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Rotifers as Artemia Replacements
This discussion on the use of rotifers in shrimp hatcheries took place on the Shrimp List. Contact information on the participants appears at the end of the article.
D. Ramraj, director of Padmanabha Labs, which does PCR testing in India, got the discussion going with the following comment: Please share your experience in using rotifers as an Artemia replacement in shrimp hatcheries.
Dr. Dallas Weaver, who owns Scientific Hatcheries, a supplier of live feeds to the aquarium trade, responded:
China has used a lot of rotifers in shrimp larval culture and may be your best source of information on the topic.
I have used rotifers with Penaeus vannamei and they love them. Even near-adult shrimp will rise up in the water column and use their legs to filter-feed the rotifers from the water. PLs also do very well on rotifers, but I was still using Artemia at the time of these experiments because my rotifer supply was not reliable. Although I am no longer working with P. vannamei, I have now substituted rotifers for Artemia in larval fish culture. I’m using a new, continuous culture system that appears to be reliable and stable. It is still in the development phase, but I am averaging about 8 kilos of wet weight rotifers per day.
Rotifer production has very significant economies of scale. Labor cost is almost independent of production levels. I am using yeast and other nutrients in a continuous production system with L-type rotifers. It looks like large rotifer production systems will beat the cost of producing live Artemia nauplii.
David Griffith, general manager of Sea Farms International’s operations in Venezuela, added:
CENAIM, a shrimp research group in Ecuador, has done a considerable amount of work with rotifers and shrimp larval rearing; it would probably be a good source of information.
Phil Boeing, a shrimp farming consultant:
In the early 1980s, the Kuwait Institute of Scientific Research (KSIR) did some interesting studies on the consumption of rotifers by P. semisulcatus. In other studies, Browdy and Samocha indicated that the growth of penaeid shrimp larvae on a rotifer diet was inferior to that of Artemia. In South Africa, Emerson indicated that the energetics of a rotifer diet versus Artemia were low—but these studies were done before enrichment diets hit the market.
Several studies that we did with the Algamac-2000 enrichment diet [Aquafauna Bio-Marine, address below] showed a superior uptake of DHA by rotifers compared to Artemia. It appears Artemia retroconvert DHA to EPA once it reaches a certain level in their system.
The success of extensive penaeid larvae rearing systems using rotifers in areas where Artemia and enrichment diets are prohibitively expensive or unavailable indicates that they are an alternative worth considering.
As Dallas pointed out, it will all come down to whether you can produce the quantity of rotifers you need more cost effectively than the price of Artemia.
Hank Bauman, farm manager at Belize Aquaculture, Ltd.:
I cultured Brachionus (sp?) for milkfish in the Philippines and tried feeding them to mysis stage P. monodon. I watched them in the beaker and looked at gut content under the microscope. I saw no evidence that they were eating any at all.
Dr. M. Rufus Kitto, senior biologist with Gulf International Aquaculture Company, a consulting company in Kuwait:
With monodon, the best option would be to adjust the enrichment process to match the nutritional requirements of the developing larvae.
Use naturally DHA-fortified Isochrysis cell autolysates enriched rotifers for mysis stage shrimp, crab egg enriched rotifers for early postlarvae, and minced clam liquor enriched rotifers for late postlarvae.
A sodium nifurstyrenate-bath rinsing is a must before feeding.
This regime is never a total supplementation for Artemia, but 50% substitution is possible.
The crucial factor is the cheap production of rotifers outdoors with outdoor grown algae (Chlorella) fertilized with commercial fertilizers and sterilized clam paste or sterilized poultry intestine paste to reduce production cost. Yeast is an additional feed in the culture process.
Leland Lai, a director of Aquafauna Bio-Marine, a supplier of shrimp hatchery feeds:
Many marine fish hatcheries incorporate rotifers in their larval diets because rotifers are smaller than Artemia. With shrimp, Artemia is usually introduced in the mysis stage, but most species can survive on rotifers from earlier stages.
In marine culture, as Dr. Kitto and others suggest, rotifers are not a perfect diet and the research definitely indicates enrichment makes the difference in their nutritional value, especially for marine organisms.
There are, as indicated by Dallas, nonliving substitutes that can replace the live algae commonly used for rotifer culture. Some of these are commercially available. Reed Mariculture, Aquafauna Bio-Marine, Pacific Trading (Japan), to name a few, have such alternatives. Cost is the issue and some are available for under US$30.00 a kilo on a dry weight basis. Compare this to the cost of culturing live algae at between $60 to more than $100 a kilo on a dry weight basis.
There are also a wide number of choices for enriching rotifers, like Super Selco, fish emulsions and heterotrophic algae like Schizochytrium (AlgaMac) and Crypthecodinium (AquaGrow). In the end, users will gravitate to the simplest and least cost products, especially those that are easy to ship and store.
Eric Pinon, who runs Service Aqua, LLC, an aquaculture consulting company:
I would not recommend poultry by-product use in shrimp farming. Chickens are commonly fed “growth promoters”, which are antibiotics at low doses, and other magic bullets to control their health. You could compromise the food safety of your shrimp by using poultry by-products.
Dr. Dallas Weaver (above):
The correct solution to rotifer biomass production will be site specific. I have high value land, high labor costs and excellent infrastructure, so I go high-tech with automated, instrumented systems. Chinese methods are at the other end of the spectrum.
Shrimp News added the following background information to the discussion:
1. In this study, a feasibility study was performed on a recirculating system for mass culturing rotifers. With a culture volume of 750 liters, the system was tested at stocking densities of 3,000, 5,000 and 7,000 rotifers per milliliter. At all densities, it produced 2.2 billion rotifers a day for three weeks. Protein skimmers, ozone and a submerged biofilter maintained excellent water quality. Microbial counts were stable. For the first year, compared to a commercial batch culture system, capital costs were reduced by 46%; labor costs, by 65%; and feed costs, by 21%. Source: Electronical Larviculture Newsletter. Technical and economical feasibility of a rotifer recirculation system. G. Suantika
(firstname.lastname@example.org), P. Dhert, E. Sweetman, E. O’Brien and P. Sorgeloos (Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Rozier 44, B-9000, Gent, Belgium). Issue 185, November 1, 2003.
2. Reed Mariculture offers free plans for a high-density rotifer culture system called the Instant Algae Rotifer System that can be assembled from parts you can get from a local supplier. The system replaces low-density batch production in large growout tanks with continuous production in small, high-density tanks. It’s a low-maintenance design that only requires a few minutes of maintenance a day. The documentation and diagram for the system are available at http://www.rotifer.com.
• Produces more than 500 million rotifers every day from a 500-liter tank
• Uses less than 10% of the space required for batch systems
• Requires less than 15 minutes of maintenance a day
• Is easy to understand, build and operate
• Is scalable from 50 to 5,000 liters
• Is inexpensive (feed costs 8 to 11 cents per million rotifers)
• Costs less than $1,000 to build
Information: Randy Reed, Reed Mariculture, Inc., 511 Palmiar Avenue, Suite C, Santa Jose, CA 95128 USA (phone 408-288-8121, fax 408-884-2322, email email@example.com, webpage http://www.instant-algae.com). Source: Dave Conley’s Aquaculture Newsclips (no longer published, firstname.lastname@example.org). New rotifer bioreactor system. Item #9. November 10, 2002.
3. Rotifer and Microalgae Culture Systems (1991) is a 364-page (216 x 280 mm) manual, edited by Wendy Fulks and Kevan Main, at the time employees of The Oceanic Institute in Hawaii. It is the proceedings of a United States/Asia workshop held in January 1991. The workshop focused on the techniques and hardware used to culture rotifers and microalgae in Asia and the United States. The indexed proceedings summarizes the findings of the workshop. The introduction furnishes background information on the design of microalgae and rotifer culture systems, emphasizing ways to improve reliability and reduce operating costs. The next section contains 22 papers describing production techniques in the United States, Japan, the People’s Republic of China, the Republic of Korea, Thailand, Singapore and Taiwan. The final section outlines the information exchanged in the discussion groups. Appendices contain the names and addresses of workshop participants. It sells for $85.00 (reference #B-ROTI-MCS). Information: Thomas Sawtell, Argent Chemical Laboratories, Inc., Argent Laboratories Press, 8702 152nd Avenue, N.E., Redmond, WA 98052 USA (phone 425-885-3777, fax 425-885-2112, webpage www.argent-labs.com).
D. Ramraj, Padmanabha Labs, Pvt., Ltd., 7-15-15 Priyadarshini Building, Lawyerpet, Ongole 523 002, AP, India (phone 91-8592-224205, fax 91 8592 227365, email email@example.com).
Dallas E. Weaver, Scientific Hatcheries, 5542 Engineer Drive, Huntington Beach, CA 92649 USA (phone 714-890-0138, fax 714-890-3778, email firstname.lastname@example.org, webpage http://www.scientifichatcheries.com).
David Griffith, Seafarms International, 11430 S.W. 88th Street, Suite 309, Miami, FL 33176 USA (email email@example.com, webpage www.seafarmsinternational.com).
Phil Boeing, 53300 Avenida Navarro, La Quinta, CA 92253 USA (phone 760-564-1421, email firstname.lastname@example.org).
Hank Bauman, Belize Aquaculture, Ltd., #1 King Street, Box 37, Belize City, Belize (phone 501-2-7703, fax 501-2-77062, email email@example.com).
Dr. M. Rufus Kitto, Gulf International Aquaculture Company, P.O. Box 36420, Raas 24755, Kuwait (phone 00965, fax 5718490, email firstname.lastname@example.org).
Leland Lai, Aquafauna Bio-Marine, Inc., P.O. Box 5, Hawthorne, CA 90250 USA (phone 310-973-5275, fax 310-676-9387, email email@example.com, webpage www.aquafauna.com).
Eric Pinon, Service Aqua, LLC, 5600 North US#1, Ft. Pierce, FL 34946 USA (phone 772-465-1577, fax 772-264-8076, email firstname.lastname@example.org, webpage http://serviceaqua.com/webserviaqua1.htm).
Source: The Shrimp List (page 276). Subject: [shrimp] Rotifers in shrimp larval rearing. August 6, 2004.
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