Disease management in aquaculture industry using probiotics
There has been tremendous growth of aquaculture industry in recent times. Though, such industries enable controlled growth and close monitoring of the growth, they require lot of financial inputs for procurement of good quality seed, maintenance of growth conditions and disease control & management. The lators adds most to the total expenditure of the industry.
Disease management in aquaculture is pretty tricky as aquatic ecosystem is homogenous and once a pathogen is introduced in the environment, it is almost impossible to restrict its spread. Traditionally, antibiotics, hormones and some salt compounds have been used to prevent; rather, treat the diseases. However, this adds exorbitantly to the total expenditure in the overall process resulting in increased product cost. Probiotics are are easiest and cheapest way to overcome this problem.
Probiotic is alive microbial feed supplement which beneficially affects the intestinal health. Unlike, birds and terrestrial animals, lactic acid bacteria are subdominant in the gut of aquatic animals Aquatics probiotics mainly consists of Bacillus sp, Enterococcus sp, Carnobacterium sp & few yeast species. They can be easily isolated from gut of healthy fishes and shrimps. Commercially available products are usually combination of these organisms along with few nutrients. These apply multiple approaches in disease management using principles of antagonism, competitive exclusion, improving immunity, and as an effect of its antibacterial and antiviral activity.
As probiotics are added to the water periodically, there is increase in good microorganisms present in the immediate environment of aquatic species. These probiotic bacteria adhere to the wall of intestinal and improves its health by secretion of metabolites. This ultimately improves nutrient absorption in the intestine and it has also been reported that it results in increased body mass and relatively increased protein content. Probiotics when in aquatic system also release certain metabolites in the surrounding which have bactericidal, bacteristatic and even antiviral properties. These metabolites act as a barrier against the proliferation of opportunistic pathogens.
Improved water quality is one of the most understated benefit of use of probiotics; especially Bacillus sp. The rationale is that gram-positive bacteria are better converters of organic matter back to CO2 than gram-negative bacteria. During the production cycle, high levels of gram-positive bacteria can be minimize the buildup of dissolved and particulate organic carbon, resulting in improved water quality.