biocontrol activity against V. harveyiin vitro and in vivo and they increase growth performance of L.vannamei in post larvae stage.
۲Effects of temperature on hematological and histopathological changes and survival rate of juvenile Fenneropenaeus vannamei experimentally challenged to White Spot Virus
نویسنده(ها): S Kakoolaki *، I Sharifpour، M Afsharnasab، A Sepahdari، M. R Mehrabi، B Ghaednia، H Nezamabadi
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، سيزدهم،شماره۱، Jan ۲۰۱۴، سال ۰
تعداد صفحات: ۱۲
Many shrimp farmers were suffering from White Spot Disease (WSD) onset in last decades. Oscillation of environmental factors could lead mortality in susceptible hosts. Our study was aimed to investigate the effect of different temperatures on juvenile Fenneropenaeus vannamei experimentally exposed to White Spot Virus (WSV). Five hundred and forty juveniles were distributed among 3 treatments in triplicates, 22, 25 and 30°C and experimentally WSV were injected in the shrimps. Our results showed mortality started at 36 h post inoculation (hpi) in the treatment at 25°C (T25), meanwhile the mean value of mortality percent at 54 hpi in T25 (71.10±17.35) showed the significant difference (p=.045) with T22 (3.33±3.33) and T30 (Not Observed, NO.). Our results suggest that in site selection, in primary stage of farm designing, water temperature at more than 29°C, should be considered as key environmental factor. This finding can lead us that why the White Spot Disease occurred with high mortality in some area when the days of shrimp culture were prolonged until mid autumn.
۳Molecular Identification of Vibrio harveyi From Larval Stage of Pacific White Shrimp (Litopenaeus vannamei) Boone (Crustacea:Decapoda)By Polymerase Chain Reaction and 16S rDNA Sequencing
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، سيزدهم،شماره۲، Apr ۲۰۱۴، سال ۰
تعداد صفحات: ۱۰
A Gram–negative, rod–shaped, motile and halophilic bacterium identified as Vibrio harveyi was isolated from hatchery–reared larval of Iran Shrimp Research Centerfollowing mass mortality . Seven isolates of Vibrio spp.were collected from nauplii of Litopenaeus vannamei and then were evaluated for characteristics including morphology, physiology and biochemistry. The results indicated that the isolates belonged to a single species that grew on Thiosulfate citrate– Bile Sucrose agar and in 1.5 to 6% NaCl, positive lysine and ornithine decarboxylation and susceptible to O\129 disk. Identification of Vibrio harveyi strainIS01 (1 of 7 isolates) was confirmed by Polymerase Chain Reaction assay for Vibrio harveyi (expected amplicon 1493 bp). The 16S ribosomal DNA sequence (National Center for Biotechnology Information, GenBank accession number GU974342.1) gave 99% sequence identity to V. harveyi ATCC: 35084 (GenBank accession number EU130475.1).
۴Protozoan epibionts on Astacus leptodactylus (Eschscholtz, 1823) from Aras Reservoir, Northwest Iran
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، چهاردهم،شماره۲، Apr ۲۰۱۵، سال ۰
تعداد صفحات: ۱۳
The Astacus leptodactylus specimens were collected from four sites of Aras reservoir, North–West of Iran and examined for the epibionts during 2009. Protozoan epibionts from ciliophora (one genus and seven species) and tracheophyta were isolated from the cuticular surface of different body parts of narrow–claw crayfish, A.leptodactylus. Seasonal prevalence of infestation was determined in 394 individuals of A.leptodactylus. The facultative ciliate Tetrahymena pyriformis was identified on the gills and gill haemocoel with 0.5% prevalence. Futhermore , epibiont fouling organisms such as Epistylis chrysemidis (52.3%); Vorticella similis (45.9%); Cothurnia sieboldii (68.5%); Pyxicola annulata (66%); Chilodonella spp.(0.5%); Zoothamnium intermedium(57.1%); Opercularia articulate (20.6%) and Podophrya fixa (8.6%) were also isolated from 13 body parts of A.leptodactylus. The presence of Chilodonella infestation is the first record of this genus on freshwater crayfish species. The comparison of biometrical data of the epibionts showed no significant differences in prevalence of seasonal infestation between sampling sites. The current work represents the first documentation for the presence of protozoan epibionts on A.leptodactylus in Aras Reservoir, Iran.
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