Shrimps are infected by numerous pathogenic microbes which caused high mortality. The excess feed and fecal matter in grow out ponds accumulating in the impoundments may result in bacterial decomposition of organic matter in the sediment and produce excess of toxic compounds like ammonia and also pollute the environment.
Very limited research has been carried out on the culture, growth performance and disease management in aquaculture using beneficial microbes. Moreover, in the beginning years of aquaculture the antibiotics were employed to kill the microbial pathogens and to enhance the growth of the shrimps in intensive and semi-intensive types of culture.
The excess use of antibiotics has created the problem of residue buildup in tissue of shrimps, resistance of culture species to the consistent use of antibiotics and rejection of export consignments etc. As a remediation of these unpleasant and unwanted problems in aquaculture there is a need of beneficial microbes in shrimp culture through feed and/or water to prevent the aquaculture ponds from undergoing eutrophication and to control the microbial diseases in shrimps and to enhance their production in an ecofriendly ambience without the use antibiotics thus, resulting in quality assurance, quality control and above all environmental safety.
Introduction
Aquaculture is an emerging branch of biosciences boosting food production. The marine fisheries stocks have declined worldwide in general and provided an impetus for rapid development in fish and shellfish farming.
In general, shrimp ponds are enclosed cultivation systems, subject to periodic water renewal to compensate for volume changes (due to evaporation) and salinity changes (evaporation, precipitation) and to maintain water quality. The production process in shrimp aquaculture is determined by biological, technological, economical and environmental factors (Yuvaraj and Karthik, 2015 b).
Especially, the microbial diseases are commonly implicated in episodes of mortality, so that our Indian farmers prefer to use commercial antibiotics available in markets. However, the use of antibiotics has recently become a major public concern because their use can lead to the development of drug resistant bacteria, thereby reducing drug efficacy.
Moreover, the accumulation of antibiotics both in the environment and in shrimp tissues can be potentially risky to consumers and the environment. Another most important problem faced by our Indian shrimp culture farmer is excess of Ammonia in pond water and sediment which is caused by excess feed, fecal matter and dead algae deposited in the bottom of the pond. Due to this, shrimps are exposed to toxic gases like NH3, NO2 and H2S further leads to eutrophication in culture system and cause stress to the animal and ultimately end with microbial diseases and high mortality occurs (Yuvaraj et al., 2015 a).
Though shrimp culture has undergone rapid development in India, successful production is increasingly hampered especially by diseases in addition to environmental pollution and poor management practices.
Of all the infectious diseases, bacterial infections cause serious diseases like vibriosis, White spot, ulcer, tail rot, necrosis etc. Currently, antibiotics have been widely used in shrimp aquaculture to control bacterial infections. However, the use of antibiotics has recently become a major public concern because their use can lead to the development of drug resistant bacteria, thereby reducing drug efficacy. Moreover, the accumulation of antibiotics both in the environment and in shrimp tissues can be potentially risky to consumers and the environment. Such adverse effects have prompted scientists to search for alternatives to replace antibiotics in controlling diseases in shrimp farms (Karthik et al., 2013 & 2014).
