Prepared By; Gokhale Govinda Satish M.F.Sc (Aquaculture)
Introduction
As the human population continues to grow, food production industries such as aquaculture will need to expand as well.
Shrimp farming has become competitive and as such the technology utilized needs to be efficient in all aspects – productivity, productivity, quality, quality, sustainability, sustainability, bio-security and to be in line with market demand.
In order to preserve the environment and the natural resources, this expansion will need to take place in a sustainable way.
Introduction
As the human population continues to grow, food production industries such as aquaculture will need to expand as well.
Shrimp farming has become competitive and as such the technology utilized needs to be efficient in all aspects – productivity, productivity, quality, quality, sustainability, sustainability, bio-security and to be in line with market demand.
In order to preserve the environment and the natural resources, this expansion will need to take place in a sustainable way.
Three Goals….
The prime goal of aquaculture expansion must be to produce more aquaculture products without significantly increasing the usage of the basic natural resources of water and land.
The second goal is to develop sustainable aquaculture systems that will not damage the environment.
The third goal is to build up systems providing an equitable cost/benefit ratio to support su pport economic and social sustainability. sustainability.
All these three prerequisites for sustainable aquaculture development can be met by biofloc technology
Definition:-
The Biofloc is a protein rich macro aggregate of organic material and micro-organisms including diatoms, bacteria, protozoa, algae, fecal fecal pellets, remains of dead organisms organisms and other invertebrates.
Biofloc Technology
Biofloc technology is a technique of enhancing water quality in aquaculture through balancing carbon and nitrogen in the system.
The technology has recently gained attention as a sustainable method to control water quality, with the added value of producing protein rich feed in situ.
The basic technology was developed by Dr. Yoram Avnimelech in Israel and initially implemented commercially in Belize by Belize Aquaculture.
Biofloc technology has become a popular technology in the farming of Pacific white shrimp, Litopenaeus shrimp, Litopenaeus vannamei
Cont…..
It is possible that this microbial protein has a higher availability than feed protein.
The basic requirements for biofloc system operation include high stocking density, high aeration and lined ponds.
A crucial factor in the system is the control of biofloc in ponds during operation. Fish /shrimp are fed with a lot of feed
About 70-80% of it remains in the pond, in the water or the sediment.
Ponds contain a high load of nutrients
The outcome…. What are the outcomes? -We waste Feed/Money (Quite a lot!) - Toxic residues (Sulphides, Ammonia etc) accumulate.
- Fish growth is affected. - Intensification is limited (loose income, not being able to raise production)
- Use industrial RAS (Recycling Aquaculture systems) Quite expensive ) - use biofloc technology.
Basic of BFT in Shrimp Farming 1. High stocking density - over 130 – 150 PL10/m2
2. High aeration – 28 to 32 HP/ha/ PWAs 3. Paddle wheel position in ponds 4. HDPE / Concrete lined ponds 5. Grain (pellet)
High density
6 Molasses 7. Expected production 20 – 25 MT/ha/crop
High aeration
Paddle Wheels position
Pond Operation High Aeration
Siphoning
STAGES FLOC Development stages (vol) in pond Stage 1 : Floc found but cannot measured (subjective) Stage 2 : Floc found in small quantity, < 1.0 ml/litre Stage 3 : Floc found abundance, 1.0 – 5.0 ml/litre Stage 4 : Floc found abundance, 5.1 – 10.0 ml/litre Stage 5 : Floc found abundance, > 10.1 ml/litre
Sampling Method Measuring procedure 1 liter / 2 places/ 15 cm deep/ between 10-12 am
Let it settled for 15-20 minutes
Read density of flocs in cone (ml/l)
‘Floc’ Development Average Floc Development
Floc (ml/L) 14 12 10 8 6 4 2 0 20
30 Floc
40
50
60
70
80
90
100
110
120
130
DOC (days)
Control Biofloc Black gill
Black biofloc
Biofloc- general view at surface
What is BFT? We limit water exchange ► Organic residues accumulate ► We mix and aerate. ► Ideal conditions for bacteria ► Bacteria control water quality. ► Fish eat bacteria
Feed is recycled
Conditions for bacteria There is a lot of available food for bacteria. The pond is loaded with organic residues. ► The pond is fully aerated (needed for proper fish growth).
The pond is well mixed (typically 24 hours a day)
The number of bacteria in such ponds is 10 ⁶ up to 10⁹ Bacteria in one cm3!!!!
The pond becomes a biotechnological industry – Biofloc Technology
Manipulating bateria Normally, there is enough nitrogen in ponds for new cell production. ► By adding carbohydrates( eg Starch, flour, molasses, cassawa etc) to the pond, heterotrophic bacterial growth is stimulated and nitrogen uptake through the production of microbial proteins takes place.
Then, there is a need for nitrogen .
If carbon and nitrogen are well balanced in the solution, ammonium in addition to organic nitrogenous waste will be converted into bacterial biomass.
► The way to do it: Keep C/N ratio higher than 10
The bacteria now take the nitrogen from the water and control water quality
Cont…..
This promoted nitrogen uptake by bacterial growth decreases the ammonium concentration more rapidly than nitrification.
Immobilization of ammonium by heterotrophic bacteria occurs much more rapidly because the growth rate and microbial biomass yield per unit substrate of heterotrophs are a factor 10 higher than that of nitrifying bacteria.
Can we feed fish or shrimp with bacteria? Bacteria are very small.
Luckily, when we have a dense culture,
They tend to form bioflocs, containing bacteria, other organisms and organic particles.
Mechanism of floc formation
The flocculation of microbial communities is a complex process.
Within the floc's matrix, a combination of physical, chemical and biological phenomena is operating.
The exact mechanisms and the methods microbiological flocs remain largely unknown.
The main constituents that can be found within the floc matrix are the extracellular polymeric substances.
These structures form a matrix that encapsulates the microbial cells, and play a major role in binding the floc components together.
to
engineer
Cont
…..
They are typically made up out of polysaccharides, protein, humic compounds, nucleic acids and lipids.
They are produced as slime or capsule layers under various nutritional conditions but particularly in case of limitation by nutrients like e.g. nitrogen.
Factors influencing floc formation and floc structure in bio-flocs technology
Mixing intensity
DO
Organic carbon source
Organic loading rate
Temperature
pH
APPLICATION OF BIOFLOC TECHNOLOGY IN AQUACULTURE
Nursery
phase is defined as an intermediate step between hatchery-reared early postlarvae and grow-out phase.
Such phase presents several benefits such as optimization of farm land, increase in survival and enhanced growth performance in grow-out ponds.
BFT has been applied successfully in nursery phase in different shrimp species such as L.vannamei , P. monodon , F. paulensis , F. brasiliensis and F. setiferus.
Better nutrition by continuous consumption of biofloc
The growth enhancement of L. vannamei post larvae reared in nursery BFT is related to a better nutrition by continuous consumption of biofloc, which might positively influence growout performance of L vannamei .
Enhance growth performance
-It was observed that presence of bioflocs resulted in increases of 50% in weight and almost 80% in final biomass in F. paulensis early postlarval stage when compared to conventional clear-water system.
Increased the survibility rate
reported survival rates of L vannamei in BFT nursery pond range from 55.9% to 100% and 97% to100%, respectively.
Maintain favorable water quality and enhance production.
the addition of substrates in BFT systems increased growth and further enhanced production, while also contributing to more favourable water quality conditions. According to the same study, growth and survival was not affected by stocking density (2500 vs 5000 PL/m2), therefore greater production outputs were achieved at the higher density. The F. brasiliensis postlarvae grow similarly with or without pelletized feed in biofloc conditions during 30-d of nursery phase, which was 40% more than conventional clear-water continuous exchange system. ► Decrease FCR and reducing cost in feed
Grow out
In grow-out, BFT has been also shown nutritional and zoo technical benefits.
It was estimated that more than 29% of the daily food intake of L. vannamei consisted of microbial flocs, decreasing FCR and reducing costs in feed.
The reference showed that juveniles of L. vannamei fed with 35% CP pelletized feed grew significantly better in biofloc conditions as compared to clear-water conditions.
It was showed that controlling the concentration of particles in super-intensive shrimp culture systems can significantly improve shrimp production and water quality
Also, the same authors demonstrated that environmentally friendly plant-based diet can produce results comparable to a fish-based feed in BFT conditions.
It was evaluated the stocking density in a 120d of L. vannamei BFT culture, reporting consistent survival of 92, 81 and 75% with 150, 300 and 450 shrimp/m2, respectively.
Moreover, the study performed in a heterotrophic-based condition detected no significant difference in FCR when feeding L. vannamei 30% and 45% CP diets and 39% and 43% CP diets, respectively.
floc biomass might provide a complete source of cellular nutrition as well as various bioactive compounds even at high density.
It is not known exactly how microbial flocs enhance growth.
Is well known that protein, peptides and amino acids participate fully in synthesis of new membranes, somatic growth and immune function and biofloc can potentially provide such ingredients.
Application in Breeding
The BFT has been successfully applied for grow-out, but little is known about biofloc benefits on breeding.
Biofloc in a form of rich-lipid-protein source could be utilized for first stages of broodstock's gonads formation and ovary development.
Furthermore, production of brood stock in BFT could be located in small areas close to hatchery facilities, preventing spread of diseases caused by shrimp transportation.
BFT could enhance spawning performance as compared to the conventional pond and tank-reared system, respectively (i.e. high number of eggs per spawn and high spawning activity
As an alternative for continuous in situ nutrition during the whole life-cycle, breeders raised in BFT limited or zero water exchange system are nutritional benefited by the natural productivity (biofloc) available 24 hours per day.
better
control of water quality parameters and continuous availability of food (biofloc) in a form of fatty acids protected against oxidation, vitamins, phospholipids and highly diverse “native protein”, rather than conventional systems which “young” breeders are often limited to pelletized feed.
The continuous availability of nutrients could promote high nutrient storage in hepatopancreas, transferred to hemolymph and directed to ovary, resulting in a better sexual tissue formation and reproduction activity.
Excess of particulate organic matter covered breeder’s gills and could limit oxygen exchange, might resulting in mortalities
Application in animal food industry
The cost of diets in several animal cultures is predominantly due to the cost of protein component.
Fishmeal is prime raw material as a component of aquaculture feed.
The quality attributed to fishmeal includes high palatability, high content of digestible protein, highly unsaturated fatty acids (HUFA) and minerals.
Recently the aquaculture industry has been facing some important limitation i.e increasing price of fish meal
pressure on natural stock (overfishing)
Increasing price of fish meal competition with animal cultures (swine and poultry) and differences in quality.
Aquaculture industry needs to investigate alternative source of proteins to replace less sustainable ones
The microbial particles can provide important nutrients such as protein , lipids , amino acids and fatty acids.
Biofloc act as raw material to produce “biofloc meal.
Biofloc meal (also called “single-celled” protein), added to compounded feed is currently focus of intensive research in nutrition fields.
However, to produce this protein ingredient some processes are required such as drying, milling and storage.
In this context, nutritional characteristics could be affected (by i.e. temperature during drying)
Nutritional
composition of biofloc differs according to environmental condition, carbon source applied, TSS level, salinity, stocking density, light intensity, phytoplankton and bacterial communities and ratio, etc
Crude protein (%)
Carbohydr ates (%)
Lipids (%)
Crude fiber (%)
Ash (%)
Reference
43.0
-
12.5
-
26.5
McIntosh D. et all 2000
31.2
-
2.6
-
28.2
Tacon AGJ et all 2002
12.0-42.0
-
2.0-2.8
-
22.0-46.0
Soares R et all 2004
31.1
23.6
0.5
-
44.8
Wasielesky W.et all 2006
26.0-41.9
-
1.2-2.3
-
18.3-40.7
Ju ZY et all 2008
30.4
-
1.9
12.4
38.9
Ju ZY et all 2008
49.0
36.4
1.13
12.6
13.4
Kuhn DD et all 2009
38.8
25.3
<0.1
16.2
24.7
Kuhn DD et all 2010
28.8-43.1
-
2.1-3.6
8.7-10.4
22.1-42.9
Maicá PF,et all 2012
The use of bioflocs as a bio-control measure
Intensive aquaculture of crustaceans is one of the fastestgrowing sectors in aquaculture production.
Despite its huge success, shrimp culture is facing severel outbreaks of infectious diseases, which have caused significant economic losses.
Due to the haphazard mishandling of antibiotics in aquaculture, pathogenic bacteria are now becoming resistant to numerous antibiotics and as a result, antibiotics are no longer effective in treating bacterial disease.
The disruption of quorum sensing, bacterial cell-to-cell communication with small signal molecules has been proposed as a new strategy to control bacterial infections in aquaculture
As this cell-to-cell communication mechanism regulates the expression of virulence factors.
recently found that bioflocs grown on glycerol were able to protect gnotobiotic brine shrimp (Artemia franciscana) against pathogenic Vibrio harveyi, and that the beneficial effect was likely due to interference with the pathogen's quorum sensing system
Another interesting feature of bioflocs to further investigate with respect to biocontrol effects is the capability to accumulate the bacterial storage compound poly-β-hydroxybutyrate (PHB).
PHB and PHB accumulating bacteria have been shown to protect different aquaculture animals from bacterial infections.
PHB-accumulating bacteria that are present in bioflocs has PHB levels of between 0.5 and 18% of the dry matter.
Bioflocs might also contain immunostimulatory compounds since biofloc technology deals with bacteria and bacterial products
Use of biofloc in aquaponics
Aquaponics is a sustainable food production system that combines a traditional aquaculture with hydroponics in a symbiotic environment.
Nowadays,
BFT have been successfully applied in aquaponics. The presence of rich-biota (microorganisms of biofloc) and a variety of nutrients such as micro and macronutrients originated from un-eaten or non-digested feed seems to contribute in plant nutrition.
A well known example of biofloc and aquaponics interaction was also developed by UVI. However, the application of BFT in aquaponics needs particular attention, mainly on management of solid levels in water.
High concentration of solids may cause excessive adhesion of microorganism on plants roots (biofilm), causing its damage, lowering oxygenation and poor growth. Filtering and settling devices are often needed
Aquaponics system a t University of Virgin Islands
Commercial Interest
Commercial interest in biofloc technology is threefold, for bioflocs provide high productivity, low feedconversion ratios (FCRs) and a stable culture environment.
Also, with emerging viral problems and rising costs for energy, biofloc technology appears to be an answer for sustainable production at lower cost.
The technology has not only been applied at commercial shrimp grow-out farms, but also in super-intensive raceways to produce more than 9 kg shrimp/m3.
The raceway applications have supported nursery and grow-out to shrimp broodstock rearing and selection of family lines.
Presently, a number of studies by major universities and private companies are using biofloc as a protein source in shrimp and fish feeds
BIOFLOC TECHNOLOGY – WORLD WIDE
Belize, Central America Biofloc system culture
Belize Aqua Ltd – A view
BELIZE SHRIMP FARM (McIntosh, 2000b&c) L. vannamei Mexican strain Pond size 1.6 hectare Pond type Fully HDPE lined Aeration input 48 HP of PWA System Heterotrophic zero water exchange Production 13,500 kg/ha/crop Carrying capacity 550 kg shrimp/HP of PWAs
Malaysia Biofloc System initiated – on going Well designed farm layout
BAB Semi biofloc (8-9 MT /0.8ha pond -Target)
Seawater Intake – 2.6 km offshore
Biofloc
Shrimp Farms in Indonesia & Malaysia Blue Archipelago Malaysia
Global Medan Indonesia
Bali, Indonesia
CPB Lampung, Indonesia
Potential of BFT – PERU Lined and covered
Piura - Intensive with freshwater covered
Piura -Inside covered pond Grain
Tumbes-Extensive with SW
Potential for BFT – GUATEMALA Lined with high energy input Pasca Shrimp Farm 1
Potential for BFT – CHINA Lined, covered & high energy input
Covered ponds
Inside covered & lined ponds
Covered ponds
Inside covered & lined ponds
Development of BFT (Productivity) NT- Advised by long visits
NT – Managed at site NT – Advised by short visits
YA -Advised by email RM- Managed at site
According to Shrimp News International (2006) No one knows how many shrimp farms are employing the bio-floc technology. The best examples of the of farms that have implemented the new technology are: 1. Belize Aquaculture, Ltd., in Belize. 2. OceanBoy Farms in Florida, USA, and 3. PT Central Pertiwi Bahari in Indonesia.
Advantages/ Disadvantages Advantages
1. Bio-security very good (from water) – to date WSSV negative using the system. 2. Zero water exchange – less than 100% exchange for whole culture period. 3. Production (Carrying capacity): 5-10% better than normal system 4. Shrimp size bigger by about 2.0 g than normal system 5. FCR low – between 1.0 to 1.3 (without GP) 6. Production cost lower by around 15-20 %.
Disadvantages 1. High energy input – paddlewheels 28HP/ha. 2. Power failure critical – maximum one hour at any time (better zero hour failure) 3. Full HDPE lined ponds – minimum semi-HDPE lined 4. Technology similar but more advance – need to train technicians
