Application & Benefits
of Probiotic in Aquaculture
The word Probiotic was first introduced by to describe “substances
secreted by one microorganism that stimulate the growth of another”. The name Probiotic
comes from the Greek “pro bios” which means “for life”.
In the field of aquaculture, the concept of Probiotic should be
defined taking into account other influencing factors that differentiate it
from terrestrial Probiotics.
Extend this definition as “a living microbial complement that has a
beneficial effect in the host or environment, ensuring a better utilization of
the feed or improving the nutritional value, improving the host’s response against
a disease, or by improving the quality of its environment.
1. Pond treatment
2. Water treatment
3. Feed additive
Reduction in Capital outlay:
1. Reduction in chemical input
2. Better disease control.
3. Feed cost reduction.
Increase in yield:
Size and numbers.
Improvement in quality:
1. Better shine.
2. No earthy smell.
3. Better shelf life.
Benefits:
1. Reduces the capital
outlay drastically.
2. Facilitates the culture
of fish and prawns without chemicals.
3. It reduces the quantity
of sludge produced.
4. It eliminates Ammonia,
Methane and Hydrogen sulphide which are
common in fish/prawn
cultivation.
5. It helps to keep water
clean and hence does not require repeated
Changing.
6. Helps in suppressing
algal colonies from bodies of fish/prawns, thus
giving better growth.
7. Fish and prawns produced
are of higher quality and quantity.
8. Feed conversion ratio
(FCR) improves
9. Mortality
of fish and prawns can be reduced significantly.
Overall beneficial effects of Probiotic in
aquaculture. Green arrow indicates additive effects. Red lines indicate
inhibitory effect.
Modes of actions
Colonization capacity
Antagonistic
activity
Enhance
immune responses
Elevate
health status and disease resistance
Improve
water quality
Improve
growth and survival rate
1. Competition for space
Many of the pathogenic bacteria require
attachment to the mucosal layer of the host gastrointestinal tract to initiate
the development of a disease.
An
important mechanism of action in probiotic bacteria is competition for adhesion
sites, also known as ‘competitive exclusion’. The ability of bacteria to
colonize the gut and adhere to the epithelial surface and consequently
interfere with the adhesion of pathogens is a desirable criterion in the selection
of probiotics..
2. Production of inhibitory substances
Probiotic bacteria produce substances with
bactericidal or bacteriostatic effects on other microbial populations such as bacteriocins, hydrogen peroxide, siderophores,
lysozymes, proteases, among many others.
2.1. Antibacterial activity
2.2. Antiviral activity
2.3. Antifungal activity
3. Competition for chemicals or available energy
Probiotic group lactic acid bacteria,
consume the nutrients that are essential for the growth of a number of pathogens.
4. Improving the water quality
Application of Gram-positive bacteria,
Probiotic bacteria possess significant
algicidal effect as well particularly on several species of microalgae,
Probiotics are beneficial as they can
increase microbial species’ composition in the water and modify its quality,
The temperature, pH, dissolved oxygen, NH3 and H2S in rearing water were found to be of higher quality when
probiotics were added, hence maintaining a positively healthy environment for
shrimp and prawn larval in green water system.
5. Nutrients and enzymatic contribution
Some microorganisms have a positive effect
in the digestive processes of aquatic animals.
Probiotics, especially from Bacteroides and Clostridium sp., are
capable of supplying vitamins, fatty acids and essential amino acids to the host.
Gnotobiotic oyster larvae (Crassostrea gigas), fed with auxenic algae (Isochrysis galbana) supplemented with a bacterial strain CA2, showed not only
improved growth performance but efficient nutrient utilization as well.
6. Interference of quorum sensing
Quorum sensing (QS) is defined as the
regulation of gene expression in response to fluctuations in cell-population
density. Many bacteria are using this system to communicate and regulate a
diverse array of physiological activities.
7. Immunomodulation
7.1. Fish
Probiotics by stimulation of immune system
of hosts, including the stimulation of pro-inflammatory cytokines on the
activity of immune cells, increasing the phagocytic activity of leucocytes,, increasing the levels of antibodies, acid
phosphatase, lysozymes, complement, cytokines, IL-10 and transforming growth factor, and antimicrobial peptides, and also, by improving the intestinal microbial
balance, inhibiting the colonization of fish pathogens in the digestive tract,
producing of inhibitory compounds such as bacteriocins, sideropheres,
lysozymes, proteases, hydrogen peroxides, increasing the digestive enzymes activity, and by producing of fatty acids, vitamins, and essential amino acids that are useful for lactic
acid bacteria could improve the growth performance,
immune system and increased resistance on common pathogens in fish.
7.2. Shrimp
Use of probiotics in different species of
shrimps has improved the innate immunity (natural or non-specific immunity).
7.3. Immunomodulation of
the gut immune system
The immune system of the gut is related to
gut-associated lymphoid tissue (GALT) and there are some differences in respect of Peyer's
patches, secretory IgA and antigen-transporting M cells in the intestine of
piscine and mammal gut immune system.
7.4. Amelioration of the
effects of stress
Stress might be regarded as a physical or
chemical agent causing reactions that may result in disease and death. Any
change in water parameters may have a side effect on the physiological and
behavioral aspect of aquatic animals. Many harmful agents for fish exist in
their environment like the water, soil, air or even their own body.
Conclusion and future perspectives
Use of probiotics is an effective alternative
sustainable source of beneficial microbes with bactericidal or bacteriostatic
effect on pathogenic bacteria, with anti-bacterial, anti-viral and anti-fungal
activity, immunomodulatory capabilities of promoting health and welfare to
improve the growth performance, augment the immune system, disruption of QS as
a new anti-infective strategy, ameliorate the harmful effects of oxidative
stress factors and increased resistance for common pathogens in fishes for
controlling potential fish pathogens.
An interactive approach among academicians, scientists,
producers and fish sector owners is required to focus and explore the specific
aspects of bacteria–host interactions conferring the possible favorable changes
in diverse immune responses elicited by different bacterial strains in order to
propose clinically effective, bacteria-based strategies to promote the health,
production and economic growth of the aquaculture industry.
Probiotic formulation should be viable on large scale
at low operational cost. They should not be treated as ‘elixir of life’, rather
they should be used as supplement to balance the diet to avail and maintain the
sound health free of infections and disease-causing microorganisms.
The present review has summarized the importance of
potential probiotics and their future perspectives in fastest growing food
production sector of aquaculture industry.
Conclusion and future perspectives
Use of probiotics is an effective alternative
sustainable source of beneficial microbes with bactericidal or bacteriostatic
effect on pathogenic bacteria, with anti-bacterial, anti-viral and anti-fungal
activity, immunomodulatory capabilities of promoting health and welfare to
improve the growth performance, augment the immune system, disruption of QS as
a new anti-infective strategy, ameliorate the harmful effects of oxidative
stress factors and increased resistance for common pathogens in fishes for
controlling potential fish pathogens.
An interactive approach among academicians, scientists,
producers and fish sector owners is required to focus and explore the specific
aspects of bacteria–host interactions conferring the possible favorable changes
in diverse immune responses elicited by different bacterial strains in order to
propose clinically effective, bacteria-based strategies to promote the health,
production and economic growth of the aquaculture industry.
Probiotic formulation should be viable on large scale
at low operational cost. They should not be treated as ‘elixir of life’, rather
they should be used as supplement to balance the diet to avail and maintain the
sound health free of infections and disease-causing microorganisms.
The present review has summarized the importance of
potential probiotics and their future perspectives in fastest growing food
production sector of aquaculture industry.
