Probiotic Potential of an Indigenous Marine Bacillus thuringiensis on Shrimp (Penaeus monodon) Culture Infected with Vibrio mimicus

The present study investigated the outbreak of white spot disease (WSD) in association with Vibrio mimicus infection, which occurred twice consecutively in a black tiger shrimp (Penaeus monodon) farm located in the Sunderbans, West Bengal, India. The farm stocked with post-larvae (PL) @ 16 PL m-2, encountered disease outbreak on the 41st day of culture (DOC) followed by a second outbreak on the 54th DOC with 100% mortality each time. Shrimp samples were collected for molecular diagnosis as well as for microbiological investigations. White spot syndrome virus (WSSV) infection was confirmed by polymerase chain reaction (PCR). V. mimicus isolated from the outbreak, was characterised by morphological, physiological and biochemical characteristics. V. mimicus isolated was found to be pathogenic by challenge studies which caused 100% mortality in P. monodon juveniles. Microbial load was studied in the natural infection and also in challenge trials in relation to the day of advancing infection. LD50 value for V. mimicus, isolated from the outbreak, was 107.32 in P. monodon juveniles. Co-infection of V. mimicus with WSSV led to 100% mortality within seven days from the onset of clinical signs.

Download Full-text

Bioprospecting of an Indigeneous Bacillus thuringiensis Strain G5-8-3T02 for Shrimp Culture System

South Asian Journal of Research in Microbiology ◽

10.9734/sajrm/2020/v6i130142 ◽

2020 ◽

pp. 33-43

Author(s):

Caroline Nchedo Ariole ◽

Euphemia Uchechi Agulanna

Keyword(s):

Antibacterial Activity ◽

Bacillus Thuringiensis ◽

Bioactive Compounds ◽

Culture System ◽

Sodium Dodecyl ◽

Quantitative Composition ◽

Potential Candidate ◽

Shrimp Culture ◽

Vibrio Mimicus ◽

Thuringiensis Strain

Aim: An indigenous Bacillus thuringiensis strain G5-8-3T02 earlier isolated from healthy shrimp intestine and established to safeguard Penaeus monodon from Vibrio mimicus infection was assessed as a potential candidate bacterium for drug enhancement for shrimp culture systems. Methodology: Optimal temperature, pH and salinity for growth and antibacterial activity of Bacillus thuringiensis against Vibrio mimicus were determined. The effects of enzymes (pepsin, catalase, lipase and α- amylase), pH (2-9), heat (37°C – 121°C) and surfactants (Sodium dodecyl sulphate and Tween 80) on antibacterial activity were also evaluated. Cell growth and antibacterial activity were monitored daily for 5 days via spectrophotometric method at 600 nm and agar well diffusion assay respectively. The metabolite extracted with methanol was analyzed for bioactive compounds using Gas Chromatography-Mass Spectrometry (GC-MS). Results: The optimum temperature, pH and salinity for growth and metabolite production were 35°C, pH 6-7 and 10-15 ppt. respectively. The crude extract did not totally lose its activity when treated with enzymes, various pH values, heat and surfactants. The quantitative composition of the metabolite revealed 15 bioactive compounds. The main compound produced was 2, 6, 10-Trimethyltridecane with peak area of 14.58%. Conclusion: The non-pathogenic, antagonistic, indigenous Bacillus thuringiensis strain G5-8-3T02 could be engaged in the management of vibriosis in shrimp culture since the use of antibiotics in aquaculture for disease control yields objectionable effects. The identified bioactive compounds might be valuable for drug development for shrimp culture system.

Download Full-text

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

Diseases of Aquatic Organisms ◽

10.3354/dao03475 ◽

2020 ◽

Vol 139 ◽

pp. 153-160

Author(s):

S Peeralil ◽

TC Joseph ◽

V Murugadas ◽

PG Akhilnath ◽

VN Sreejith ◽

...

Keyword(s):

Gene Expression ◽

Virulence Genes ◽

Vibrio Harveyi ◽

Penaeus Monodon ◽

Challenge Test ◽

Virulence Gene ◽

Economic Losses ◽

Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

Download Full-text

Presence of Penaeus monodon densovirus in the ovary of chronically infected P. monodon subadults

Diseases of Aquatic Organisms ◽

10.3354/dao03241 ◽

2018 ◽

Vol 129 (3) ◽

pp. 183-191 ◽

Cited By ~ 1

Author(s):

S Fernando ◽

P Attasart ◽

SR Krishna ◽

B Withyachumnarnkul ◽

R Vanichviriyakit

Keyword(s):

Penaeus Monodon

Download Full-text

Prevalence, diversity and co-occurrence of the white spot syndrome virus, monodon baculovirus and Penaeus stylirostris densovirus in wild populations of Penaeus monodon in the Philippines

Diseases of Aquatic Organisms ◽

10.3354/dao03150 ◽

2017 ◽

Vol 125 (3) ◽

pp. 199-206

Author(s):

FL Orosco ◽

AO Lluisma

Keyword(s):

White Spot Syndrome Virus ◽

Penaeus Monodon ◽

The Philippines ◽

White Spot ◽

Wild Populations ◽

White Spot Syndrome ◽

Penaeus Stylirostris Densovirus

Download Full-text

Dynamics of fatty acid regulatory genes during ovarian development in Penaeus monodon

Reproduction ◽

10.1530/rep-18-0143 ◽

2018 ◽

Cited By ~ 1

Author(s):

Pacharawan Deenarn ◽

Punsa Tobwor ◽

Rungnapa Leelatanawit ◽

Somjai Wongtriphop ◽

Jutatip Khudet ◽

...

Keyword(s):

Fatty Acid ◽

Ovarian Development ◽

Penaeus Monodon ◽

Chain Fatty Acid ◽

Regulatory Genes ◽

Ovarian Maturation ◽

Long Chain Fatty Acid ◽

Eyestalk Ablation ◽

Regulatory Pathways ◽

Expression Levels

The delay in ovarian maturation in farmed black tiger shrimp Penaeus monodon has resulted in the widespread practice of feeding broodstock with the polychaetes Perinereis nuntia and their unilateral eyestalk ablation. Although this practice alters fatty acid content in shrimp ovaries and hepatopancreas, its effects on fatty acid regulatory genes have yet to be systematically examined. Here, microarray analysis was performed on hepatopancreas and ovary cDNA collected from P. monodon at different ovarian maturation stages, revealing that 72 and 58 genes in fatty acid regulatory pathways were differentially expressed in hepatopancreas and ovaries respectively. Quantitative real-time PCR analysis revealed that ovarian maturation was associated with higher expression levels of acetyl-CoA acetyltransferase, acyl-CoA dehydrogenase, acyl-CoA oxidase 3 and long-chain fatty acid transport protein 4 in hepatopancreas, whereas the expression levels of 15 fatty acid regulatory genes were increased in shrimp ovaries. To distinguish the effects of different treatments, transcriptional changes were examined in P. monodon with stage 1 ovaries before polychaete feeding, after one-month of polychaete feeding and after eyestalk ablation. Polychaete feeding resulted in lower expression levels of enoyl-CoA hydratase and acyl-CoA synthetase medium-chain family member 4, while the expression level of phosphatidylinositide phosphatase SAC1 was higher in shrimp hepatopancreas and ovaries. Additionally, eyestalk ablation resulted in a higher expression level of long-chain fatty acid-CoA ligase 4 in both tissues. Together, our findings describe the dynamics of fatty acid regulatory pathways during crustacean ovarian development and provide potential target genes for alternatives to eyestalk ablation in the future.

Download Full-text