Non specific and specific immunomodulatory efficacy of potential plant extracts in controlling major bacterial diseases in freshwater fish Labeo rohita

Abstract

Fish farming have encountered serious disease problem since past couple of years. Among the various reasons, the spread of disease depends, many factors associated with culture practices in hatcheries and nurseries. Hence for the success of aquaculture, seeds need to be of the highest quality and must be disease free (Somphouthone and Saleumphone, 2003). Sound health management practice is a key to success in any hatchery or nursery operation. Threat due to disease is one of the major problems in fish farming which leads to poor growth, low survival and less production. Diseases are less prevalent in hatcheries than in nurseries. In improved farming systems, nursery operators have a tendency to overstock fish, which ultimately causes disease. High stocking densities of fry and fingerlings during nursery operation generally increases stress, and subsequently, fish become more susceptible to infectious diseases (Snieszko, 1974) often resulting in mass mortality and reduced product quality, which in turn may cause heavy financial losses for fish farmers (Olcay, 2004). Fry and fingerlings are more susceptible to pathogens than older fish because of their immature immune systems. newline