Nutrition of shrimp is an important consideration in health management of cultured vannamei shrimp. The extensive to semi-intensive and intensive farming of shrimp demands nutritionally complete feeds for successful culture. The use of nutritionally inadequate feeds for shrimps can result in reduced growth, less production, more stress, low survivals, nutritional deficiency syndromes, mortality, infectious diseases etc.
The uses of a wide variety of natural compounds are capable to modulate the sustainable gut microflora in shrimps towards a favorable composition such as probiotics, organic acids, yeast extracts and phytobiotics. Among the synergistic effects of these compounds, phytobiotics play major role to enhance the various functions in shrimps.
To improve the health and growth of commercially important aquatic species are major concern for successful of culture. It is necessary to improve the economics of shrimp production by improving the efficiency of feeds and by lowering the cost of feeds. Recently plant extracts have been used as feed additive with good results in the control of bacterial and viral diseases in aquaculture.
Phytobiotics can be defined as plant derived products added to feed in order to improve the health performance of animal. The phytobiotics have a wide variety of properties such as antioxidant, antimicrobial, anticarcinogenic, analgesic, insecticidal, antiparasitic, anticoccidial, growth promoters, appetite enhancement, stimulant of secretion of bile and digestive enzyme activity, immunity enhancer etc.
The main herbal plant and their extracts are used widely as multiple therapeutic properties in aquaculture. Phytobiotics produce active substances like Sabinene, Ammameldehyde, Eugenol, Cinook, Capsaicin, Zingerole, Piperine, Allicin, Cineole, Thymol, Menthol, Azadirachtin, salanin numbin etc.
Importance of Phytobiotic in Multifunctional Activities of Shrimp
Role of Phytobiotic in Gut Micro Flora of shrimp
In aquaculture, the gut microbiota has the important role in the optimal functioning of the digestive system of shrimp. Shrimp are actively “grazing” on the bottom substrate, and therefore highly exposed to exchanges of microflora between the environment and the digestive system. This increases the risk for the proliferation of an unfavorable gut microflora or frequent destabilization of the microflora, which can affect the optimal functioning of the digestive system.
Maintaining a stable and favorable gut microflora is crucial importance to minimize the impact of diseases and to optimize digestive efficiency in shrimp for resulting in improved survival and productivity. Promoting a stable and well balanced gut microbiota in early life stages is a key factor for maximizing production yield and profitability in the grow-out operation. Furthermore, the digestive system of shrimp is the main entry port for bacterial, viral and parasitic infections which remain a major risk for the profitability of aquaculture production.
Stimulation of feed intake and digestive secretions
Herbs develop their initial activity in the feed as flavour and influence eating patterns. It helps the secretion of digestive fluids and total feed intake. Stimulation of digestive secretions including digestive enzymes, bile and mucus is often considered to be one of the important actions of phytobiotics.
Various types of phytobiotic feed additives enhance the digestibility and utilization efficiency of nutrients including exogenous enzymes and stimulators of enzyme secretion. These compounds help in the digestive process by improving absorption, mobilization and transport of nutrients. These act as feeding stimulants which reduce feed or nutrient waste. Phytobiotic feed promotes better feed conversion and protein efficiency in feeding system.
Antimicrobial and Parasitical activities
Phytobiotic acts as most antimicrobial agents and exert their effects by modulating the cellular membrane of microbes. Furthermore, a strong increase in hydrophobicity of the microbial species in the presence of some plant extracts may influence the surface characteristics of microbial cells and thereby affect the virulence properties of the microbes. This may be an important antimicrobial mechanism of some plant extracts. The adhesion of microbes to intestinal mucosal cells is of vital importance for some pathogenic microflora and is strongly influenced by the hydrophobic surface properties of microbial cells. Various essential oil mixtures, which contain natural polyphenolic compounds or flavonoids as major active ingredients, have been identified as potential antimicrobial and antioxidant agents. Thus, phytobiotic feed additive can create a healthier gut microflora, aiding optimum digestion and improving health performance.
Phytobiotics can selectively influence microorganisms through antimicrobial activity or by a favorable stimulation of the eubiosis of the microflora. This leads to better utilization and absorption of nutrients resulting in higher performance. A synergistic blend of phytobiotics is selected for their bacteriostatic and bactericidal properties against pathogenic and potentially pathogenic bacteria in vitro.
Phytobiotics containing gut health promoters with natural antimicrobial activities into the digestive system. Phytobiotics are a key component of any strategy to prevent diseases in aquaculture particularly in the rearing of young stages where opportunistic bacteria are still a major cause of mortality. The effect of a synergistic phytobiotic compound have shown considerable results against bacterial diseases like. Vibiosis, LB, Gill diseases, Gill fouling, White gut, white feces, Vibrio parahaemolyticus (Early Mortality Syndrome, Acute Hepatopancreatic Necrosis Disease, EMS/AHPND). Furthermore, the addition of the phytobiotic product in the diet resulted in consistently lower Vibrio counts in the shrimp's digestive system.
Also, phytobiotic functional feed additive can effect on various parasitical infections in shrimp and prevent external protozoan diseases.
Phytobiotics in hatchery and nursery
Phytobiotics is particularly important in hatchery and nursery stages where feed particles are too small to incorporate additives at the farm and the feeding frequency will affect greatly the duration of the exposure of the gut microbiota to the gut health promoter. Phytobiotics feed additives have combining different action mechanisms as direct bactericide/bacteriostatic properties as well as Quorum Sensing inhibition properties. These properties are most promising to control bacterial diseases caused by opportunistic bacteria such as Vibrio spp.
Gut health modulation is a promising tool to control the count of opportunistic bacteria such as Vibrio spp associated with the gut of hatchery and nursery stages. The inclusion of natural products with bactericidal and quorum quenching activities is an important factor in current biosecurity protocols to prevent the vertical spread of opportunistic bacterial pathogens.
A healthy gut microbiota enhances the overall health status and immune defenses, which may explain the positive effect of gut modulators on reducing the impact of certain endo as well as ectoparasites on productivity in fish.
Stimulation of the immune system
Polysaccharides derived from many plants play an important role in stimulating the growth of immune organs increasing the number and activities of many interdependent cell types such as T, B lympocytes, macrophages and natural killer (NK) cells, and enhancing cellular and humoral immune response.
Some of herbal extracts are well known as a powerful antioxidant. One of the major roles of phyto-antioxidants in aquaculture production is on lipid oxidation. Plant oils containing natural antioxidants contribute to the improved oxidative stability of meat and meat products containing higher levels of polyunsaturated fatty acid.
Natural Growth Promoter
The phytobiotic compounds promote the better growth rate in shrimp and fish.
Herbs are desirable for stimulating digestion and have the highest stimulatory influence particularly on bile secretion and pancreatic enzymes activity. In other way, olfactory feed ingredients enhance growth through their ability to act as feeding enhancers for shrimp to eat more feed than in normal. The herbs act as an alternative for antibiotic growth- promoters in shrimp.
Phytobiotic Compound & Functional Feed Additive “WHITENIL”
The WHITENIL is a natural product in preparation with various phytobiotic compounds: Garlic powder, Selected probiotics, Seaweed extracts, Vitamins & minerals. It is manufactured by M/S International Healthcare Limited, India.
Major advantages of WHITENIL
- Maintains the gut microbial equilibrium
- Maintains the structural integrity of gut
- Reduced impact from bacterial pathogens and parasites in gut
- Improves on survival and productivity
- Improves digestion
- Enhances absorption of nutrients.
- Acts as natural growth promoter in shrimps.
- Optimizes FCR
- Prevents and controls diseases like white gut, white feces syndrome, white muscle etc in shrimp
- Enhances immunity in shrimp body
- Regulate periodical moulting process
- Acts as antioxidant in shrimp.
The trial was executed in the shrimp culture ponds located in Kalagachia areas of Purba Medinapur dist W. Bengal, India during the period March – June 2018. During the trial, two ponds were selected in each areas for study the effect of WHITENIL on health and productivity performances in shrimp as “Control” (without WHITENIL) and Experimental (with use of WHITENIL). The outcome results of both ponds were compared on growth, survivals, production, FCR, diseases infection, etc.
The additive WHITENIL was added to the feed at 10 gm per kg of feed from 1st of stocking days to 60 days of culture and then 5 gm per kg of feed from 60 days to end of culture with using a commercial binder throughout the trial period.
The water spread area of trial ponds are approximately 1000 m2 & 2200m2 /each and having water depth 1.5 mt to 2.0 mt during entire culture period of 115 &120 days. The stocking of Vannamei shrimp post larvae (PL-12) at a density of 100 &75 no per m2 in pond I & pond II respectively. The pond preparation, water management, Feeding, aeration systems & Pond management were followed according to routine protocols of the pond management.
The control pond (whit out WHITENIL) was selected near this area having water spread area 1000m2 with water depth 1.5 mt- 2.0 mt entire culture period. The stocking density was 100 no /m2 of PL12and total culture period was 114 days.
The feed additive WHITENIL was applied twice daily during the morning and evening regularly for 4 days in a week. Production variables at harvest that were compared between treatments included survival, harvested crop yield per ha, feed conversion ratio (FCR), weekly growth and average harvest weight per shrimp.
The high stocking trial ponds showed some interesting trends on growth, production, FCR, survivals and diseases. The supplementation of the gut health modulator resulted in improved values on trial ponds with compared to control pond. It is observed better results on survivals, average body weight, growth, FCR and Production. Also, diseases and infections are very less or not at all in trial ponds whereas some diseases noticed in control pond.
The synergistic phytobiotic product WHITENIL have a greater effects in trial ponds towards prevention and controlling of diseases like Vibriosis, White gut, White feces, Luminous bacteria, External infections, Black gill, etc. The regular and normal moulting was noticed in trial ponds without much soft or loose shell problems. The addition of the phytobiotic product in the diet resulted in consistently lower Vibrio counts in the shrimp’s digestive system compared to the control.
WHITENIL acts as gut modulating additives and capable to protect the shrimp’s gut flora throughout a Vibrio challenge. WHITENIL has confirmed its potential to improve productivity and reduce costs under the various stressful conditions in shrimp culture ponds.