Biofloc fish farming
Today, we discuss the topic of Biofloc Fish Farming Advantages; Disadvantages, and Training Centers in India.
What is Biofloc Technology? Biofloc technology (BFT) is a relatively new and potentially revolutionary organism that is especially productive for aquaculture. BFT is a sustainable and environmentally-friendly process of aquaculture that controls water quality and harmful pathogens along with providing value-added creation of the microbial protein feed for the aquatic farm structure. What is Biofloc fish farming? High-density rearing of fish generally requires some waste management infrastructure. At its core, Biofloc system is a waste treatment system. Biofloc systems were developed to prevent the introduction of disease to a farm from incoming water.
Biofloc systems were developed to increase environmental control over production. In places where water is scarce or land is expensive, more intensive forms of aquaculture should be practiced for cost-effective production. There are strong economic incentives for an aquaculture business to be more capable with production inputs, particularly the most costly (feed) and most limiting (water or land).
The nutritional quality of Biofloc system of cultured animals is good but rather variable. The dry-weight protein content of Biofloc ranges from 25 – 50 percent, with most estimates between 30 and 45 percent. Fat content ranges from 0.5 – 15 percent, with most estimates between 1 and 5 percent. There are conflicting reports about the adequacy of Bioflocs to give the often limiting amino acids methionine and lysine. Bioflocs are good sources of vitamins and minerals, particularly phosphorus. Bioflocs may have probiotic effects.
What Biofloc systems do?:
Bioflocs provide two critical services that are treating wastes from feeding and providing nutrition from floc consumption. Biofloc systems can work with low water exchange rates (0.5 to 1 percent per day). This long water residence time allows the development of a dense and active Biofloc technology profitability and business sustainability. However, the value of flocs in nutrition is limited at the highest levels of production intensity since the contribution of feed to the growth of cultured animals is overwhelming.
Read: RAS Fish Farming Techniques.
Composition and nutritional value of Biofloc:
Biofloc is a heterogeneous aggregate of suspended particles and selection of microorganisms associated with extracellular polymeric substances. Biofloc is composed of microorganisms such as bacteria, algae, fungi, invertebrates, and detritus, etc. It is a protein-rich live feed created as a result of the conversion of unused feed and excreta into a natural food in a culture system on exposure to sunlight. Each floc is held jointly in a loose matrix of mucus that is secreted by bacteria and bound by filamentous microorganisms or electrostatic attraction. Large flocs are seen with the naked eye, but most of them are microscopic. Floc size range from 50 to 200 microns.
A good nutritional value is originated in Biofloc. The dry weight protein ranges from 25 to 50 percent, fat ranges 0.5 to 15 percent. It is a good source of vitamins and minerals, mainly phosphorous. It has an effect similar to probiotics. The dried Biofloc is planned as an ingredient to replace the fishmeal or soybean in the feed. The nutritional quality is good; however, limited qualities are available. Also, the cost-effectiveness of producing and drying Biofloc solids at a commercial scale is a challenge. How does Biofloc system work? The main component of Biofloc is heterotrophic bacteria. The function of the Biofloc is to reduce the nitrogenous metabolic waste (ammonia, nitrite) produced by fish feeding and production. Ammonia consumed by heterotrophic bacteria becomes protein, which can then be consumed by fish and converted into growth.
Biofloc system in fishes:
The food and agriculture organization (FAO) recently predicted that the current level of precipitate consumption of aquatic foods is necessary to uphold due to the increasing global population. For this, the world would need an additional 23 million tonnes of seafood by 2020. It can be expected that aquaculture can meet the demand for this additional seafood production, which is estimated to contribute around 93.2 million metric tonnes by 2030. In order to increase aquaculture yields, the country needs additional resources.
In addition to the problem of finding the resources, there are several other factors such as increasing operational costs, the high cost of land for culture, the high cost of feed ingredients or commercial feed, creation and disposal of waste sludge, discharge of effluent from aquaculture farms hinders the economic success or viability of commercial aquaculture.
In aquaculture, the major cost during the entire production cycle has been contributed by feeding of fish. Similarly, about 60 to 70% of the variable cost involved in the operation was attributed to feeding alone which in turn reduced the farmer’s profit. The principal factor which affects the development and expansion of the aquaculture industry is nothing but the cost of feed. Another main issue raised in today’s situation is water scarcity which severely ruins food security and hampers the development of the sector.
Almost 70 percent of all water removal was accounted for from agriculture, which became a significant cause of water scarcity. It was reported that approximately 2,000 to 5,000 liters of water is required to generate the food consumed by one person daily. All these issues can be overcome by increasing the fish biomass per unit area and reducing the use of expensive feed ingredients or high protein feeds.
When fish fed with very high protein diets, the nitrogen (approximately 70 %) present in protein is discharged as waste into the surrounding culture water. This waste nitrogen can be incorporated into a functional form by the culture species in Biofloc system. By using Biofloc system as a cultural system, two problems can be solved at once, i.e., reduction of protein inputs and elimination of water exchange to maintain water quality. Microbial floc not only helps to develop the environmental control over production by reducing the nitrogen and ammonia from the culture water but also act as nutrient trappers who can be helpful in the feed management thereby reducing the feed cost. They are helpful in enhancing biosecurity and health. Biofloc technology is achievable by using different types of organic carbon. Utilization of low-value carbohydrates for the production of Biofloc can further decrease the cost of production in aquaculture. The use of Biofloc system in commercial aquaculture is insufficient, and this technique is not yet fully standardized.
Suitable culture species
An essential factor in designing a Biofloc system is the species to be cultured. Biofloc systems work best with species that are able to derive some nutritional advantage from the direct consumption of floc. Biofloc systems are most suitable for species that can tolerate high solids concentration in water and are generally tolerant of poor water quality. Species such as fish and tilapia have physiological adaptations that allow them to consume Biofloc and digest microbial protein, thereby taking benefit of Biofloc as a food resource. Nearly all Biofloc systems are used to grow fish, tilapia. Catfish and hybrid striped bass are examples of fish that are not good candidates for Biofloc technologies because they do not tolerate water with high solids concentrations and they do not have adaptations to clean solids from water.
Growth performance Biofloc fishes
The growth performance of fishes, length, and weight were measured at an interval of 15 days by weighing 10 fishes from each treatment replicates randomly. Fishes were starved for an overnight proceeding to sampling. The total body length of the fish was measured using a measurement scale, through an electronic weighing balance was used to measure the body weight of the fish. Different type growth parameters like specific growth rate (SGR), percentage weight gain (PWG), feed conversion ratio (FCR), the protein efficiency ratio (PER), biomass and survival were measured using the following formulas.
Specific Growth Rate (SGR) (%) = (Loge Final Weight –Loge Initial Weight) / (Number of Days) X 100.
Percentage weight Gain (PWG) (%) = (Final Weight – Initial Weight) / (Initial Weight) X 100.
FCR = Feed given (dry weight) / Body weight gain (wet weight).
PER = Body weight gain (wet weight) / crude protein fed.
Survival (%) = (Total No. of Harvested Animal) / (Total No. of Stocked Animal) X 100.
Benefits of Biofloc culture system
- Biofloc is an eco-friendly culture system.
- Biofloc system reduces environmental impact.
- Efficiently improves land and water use efficiency.
- Limited or zero water exchange.
- Productivity will be high (It enhances survival rate, growth performance, feed conversion in the culture systems of fish).
- Higher biosecurity.
- Reduces water pollution and the risk of introduction and spread of pathogens.
- Cost-effective feed production.
- It reduces the use of protein-rich feed and the cost of standard feed.
- Biofloc system reduces the pressure on capture fisheries that means the use of cheaper food fish and trash fish for fish feed formulation.
Disadvantages of Biofloc system
- Increased energy requirement for mixing and aeration.
- Reduced reaction time because water respiration rates are elevated.
- Start-up period required.
- Alkalinity supplementation required.
- Increased pollution potential from nitrate accumulation.
- Inconsistent and seasonal performance for sunlight-exposed systems.
Biofloc Fish Farming Training
- CIBA- Central Institute of Brackishwater Aquaculture
75 Santhome High Road, RA Puram,
Chennai 600028, Tamil Nadu
- CIFA-Central Institute of Freshwater Aquaculture
Bhubaneswar, Odisha, India
Phone: 91-674-2465421, 2465446.
- Dr. M.G.R Fisheries College and Research Institute
Ponneri – 601 204 Thiruvallur District,
Tamil Nadu, India.
Phone: 044 – 2797 1556, 044 – 2797 1557.