These microorganisms have an antimicrobial effect through modifying the intestinal micro biota, secreting antibacterial substances (bacteriocins and organic acids), competing with pathogens to prevent their adhesion to the intestine, competing for nutrients necessary for pathogen survival, and producing an antitoxin effect. Probiotics are also capable of modulating the immune system. Because of this, when provided at certain concentration and viability, probiotics favourably affect host health. In fact, terms such as “friendly bacteria,” “friendly,” or “healthy” are commonly used to describe probiotics.

Probiotics can improve the digestibility of nutrients, increase tolerance to stress, and encourage reproduction Moreover, under these conditions of intensive production, aquatic species are subjected to high-stress conditions, increasing the incidence of diseases and causing a decrease in productivity. (i) modify the host‐associated or ambient microbial community, (ii) improve the use of feed or enhances its nutritional value, enhancing the response of the host towards diseases, or (iii) improve the quality of its ambient environment.

Details : 

Some bacterial species produce a wide range of antagonistic and antibiotic compounds that can be valuable as probiotics. Probiotics are used as an alternative to the prophylactic use of antibiotics. They produce antibiotic compounds to compete for nutrients and sites Probiotics produced sufficient organic acid, along with an associated drop in pH, to antagonize many pathogenic bacteria). Bacillus licheniformis and B. pumilus showed antibacterial activity, tolerated low pH and high bile concentrations). Lactobacillus spp. produced various compounds viz., organic acids, diacetyl, hydro peroxide and bactericidal proteins. These compounds activated the immune systems of animals, and rendered them more resistant to infections by viruses, bacteria, fungi and parasites, or inhibited the bacterial pathogens in aquaculture systems. Bacillus licheniformis CPQBA showed in vitro inhibitory characteristics against Vibrio alginolytic us in white leg prawns. Probiotics exhibited antagonism against pathogens and antiviral effects

Features :

• Antiviral effects
• Elimination of Pathogens by Competition for nutrients
• Elimination of Pathogens by Competition for site attachment
• Digestion enhancement by secretion of Enzymes
• Improvement of quality of Feed Intake by enriching the same with Amino Acids,
• degrading Toxins, improving the palatability etc.
• Modulation of non-specific immune responses
• Production of antimicrobial compounds
• Water quality improvement like pH, Hardness, Turbidity, Heavy Metals, Obnoxious
• gases
• Acetobacter Xylinum Produces Acetic Acid and Nucleotides
• Activated Carbon present binds the Harmful Gases and also traps Toxins and Virus

Benefits : 

Growth Promoter

Probiotics have been used in aquaculture to increase the growth of cultivated species. Several studies have shown that the bacteria of the genus Bacillus spp. secrete exoenzymes (proteases, lipases and carbohydrases) that can help improve digestion and nutrient absorption increase, resulting in better use of food and growth

Bacteria of the genus Bacillus spp. Secrete exoenzymes(proteases, lipases and carbohydrases) that can help improve digestion and nutrient absorption increase, resulting in better use of food and animal growth.

Inhibition of Pathogens

There is a tendency for preventing diseases rather than treating them. Thus, the use of probiotics is a viable alternative for the inhibition of pathogens and disease control in aquaculture species.

Probiotic microorganisms have the ability to release chemical substances with bactericidal or bacteriostatic effect on pathogenic bacteria that are in the intestine of the host, thus constituting a barrier against the proliferation of opportunistic pathogens.

Improvement in Nutrient Digestion

Probiotics have a beneficial effect on the digestive processes of aquatic animals because probiotic strains synthesize extracellular enzymes such as proteases, amylases, and lipases as well as provide growth factors such as vitamins, fatty acids, and amino acids. Therefore, nutrients are absorbed more efficiently when the feed is supplemented with probiotics.

Improvement of Water Quality

By maintaining high levels of probiotics in production ponds, fish farmers can minimize the accumulation of dissolved and particulate organic carbon during the growing season. In addition, this can balance the production of phytoplankton.

Immune system

In relation to farmed shrimp, bacterial diseases are considered as the largest cause of mortality in larvae.The administration of a mixture of bacteria (Bacillus spp. and Vibrio spp.) positively influenced on survival and had protective effect against Vibrio harveyi and the white spot syndrome virus (WSSV) This is due to stimulation of the immune system, by increasing phagocytosis and antibacterial activity.

The administration of a commercial probiotic for the larvae of Marsupenaeus japonicus resulted in increased survival (97%) being significantly higher than the control treatment

Thus, the use of Bacillus coagulans SC8168 as probiotic for post larvae of Litopenaeus vannamei resulted in higher survival. In a study with tiger shrimp (Penaeus monodon), the inoculation of Bacillus S11, a saprophyte strain, resulted in higher survival of postlarvae challenged by a luminescent pathogenic bacterial culture

Bacillus subtilis and Lactobacillus plantarum for Litopenaeus vannamei Pediococcus acidilactici to Litopenaeus stylirostris and Bacillus NL110 and Vibrio NE17 for Macrobrachium rosenberguii also prove to be effective in improving the immune system of these animals.

Stress Tolerance

Aquaculture practices demand intensive productions in shorter times, causing stress in crop species.The results obtained raise the possibility of preparing the fish in advance with probiotic treatment, for conventional aquacultures practices that create stress in animals, such as transport, change in water temperature, and periodic manipulations