Marine Actinomycetes as Source of Antiviral Agents and as Probionts for Penaeus monodon Culture Systems

The present study revealed the importance of marine actinomycetes as a potent source of bio active secondary metabolites. The selected isolates were capable of protecting Peaneus monodon against WSSV infection. They also proved to be inhibitory to vibrios and is a rich pool of hydrolytic enzymes. Their capacity to proliferate in saline environments and their property of non-pathogenicity to prawns makes them good candidates to be applied as probionts in penaeid shrimp aquaculture. They also enhanced the immune status of shrimps challenged with WSSV and act as a good source of antioxidants. Exploitation of the potential for the prophylactic and therapeutic measures in aquatic animal health management would be highly rewarding. This work is a preliminary study targeting marine actinomycetes as a source of antiviral compounds and as probionts in Penaeus monodon culture systems. More work is needed to understand the nature and mode of action of the bioactive compound, the various aspects of immune and antioxidant responses under challenge and when exposed to pro active treatments, and the dose and frequency of application of such compounds under rearing conditions.

Mangrove plant Ceriops tagal as a potential source of anti White Spot Syndrome Virus preparations for Penaeus monodon

White spot syndrome virus (WSSV) is the deadliest virus among crustaceans ever discovered having several unique and novel features. Recent developments in genomics and proteomics could elucidate the molecular process involved in the WSSV infection and the host pathogen interaction to some extent. Until now no fool proof treatment or prophylactic measure has been made available to control WSSV out breaks in culture system. Even though there are technologies like application of immunostimulants, vaccines, RNAi and several antiviral natural products none of them has been taken to the level of clinical trials. However, there are several management options such as application of bioremediation technologies to maintain the required environmental quality, maintenance of zero water exchange systems coupled with application of probiotics and vaccines which on adoption shall pave way for successful crops amidst the rapid spread of the virus. In this context the present work was undertaken to develop a drug from mangrove plants for protecting shrimp from WSSV.Mangroves belong to those ecosystems that are presently under the threat of destruction, diversion and blatant attack in the name of so called ‘developmental activities’. Mangrove plants have unique ecological features as it serves as an ecotone between marine and terrestrial ecosystem and hence possess diversity of metabolites with diverse activities. This prompted them being used as remedial measures for several ailments for ages. Among the mangrove plants Ceriops tagal, belonging to the family Rhizophororaceae was in attention for many years for isolating new metabolites such as triterpenes, phenolic compounds, etc. Even though there were attempts to study various plant extracts to develop anti-viral preparations their activity against WSSV was not investigated as yet.

A marine candida sake as source of immunostimulants to fenneropenaeus indicus

Aquaculture has developed rapidly over the last three decades to become an important activity worldwide.The Food and Agricultural Organization (FAO) of the UN acknowledge that global fishery output must be increased by at least 50% to offset projected shortfalls in dietary protein by 2030.LAquaculture has developed rapidly over the last three decades and has become an importat industry as today’s demand for fish exceeds the natural supply.lmmunostimulants are chemical compounds that activate the immune system of animals and render them more resistant to infections by viruses, bacteria, fungi, and parasites. lmmunostimulants have been obtained from diverse natural sources where, microbial cell wall acts as the main source.The salient findings of the study are summariseSeven marine yeasts were screened for growth promoting and immunostimulant property in F. indicus. Candida sake S165 was found to be best in terms of its support for growth and protection against white spot virus infection.The study revealed that marine yeast Candida sake can be effectively used as potential source of immunostimulants for application in penaeid prawns culture systems. The study emphasise the fact that the dose and frequency of application of immunostimulants are to be standardised and validated before commercialisation to achieve optimum stimulation of the immune system and to avoid immune fatigue die to verdose.Marine yeast (whole cell) was found to support better immunostimulation compared to its cell wall component B-1,3-glucan. This study shows that administration of marine yeast (whole cell) or B-1,3-glucan as immunostimulants in aquaculture would definitely help in protection of the stock to a few more days even though total protection is not being imparted. This partial protection itself would be highly helpful to the farming industry so that they can get sufficient time to plan for a safe harvest and save the crop from cent percent mortality.

In vivo screening of mangrove plants for anti WSSV activity in Penaeus monodon, and evaluation of Ceriops tagal as a potential source of antiviral molecules

The objective of the study was to find out a natural way to fight white spot syndrome virus (WSSV) in cultured shrimps, as the present scenario necessitated an organic remedy for the devastating pathogen in crustaceans. Under this research programme seven mangrove plants were collected, identified and aqueous extracts screened for their protective effect on the giant tiger shrimp Penaeus monodon against WSSV. The experimental design consisted two modes of application, such as exposure of the virus to the extract and injection challenge, and oral administration of the extract coated feed followed by oral challenge. All experimental animals were monitored through a nested diagnostic PCR analysis. Of the seven mangrove extracts screened aqueous extract from Ceriops tagal imparted total protection to shrimp from WSSV when challenged by both methods. Shrimps administered with the aqueous extract from C. tagal were devoid of virions. The HPLC fingerprint of the aqueous extracts from C. tagal showed more than 25 peaks and 7 of them were larger and well separated. Preliminary phytochemical analysis revealed the presence of alkaloids, flavonoids, polyphenolics, cardiac glycosides, saponins and sterols. The study indicated suitability of the aqueous extract of C. tagal as a possible prophylaxis for WSSV infection in shrimp. This is the first report on the anti WSSV property of the mangrove plant C. tagal

In vivo screening of mangrove plants for anti WSSV activity in Penaeus monodon, and evaluation of Ceriops tagal as a potential source of antiviral molecules

The objective of the study was to find out a natural way to fight white spot syndrome virus (WSSV) in cultured shrimps, as the present scenario necessitated an organic remedy for the devastating pathogen in crustaceans. Under this research programme seven mangrove plants were collected, identified and aqueous extracts screened for their protective effect on the giant tiger shrimp Penaeus monodon against WSSV. The experimental design consisted two modes of application, such as exposure of the virus to the extract and injection challenge, and oral administration of the extract coated feed followed by oral challenge. All experimental animals were monitored through a nested diagnostic PCR analysis. Of the seven mangrove extracts screened aqueous extract from Ceriops tagal imparted total protection to shrimp from WSSV when challenged by both methods. Shrimps administered with the aqueous extract from C. tagal were devoid of virions. The HPLC fingerprint of the aqueous extracts from C. tagal showed more than 25 peaks and 7 of them were larger and well separated. Preliminary phytochemical analysis revealed the presence of alkaloids, flavonoids, polyphenolics, cardiac glycosides, saponins and sterols. The study indicated suitability of the aqueous extract of C. tagal as a possible prophylaxis for WSSV infection in shrimp. This is the first report on the anti WSSV property of the mangrove plant C. tagal

Marine yeast Candida MCCF 101 as feed supplement in aquaculture: nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection

Marine yeast have been regarded as safe and showing a beneficial impact on biotechnological process. It provides better nutritional and dietary values indicating their potential application as feed supplements in aquaculture. Brown et al. (1996) evaluated all the marine yeasts characterised with high protein content, carbohydrate, good amino acid composition and high levels of saturated fats. However, there is paucity of information on marine yeasts as feed supplements and no feed formulation has been found either in literature or in market supplemented with them. This statement supported by Zhenming et al. (2006) reported still a lack of feed composed of single cell protein (SCP) from marine yeasts with high content of protein and other nutrients. Recent research has shown that marine yeasts also have highly potential uses in food, feed, medical and biofuel industries as well as marine biotechnology (Chi et al., 2009; 2010). Sajeevan et al. (2006; 2009a) and Sarlin and Philip (2011) demonstrates that the marine yeasts Candida sake served as a high quality, inexpensive nutrient source and it had proven immunostimulatory properties for cultured shrimps. This strain has been made part of the culture collection of National Centre for Aquatic Animal Health, Cochin University of Science and Technology as Candida MCCF 101. Over the years marine yeasts have been gaining increased attention in animal feed industry due to their nutritional value and immune boosting property.Therefore, the present study was undertaken, and focused on the nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection