Distribution of luminescent Vibrio harveyi and their bacteriophages in a commercial shrimp hatchery in South India

Luminescent Vibrio harveyi is a natural microflora of marine and coastal water bodies and is associated with mortality of larval shrimp in penaeid shrimp hatcheries. It is also known that the bacteriophages occur virtually in all places where their hosts exist. In this study, distribution of luminescent V. harveyi and the bacteriophages affecting these hosts was examined in a commercial Penaeus monodon hatchery during three shrimp larval production cycles, including a cycle affected by luminescent bacterial (LB) disease outbreak

A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system

Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants

Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy

Not Available

Not AvailableThe present study aimed to develop bioactive edible coating (BEC) solutions from gelatin and chitosan,incorporated with different concentrations of clove oil as a natural preservative and evaluate their effect on shelf life of tuna fillets. The antibacterial activity against 11 fish spoilage and fish-borne bacteria were tested by agar well diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Gram positive bacteria were more susceptible than gram negative bacteria. Among all the tested bacteria, Bacillus cereus and Staphylococcus aureus were most sensitive to BEC solutions. The tuna fillets were dipped in BEC solutions with different concentrations viz., 1%Acetic acid, 1% Chitosan (C), 1% Gelatin + 1% Clove oil (GC), 1% Chitosan + 1% Clove oil (CC), 1%Gelatin + 1% Chitosan + 1% Clove oil (GCC) and changes in APC, TBARS, TVB-N and sensory values were studied during storage under refrigerated condition (4°C). The fillets without dip treatment was considered as control. Dip treatment of BEC solutions significantly delayed the rate of microbials poilage and extended the shelf life of tuna fillets by six days during refrigerated storage. Solutions incorporated with clove oil, especially fillets treated with 1% gelatin + 1% chitosan + 1% clove oil (GCC)solution had better in-vitro antimicrobial properties and showed excellent preservative action on tuna fillets. The BEC solutions incorporated with clove oil demonstrated its potential as an excellent natural antibacterial agent which can be used as an effective alternative to synthetic antibacterial agents and could be used for packaging of tuna and other fishery products.Not Availabl

Not Available

Not AvailableSeasonal variation in the proximate composition (moisture, protein, fat, carbohydrate and ash) was analysed in emperor fish (Lethrinus lentjan). Mineral composition (iron, phosphorus, sodium, potassium and calcium) was also analysed. Moisture, protein, fat, carbohydrate and ash contents were found to range from 74.93–78.20, 14.53–24.40, 0.21–2.76, 0.49– 1.07 and 1.24–2.70% respectively. Iron, phosphorus, sodium, calcium and potassium was 4.20, 13.50, 7.20, 156.20 and 17.90 mg% respectively. Fatty acid profile of emperor fish revealed palmitic acid (C16), stearic acid (C18) and myristic acid (C14) to be the major saturated fatty acid and elaidic acid (C18:1n9T) and oleic acid (C18: 1n9C) were the dominant monounsaturated fatty acids. Investigations also revealed that fat content was higher during the monsoon season (October and November).Not Availabl

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableNot AvailableNot Availabl

Antagonistic effect of bacteria associated with ascidians from Thoothukudi coast

1208-1217The antagonistic properties of marine ascidians and the bacteria associated with them were investigated. Ascidians were collected from submerged structures along the coast of Thoothukudi and four species of solitary ascidians and four colonial ascidians were identified. A total of 590 bacterial isolates from the ascidians were characterized up to generic level. All the bacterial isolates were tested for antagonistic property against indicator bacteria and 71 isolates were recognized as potentially antagonistic, however, only 9 of them could effectively inhibit test organisms that included six human and one shrimp pathogenic bacteria. The inhibitory activity of the crude extracts of extracellular products (ECP) of selected antagonistic bacteria was weak against test organisms, but the ethyl acetate crude extracts of both cells and cell free supernatants of antagonistic bacteria showed strong inhibitory activity. Extracts from DS13, DP41 and P19 showed a high degree of inhibition. Methanol crude extract of Eudistoma viride showed good inhibitory activity against Vibrio cholerae and V. harveyi

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableLuminescent Vibrio harveyi is a natural microflora of marine and coastal water bodies and is associated with mortality of larval shrimp in penaeid shrimp hatcheries. It is also known that the bacteriophages occur virtually in all places where their hosts exist. In this study, distribution of luminescent V. harveyi and the bacteriophages affecting these hosts was examined in a commercial Penaeus monodon hatchery during three shrimp larval production cycles, including a cycle affected by luminescent bacterial (LB) disease outbreak.Not Availabl