Is 100% replacement of Artemia possible?
By Craig Browdy, Peter Van Wyk, Chris Stock, Diego Flores and Ramir Lee
Part 1: Artemia supply is a potential bottleneck to aquaculture’s growth
Achieving increasing global aquaculture production goals will strain Artemia supplies if the industry does not break its dependence on this natural resource. No commercially farmed species evolved with a requirement for Artemia and therefore it is not Artemia but its nutritional components that have proven so valuable to aquaculture.
Artemia is a primary feed for larval stages of various shrimp and fish species commercially-farmed throughout the world. The increasing demand globally for Artemia could make its supply and availability a bottleneck for the future growth of aquaculture. As supply is based on harvests of wild populations, it is unpredictable and subject to considerable variation due to factors such as changing environmental conditions. For example, various natural phenomena influence the harvests from the Great Salt Lake or GSL (Utah, USA), which provide between one-third to half of the global Artemia supply. Fluctuations in water level and salinity in the lake have been related to some of the most dramatic production irregularities.
Higher salinities can stress Artemia and limit reproduction while lower salinities make harvests more difficult because of reduced buoyancy of the cysts. These changes in the local environment can affect the natural food chain which Artemia depend on. Changes in the algae populations (with incidences of harmful algal blooms) and falling water levels in the GSL can considerably limit total Artemia populations, resulting in a significantly reduced global supply of cysts. The aquaculture industry continues to be exposed to significant fluctuations of Artemia cyst supply and pricing.
Various authors have projected an additional global seafood demand in the next two decades at up to double our current annual production of around 80 million tonnes. A recent World Bank report (Kobayashi et al., 2015) projected that global seafood supply will increase from 154 million tonnes in 2011 to 186 million tonnes in 2030. Almost all of the increase will come from aquaculture development. The fastest growth in aquaculture is expected for tilapia and shrimp (over 90% increase), while the largest expansion is expected in India, Latin America, the Caribbean and Southeast Asia, which are currently all major shrimp farming areas. Artemia, or rather, the nutrition currently provided by Artemia to larval shrimp, is critical in the production of shrimp seed stock.
Global Artemia production during the last 15 years has fluctuated. There are three main Artemia-producing regions in the world; GSL, various countries in the Commonwealth of Independent States (CIS or the Russian Commonwealth) and China. According to Litvinenko et al. (2015), total global production of Artemia in recent years is between ~3,000 and 4000 tonnes annually. This production comes from GSL with 1,000-2,000 tonnes; Russia, 550 tonnes; Kazakhstan, 20 tonnes; Uzbekistan, 20 tonnes; China (Bohai Bay, Mongolia, Aibi, Balikun and other areas), 900 tonnes; Vietnam, 20 tonnes; and other countries (Thailand, Argentina, Brazil and other salt ponds and lakes in the world) contributed ~ 60 tonnes. Thus, the three largest centres of Artemia cyst production are in the GSL, combined West Siberia and Kazakhstan and China.
More natural production is possible from a few areas such as the Crimea. But extractive and selective exploitation of a natural resource like Artemia cysts may not be a long-term, viable course of action to support the projected growth of aquaculture. There is evidence that harvesting of these populations may have negative effects. One example is the recent research by Sura and Belovsky (2016) who carried out a study of brine shrimp (Artemia franciscana) cysts in GSL to determine if selective harvesting can cause evolutionary responses in populations through changes in phenotypic characteristics, especially those affecting life history. Studying cysts harvested from 1991-2011, the authors reported that cyst buoyancy decreased and nauplii mortality increased over time. The authors concluded that harvesting A. franciscana cysts in the GSL is causing evolutionary changes with implications for the future sustainable harvest and management of the resource. These findings are from the GSL which many believe to be the best managed Artemia source in the world. Other global sources are not known to have such carefully regulated harvest systems in place and there are concerns on the impacts of poaching and illegal harvesting in some places. These factors only further undermine the predictability and sustainability of global Artemia supplies.
The Artemia supply situation today is very similar to that of the fish meal and fish oil supply some years ago. Growth of aquaculture was correlated with the increasing use of fish meal and fish oil, mainly derived from reduction fisheries. As both fish meal and fish oil reached maximum sustainable levels many years ago, there are increased efforts to expand the use of terrestrial and plant meals and oils as alternatives. The commercial aqua feed industry has been shifting and evolving; from using marine sources, mostly from capture fisheries which are subject to quotas, seasons and other limitations, to using land-based sources, farmed and industrial by-products (produced under controlled, scalable, sustainable and certifiable conditions). The same shift and evolution are possible for Artemia. The demand for Artemia for such a fast-growing aquaculture industry will overtake its production, and alternatives should be explored. Is Artemia production on land possible? Maybe, and there have been numerous attempts, often associated with the production of various microalgae species such as Dunaliellasalina. However, to date large scale cultures have not been successful and an alternative to Artemia is critical.
Developing a replacement diet
It is relevant to develop a single replacement diet for Artemia in shrimp hatcheries as well as understand how Artemia is used in different parts of the world. In the Eastern Hemisphere, hatched Artemia are traditionally fed based on visual macroscopic observations of available feed in the water. Microscopic observations are not commonly used. Also, larval production tanks normally have flat bottoms and low aeration levels, which make the suspension of artificial feeds difficult. Therefore, there is a very high dependence on live Artemia, which are easily seen with the naked eye and maintained in suspension.
In the Western Hemisphere, the use of artificial diets is considerably higher. Feeding is based more on frequent microscopic observation of the animals than on observations of the water column. Larval production tanks with parabolic bottoms are used, with high levels of aeration in the centre to maintain all feeds in suspension and minimize dependence on live feeds.
Most Artemia cysts are used to produce Pacific white shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeusmonodon), each with different feeding characteristics. P. monodon, up to the post larvae (PL20) stage, are mainly pelagic feeders feeding near the top of the water column. They are mainly cultured in flat bottom tanks and are not efficient at feeding off the bottom, making it difficult to feed dry diets up to the time of harvest. They can only feed on what stays in the water column in a flat bottom tank (i.e. live Artemia). It is typical to use 5-10 kg of Artemia 80% hatch-out cysts/million P. monodon post larvae produced.
Litopenaeus vannamei are pelagic feeders up to the PL5 stage, and then become benthic feeders from PL6 to the time of harvest, which permits significant use of inert diets in the later stages and lowering of the amount of Artemia needed. They are mainly cultured in tanks with parabolic bottoms until PL5. After PL5, Artemia hatched from cysts are no longer used as feeds and the animals are fed at the bottom with heavier, sinking diets as well as de-capsulated cysts or Artemia biomass. It is typical to use 1- 5 kg of Artemia 80% hatch-out cysts/million L. vannamei post larvae produced.
A replacement for Artemia
Earlier we stated that there is a better alternative to sustainably meet the nutritional requirements for the production of shrimp post larvae. Recognizing the limitations and biosecurity risks of live feeds, our company developed a commercial, cost-effective replacement diet for the Artemia.
Artemia has many benefits but it also has some significant disadvantages. The high variability in cost, availability, nutritional value, and hatch rates are growing concerns. In addition, Artemia can be a potential disease vector, particularly for Vibrio contamination, thus raising biosecurity concerns. For example, the microsporidian parasite that causes the EHP disease, Enterocytozoon hepatopenaei, has been identified in Artemia biomass. Hatching and rearing of Artemia require considerable resources in terms of infrastructure, labour and time which are often not accounted for in the cost of using cysts.
In contrast, a complete and artificial Artemia replacement has several benefits. Artificial feeds can be produced with a consistent nutritional profile that can equal or exceed that of Artemia nauplii. Artificial feeds can also be certified as pathogen-free alleviating biosecurity concerns. Prepared diets have consistent availability and quality. There are no inconsistencies related to hatching percentages or presence of shells and unhatched cysts, and no infrastructure or variable costs to the hatchery. The feeds can be used for delivery of immunostimulants, enzymes and other beneficial compounds, as well as probiotics to enhance digestion and improve water quality and animal health. Overall, using an artificial, biosecure product that delivers the nutritional needs and can be produced on demand, enhances planning, operations and predictability while reducing risks.
100% replacement diet for the Artemia is the result ofalmost 20 years of experience and continuous improvement. It isa liquid diet and with near neutral buoyancy and was formulatedto match the nutrient profile of high quality enriched Artemiawith high levels of highly unsaturated fatty acids (HUFA). It isdesigned to completely replace Artemia cysts by up to 100%,depending on various factors. Nutritional composition is optimalfor shrimp post larvae; on dry weight basis, 52% protein and17% lipid and on wet weight basis, 14 % protein and 4.5% lipid.The diet has two practical presentation sizes: 50-200 micronsfor feeding zoea, mysis and post larvae stages (Z1 – PL2) and300-500 microns for PL2 – PL12. This replacement diet providesconsistent nutrition and has no disinfection or hatching costs. Itscost is significantly less than Artemia cysts. In addition, it hasbeen shown to extend the transport time of shrimp post larvaeby helping maintain good water quality and dissolved oxygen levels.
Liquid diets for shrimp larvae have several advantages when compared to other products such as dry diets, because they are microencapsulated; the cold manufacturing process protects sensitive ingredients (enzymes, fatty acids, pigments, etc.) from heat degradation. They have a semi-moist texture, are highly attractive, palatable, and water stable as well as significantly better in reducing leaching and water pollution in the rearing units.
Next issue: Part two of this article will cover results of field trials at the hatchery and pond stages in commercial facilities as well as some perspectives for this important resource.
Kobayashi, M., Msangi, S., Batka,M., Vannuccini, S., Dey, M.M. and Anderson, J.L. 2015. Fish to 2030: The Role and Opportunity for Aquaculture. Aquaculture Economics & Management Vol. 19, Issue 3, 2015.
Litvinenko, L.I., Litvinenko, A.I., Boiko, E.G. and Kutsanov, K. 2015. Artemia cyst production in Russia. Chin. J. Oceanol. Limnol., 33(6): 1436-1450.
Sura, S.A and Belovsky, G.E. 2016. Impacts of harvesting on brine shrimp (Artemia franciscana) in GSL. Ecol Appl. 2016 Mar;26(2):407-14.
Craig Browdy is Director of Research & Development
Peter Van Wyk is R&D Technical Manager
Chris Stock is Sales Manager - Eastern Hemisphere.
Diego Flores is Technical Representative – Hatchery Feeds – Western Hemisphere and
Ramir Lee is Technical Representative – Hatchery Feeds – Eastern Hemisphere.
All authors are with Zeigler Bros., Inc. USA.
AQUA Culture Asia Pacific Magazine - March/April 2017