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May | June 2013EXPERT TOPIC - SHRIMPThe International magazine for the aquaculture feed industryInternational Aquafeed is ...
42 | InternatIonal AquAFeed | May-June 2013EXPERT	T●PICWelcome to Expert Topic. Each issue will take an in-depth lookat a ...
ShrimpFarmed	shrimp	was	a	$US10.6	billion	indus-try	 in	 2005	 (WWF).	The	 species	 is	 one	 of	the	 fastest	 growing	 in	...
2IndiaIn	the	1990s,	Indian	shrimp	aquaculture	expe-rienced	 rapid	 growth.	 Production	 increased	from	 30,000	 tonnes	 in...
Innovations for a better world.Bühler AG, Feed & Biomass, CH-9240 Uzwil, Switzerland, T +41 71 955 11 11, F +41 71 955 28 ...
Causeof EMSdetectedThe	 pathogen	 which	causes	early	mortality	syndrome	 (EMS)	 has	been	 identified	 by	researchers	 at	 ...
Providing proficient tools to achieve cost-effective and sustainable aquaculture practicesCentral Office and OrdersJesús A...
Applicationof isotopictechniquesto assess thenutritionalperformance ofmacroalgae infeeding regimesfor shrimpby Julián Gamb...
trophic	level	(primary	producers,	herbivores,	carnivores).	In	the	case	of	plants	and	macroalgae,	their	carbon	isotope	valu...
weight	of	shrimps	under	the	different	dietary	treatments;	 however,	 a	 clear	 tendency	 for	higher	growth	was	observed	in...
tion	of	structural	carbon	and	nitrogen	when	co-fed	with	formulated	feed.	However,	 the	 high	 amount	 of	 nutrients	derive...
AQUAFEED6 ISSUESInternational	Aquafeed	is	published	six	times	a	year,	bringing	you	in-depth	features,	industry	news,	event...•	 See the full issue•	 Visit the International Aquafeed website•	 Contact the International Aquafe...
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Due to their nutritional properties, several species of macroalgae have been used as dietary supplements for shrimps and other marine species. Since macroalgae represent a natural source of nutrients in the shrimp’s natural environment, attempts have been done to co-culture macroalgae and shrimps.

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  1. 1. May | June 2013EXPERT TOPIC - SHRIMPThe International magazine for the aquaculture feed industryInternational Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies,the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis ofinformation published.©Copyright 2013 Perendale Publishers Ltd.All rights reserved.No part of this publication may be reproduced in any formor by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058INCORPORATINGf ish farming technolog y
  2. 2. 42 | InternatIonal AquAFeed | May-June 2013EXPERT T●PICWelcome to Expert Topic. Each issue will take an in-depth lookat a particular species and how its feed is managed.SHRIMPEXPERT TOPIC
  3. 3. ShrimpFarmed shrimp was a $US10.6 billion indus-try in 2005 (WWF). The species is one of the fastest growing in aquaculture with an approximate rate of 10 percent annually. The production of whiteleg shrimp (Litopenaeus vannamei, formerly Penaeus vannamei) in particular, generated the highest value of major cultured species at $US11.3 billion.L. vannamei was first cultivated in Florida in 1973 from larvae spawned and shipped from a wild-caught mated female from Panama. In 1976, due to good pond results and adequate nutrition, the culture of L. vannamei began in South and Central America. By the early 1980s, through intensive breeding and rearing techniques, L. vannamei was being developed in the USA (including Hawaii), and much of Central and South America (FAO). L. vannamei is popular because of its high yield and short grow out period. The yield per hectare is up to three times that of the giant tiger shrimp (Penaeus monodon). The grow out period is also shorter for L. van-namei, 60-90 days, compared to 90-120 days for P. monodon. Overall, it costs about half as much to produce a kilo of L. vannamei as it does to produce a kilo of P. monodon.1ChinaAlthough, L. vannamei was introduced into Asia in 1978-9, it was not until 1996 that the species was cultivated on a commercial scale. First in Mainland China and Taiwan and subse-quently to the Philippines, Indonesia, Vietnam, Thailand, Malaysia and India. The largest seafood producer and export-er in the world, China also boasts a large L.vannamei production industry, with Mainland China producing more than 270,000 met-ric tonnes in 2002. Production reached an estimated 300,000 metric tonnes (71% of the country’s total shrimp production) in 2003 and hit 700,000 tonnes in 2004 (Network of Aquaculture Centres in Asia-Pacific). More InforMatIon:www.enaca.orgbyMarnieSnellMay-June 2013 | InternatIonal AquAFeed | 43EXPERT T●PIC314526
  4. 4. 2IndiaIn the 1990s, Indian shrimp aquaculture expe-rienced rapid growth. Production increased from 30,000 tonnes in 1990 to 102,000 tonnes in 1999 (FAO). This expansion brought economic success for the country. By the start of the 21st century, the shrimp aquaculture sector accounted 1.6 percent of Indian export earnings and employed an estimated 200,000 people.Yet the development of shrimp aquac-ulture has become more controversial. The introduction of L. vannamei in 2009 has led to widespread illegal farming and posed the threat of disease. However, there are organi-sations dedicated to tackling the problem. One example is the Coastal Aquaculture Authority (CAA) which aims to shut down unregistered shrimp hatcheries and farms. The scale of the issue is rather large as out of 14,549 CAA registered farms, just 246 have permission to cultivate whiteleg shrimp. More 1970s set a president for the devel-opment of Ecuador’s shrimp farming industry. L. vannamei, captured from the beach surf was transferred into 20-hec-tare ponds that Ecuadorian producers built on mud flats. During the mid-1970s, animal feed and pet food company, Ralston Purina began conducting pond trials in Ecuador to demonstrate the benefits of feeding. As land and labour were cheap, disease was rare and wild seed was in abundance, the shrimp farming business was profitable and by 1977, approxi-mately 3,000 hectares of extensive shrimp farms had been developed in Ecuador.As a result, shrimp feed mills were developed during the 1980s, marking the transition of Ecuadorian farms from extensive to semi-intensive production.More shrimp farming was already operational during the 1980s, it was the introduction of L. vannamei in 1992 that allowed for a swift expansion in Brazil’s shrimp farming industry. Shrimp culture is now one of the most organised sectors within Brazilian aquaculture.In 2003, the total production of L. van-namei reached 90,190 tonnes produced from 14,824 ha of shrimp ponds. In some states, productivity reached 8,700 kg/ha/year with the best yields obtained in the northeast region.With exports reaching 60,000 tonnes in 2003, representing 60.5% of the total Brazilian fishery export and generating US $230 million for the Brazilian economy, shrimp culture is now one of the most important economic activities in the Northeast region.Most of the shrimp farms are small scale (75 %), followed by medium (9.6%) and large scale (5.52%). The average yield increased from 1 015 kg/ha/year in 1997 to 6,084 kg/ha/year in 2003, compared to an international average of 958 kg/ha/year (FAO).More farming has been practised in Thailand for more than 30 years, with its development expanding rapidly during the mid-1980s. This expansion was supported by advances in shrimp feed and the successful production of larvae in 1986.The most popular shrimp cultivated in the country is the giant tiger prawn (Penaeusmonodon) which accounts for 98 percent of shrimp production and around 40 percent of total brackish water aquaculture production (FAO). L. vannamei was first introduced to Thailand in the late 1990s as an alternative to the native P. monodon. The production of L. vannamei in Thailand rapidly increased from 10,000 metric tons in 2002 (Briggs et al. 2004) to approximately 300,000 metric tons in 2004, which com-prised 80 percent of total marine shrimp production.More’s indigenous shrimpThe Rajiv Gandhi Centre for Aquaculture (RGCA) in Tamil Nadu, India has produced a specific pathogen free variety of shrimp. The new variety is set to help commercial shrimp farmers and boost India’s seafood exports.The selectively bred mother shrimps are capable of producing quality seeds that harness higher growth and survival rates.Until now, Indian shrimp hatcheries imported such brood stock from the USA, Thailand and Singapore, resulting in high shipping costs and big transit losses. The average cost of brood stock was estimated at Rs5,000. It is estimated that 80 percent of India’s shrimp farmers are small scale - the quality of seeds largely affects their crop success. Due to the high costs, some hatcheries have been sourcing brood stock from shrimp ponds, which ultimately results in the production of poor quality seeds and subsequent crop loss to farmers. 244 | InternatIonal AquAFeed | May-June 2013EXPERT T●PIC
  5. 5. Innovations for a better world.Bühler AG, Feed & Biomass, CH-9240 Uzwil, Switzerland, T +41 71 955 11 11, F +41 71 955 28, www.buhlergroup.comFatten up your bottom line. Bühler high-performance animal and aqua feed productionsystems are used by leading companies around the world. These producers know theycan rely not just on the technology itself, but also on the support that accompanies it. Aservice combining local presence with global expertise both lowers feed mill operatingcosts and increases capacity utilization. To find out more, visit
  6. 6. Causeof EMSdetectedThe pathogen which causes early mortality syndrome (EMS) has been identified by researchers at the University of Arizona, USA.A research team led by Donald Lighter found that EMS, or more technically known as acute hepatopancreatic necrosis syndrome (AHPNS), is caused by a bacterial agent, which is transmitted orally, colonizes the shrimp gastrointestinal tract and produces a toxin that causes tis-sue destruction and dysfunction of the shrimp digestive organ known as the hepatopancreas.The disease was first record-ed in China in 2009 and has since spread to Vietnam (2011), Thailand (2012) and Malaysia (2012). EMS kills shrimp between 10-40 days after the post-larval stage with mortalities of up to 70 percent. Shrimp that survive suffer from stunted growth and tale twice as long to achieve significant grow out. The economic impact of EMS is perhaps yet to be fully felt. However, the dis-ease is one of the most sig-nificant reasons in the fall in Thai shrimp production. In 2010, the country produced 600,000 toms of shrimp but by 2012, this figure has fallen to 500,000 tons, a drop of around 18 percent.Lightner’s team identified the EMS pathogen as a unique strain of a relatively common bac-terium, Vibrio parahaemolyticus, that is infected by a virus known as a phage, which causes it to release a potent toxin. A simi-lar phenomenon occurs in the human disease cholera, where a phage makes the Vibrio cholerae bacterium capable of producing a toxin that causes cholera’s life-threatening diarrhea. EMS how-ever, is not a danger to people.Research continues on the development of diagnostic tests for rapid detection of the EMS pathogen that will ena-ble improved management of hatcheries and ponds, and help lead to a long-term solution for the disease. It will also enable a better evaluation of risks associ-ated with importation of frozen shrimp or other products from countries affected by EMS.Some countries have imple-mented policies that restrict the importation of frozen shrimp or other products from EMS-affected countries. Lightner said frozen shrimp likely pose a low risk for contamination of wild shrimp or the envi-ronment because EMS-infected shrimp are typically very small and do not enter international commerce. Also, his repeated attempts to transmit the disease using frozen tissue were unsuc-cessful.In an effort to learn from past epidemics and improve future policy, the World Bank and the Responsible Aquaculture Foundation, a charitable edu-cation and training organisa-tion founded by the Global Aquaculture Alliance, initiated a case study on EMS in Vietnam in July 2012. Its purpose was to investigate the introduction, transmission and impacts of EMS, and recommend manage-ment measures for the public and private sectors.646 | InternatIonal AquAFeed | May-June 2013EXPERT T●PIC
  7. 7. Providing proficient tools to achieve cost-effective and sustainable aquaculture practicesCentral Office and OrdersJesús Aprendiz, 19. 1º A-B28007 MadridT. +34 915 014 www.norel.esAqua RangeFUNGINAT AQUAECOBIOL AQUAAQUABONDGLYMET MIX AQUA AQUANOXGUSTOR AQUAQUABONDGUSTOR AQUAAQUANOX
  8. 8. Applicationof isotopictechniquesto assess thenutritionalperformance ofmacroalgae infeeding regimesfor shrimpby Julián Gamboa-DelgadoPhD, research officer, ProgramaMaricultura, Universidad Autónomade Nuevo León, MexicoDue to their nutritional prop-erties, several species of macroalgae have been used as dietary supplements for shrimps and other marine species. Since macroalgae represent a natural source of nutrients in the shrimp’s natural environment, attempts have been done to co-culture macroalgae and shrimps. The nutritional performance and digestibil-ity of macroalgae-derived meals have been tested in formulated diets for shrimp. One of the aspects requir-ing further research is represented by the loss of nutritional properties occurring when the macroalgal biomass is dried out as compared when the algal biomass is ingested as live biomass. Several nutritional method-ologies have been used to evalu-ate the performance of different ingredients used or proposed for aquaculture feeds. The use of stable isotopes as tools to assess nutritional contributions of specific ingredients to growth is one of many emerging nutritional techniques applied in aquaculture.The chemical composition of macroalgae varies among species and environmental con-ditions; however, most are rich in non-starch polysaccharides, vitamins, and minerals. In particular, green macroalgae (Chlorophyceae) often have higher protein content than brown seaweeds. Such nutritional properties, in con-junction with novel macroalgae production methods, have increased the interest in their use as dietary ingredients for aquaculture diets. Additionally, there are studies that have focused on their use as additives to enhance the immunological status of the farmed animals. The green macroalgae Ulva (Enteromorpha)clathrata, also known as aonori in Asian countries, has worldwide distribution and due to its nutritional profile, has been evaluated as a dietary supplement for aquatic species. U. clathrata has been mass-cultured in recent years under a patented technology developed by Aonori Aquafarms Inc. By applying this methodology, macroalgae biomass is rapidly grown in ponds without eliciting detrimental effects to the environment. Evaluation of macroalgae inshrimp nutrition studiesAlthough it has been observed that use of macroalgal biomass alone as feed does not fulfil the nutritional requirements for optimal growth in marine shrimp, co-culture of U.clathrata and Pacific white shrimp L. vannamei has been conducted with positive results in terms of lower feed utilization and improve-ment of the shrimp nutritional quality, flesh colour and texture. Recent nutritional studies have also shown that when dry Ulva clathrata meal is fed to Pacific white shrimp as an ingredient in practical diets, it has an apparent digestibility coefficient for dry matter of 83 percent, while the same value for protein is 90 percent. However, the high ash content and the rela-tively low protein content of this macroalgae species prevent its dietary inclusion at high levels when attempting to replace other ingredients such as fishmeal. Stable isotopes to assessthe nutritional contributionof macroalgaeOver the last few decades, different iso-topic methodologies have been adopted from the ecological sciences and have been applied to animal nutrition studies. Most elements in organic matter are present as two or more stable isotopes and heavier isotopes have a tendency to accumulate in animal tissue. For example, animal predators have higher isotopic values than their preys; therefore, a specific isotopic signature is conferred to each Table 1: Growth, survival rate and estimated consumption of formulated feed and livemacroalgae biomass (dry weight) by juvenile litopenaeus vannamei reared on five differentfeeding regimes for 28 days (n= 8-20, mean values ±SD)FeedingregimeSurvival (%)Final wetweight (mg)Weightincrease (%)Consumedformulatedfeed (g)ConsumedU. clathrata(g)100F 95 ± 13a 995 ± 289a 429 0.94 -75F/25U 93 ± 11a 1067 ± 364a 467 0.81 0.4050F/50U 78 ± 11ab 768 ± 273ab 308 0.43 0.4425F/75U 60 ± 21b 424 ± 207b 125 0.14 0.65100U* 23 ± 4c 221 ± 49c 18 - 1.32Initial wet weight = 188 ±28 mgDifferent superscripts indicate significant differences at p<0.05* Parameters in animals from feeding regime 100U were estimated on experimental day 21Juvenile Pacific white shrimpfeeding on U. clathratamacroalgal biomass. Long fecalstrands are frequently relatedto fast gut transitImagecourtseyofAlbertoPena©748 | InternatIonal AquAFeed | May-June 2013EXPERT T●PIC
  9. 9. trophic level (primary producers, herbivores, carnivores). In the case of plants and macroalgae, their carbon isotope values are strongly influenced by the type of photosynthesis they present. On the other hand, the nitrogen stable iso-tope values of plants and macroalgae can be easily manipulated by means of specific fertilis-ers, to eventually conduct nutritional studies. By using such techniques, it can be possible to determine the proportions of available dietary nutrients that have been selected, ingested and incorporated into animal tis-sue (Figure 1). As the average sample size required for stable isotope analysis (carbon and nitrogen) is only 1 mg of dry tissue or test diet, the technique has been very useful in larval nutrition studies. It has been employed to quantify the proportions of nutrients incor-porated from live and formulated feeds in fish and crustacean larvae. Likewise, stable isotope analyses of dif-ferent plant-derived ingredients (soy protein isolate, corn gluten and pea meal) have been carried out to explore the contribution of the dietary nitrogen supplied by these sources (as compared to fish meal) to shrimp growth. In the context of macroalgae as source of nutri-ents, isotopic techniques have been applied as nutritional tools to quantify the relative contributions of dietary carbon and nitrogen to the growth of Pacific white shrimp co-fed formulated feed and live macroalgal biomass of U. clathrata. ExperimentaldesignTaking advantage of the contrast-ing natural carbon and nitrogen stable isotope values meas-ured in a commercial formulated feed and in live macroalgal bio-mass of U. clathrata, the study aimed to quantify the relative contribution of nutri-ents to the growth of Pacific white shrimp. Animals were allocat-ed to duplicate tanks individually fitted with air lifts and connected to an artificial-seawater recirculation system. Feeding regimes consisted of a positive isotopic control (100% formulated feed, treatment 100F), a negative isotopic control (100% macroalgae, treatment 100U) and three co-feeding regimes in which 75, 50, and 25 percent of the daily amount of con-sumed macroalgal biomass was substituted by formulated feed (treatments 75F/25U, 50F/50U, and 25F/75U, respectively) on a dry weight basis. The digestibility of both feeding sourc-es for L. vannamei has been previously assessed and is similarly high (>80%). Live macroalgae was supplied to shrimp by attaching the algal biomass to plastic mesh units from which the algal filaments were constantly available and easily nibbled upon by shrimp. Feeding rations and proportions were pro-gressively adjusted in relation to the amount of macroalgal biomass consumed, animal sur-vival and sampling. Shrimp samples (whole bodies and muscle tissue) and diet samples were collected and pre-treated for isotopic analysis.Growth and survivalThere was a high variability in final wet Figure 1: Carbon and nitrogen flow in shrimps producedunder semi-intensive farming conditions. Bold arrowsindicate components that can be isotopically analyzed todetermine their origin and fateMay-June 2013 | InternatIonal AquAFeed | 49EXPERT T●PICUsing unique macroalgae formulas toimprove health, taste and quality of shrimp100% Marine Natural DietA New Dimensionin Sustainable AquacultureFeed Ingredients from the SeaT: +353 (0)93 51807E: info@oceanharvest.ieScientifically provenactivity againstwhITe SpoT vIrAl dISeASe& lower FCrNeed to keep up to date with news about shrimp?Global Aquaculture News scours the web every day to bring you all of the latest information available. Visit:
  10. 10. weight of shrimps under the different dietary treatments; however, a clear tendency for higher growth was observed in shrimps reared on regime 75F/25U (1,067 ±364 mg, final mean weight), followed by shrimps fed only on formulated feed (995 ±289 mg). Shrimps from both feeding regimes increased their weight more than 400 percent (Table 1). Animals fed only on U. clathrata bio-mass showed very low growth (221 ±49 mg) and only 23 percent of the animals in this treatment survived by day 21. Higher survival rates (93-95%) were observed in shrimps reared on feeding regimes 100F and 75F/25U, while shrimps in dietary treatments 50F/50U and 25F/75U had respective mean survival rates of 78 and 60 percent. The positive effect of supplying both, live feeds and formulated diets has been recurrently observed in previ-ous crustacean studies.Dietary contributionsfrom macroalgae andformulated feedAt the end of the experi-ment, isotopic values of shrimp tissue reared on co-feeding treatments were strongly biased towards the isotopic values of U. clathrata biomass. Figure 2 combines carbon and nitrogen stable isotope values measured in shrimps and provides a graphic indica-tion of the total organic matter contributed by both, the for-mulated feed and macroalgae. Results from an isotopic mixing model indicated that shrimps in the three co-feeding regimes incorporated significantly higher amounts of dietary carbon and nitrogen from U. clathrata biomass than from the formulated feed (Table 2). At the end of the experiment, shrimps in treatment 75F/25U incorporated 68 percent of carbon from the formulated feed and 32 percent from the macroalgae. Shrimps under feeding regimes 50F/50U and 25F/75U incor-porated significantly higher amounts of dietary carbon from U. clathrata (49 and 80%, respec-tively) when compared to the expected dietary carbon proportions supplied by these the co-feeding regimes (34 and 70%, respec-tively). Shrimp grown in co-feeding regime 75F/25U incorporated 27 percent of nitrogen from the formulated feed and the remaining 73 percent from the macroalgal biomass, while animals reared on regimes 25F/75U and 50F/50U incorporated the majority of their dietary nitrogen (98 and 96%, respectively) from the macroalgae. The lower growth attained by these ani-mals indicated that a very high proportion of the isotopic change was due to high nitrogen metabolic turnover and not to tissue accre-tion. Due to its lower carbon and nitrogen contents, the macroalgal biomass had to be consumed at higher amounts in order to sup-ply the observed elemental contributions to shrimp whole bodies and muscle tissue. The availability andincorporation of nutrients fromformulated and live feedsThe higher than expected contributions of macroalgal carbon and nitrogen to shrimp growth are possibly related to the high digestibility of U. clathrata and its continuous availability for shrimp. Chemical analyses of U.clathrata have shown that it typically contains low to medium protein levels (20 - 30%) and very low lipid levels. The cell wall polysac-charides in macroalgae might represent more than half of dry algal matter, but a tentative role of the latter as energy source is unlikely as specific enzymatic activities for these polysac-charides (ulvanase, fucoidanase) have not been reported for Penaeid shrimps. Despite their lower nutrient concentration, live feed contains higher water content which contrib-utes to higher digestibility. In contrast, formulated feed can contribute nutrients that are scarce or absent in live feed, but the incorporation of such nutrients is limited by low feed digestibility or unsuitable formulation. Previous co-feeding experiments conducted on postlarval shrimp and larval fish have shown that the supplied live feed frequently contributes higher proportions of nutrients to the growth of the consuming animals than those supplied by formulated feeds in co-feeding regimes.ConclusionAlthough the live macroalgae by itself was not nutritionally complete for Pacific white shrimp, it supplied a very significant propor-Table 2: estimated contribution of dietary nitrogen suppliedfrom formulated feed and live biomass of Ulva clathrata andincorporated in tissue of postlarval Pacific white shrimp L.vannamei as indicated by stable isotope analysis.Feeding regimeexpected* observedWholebodiesMuscletissue75F/25UFormulated feed 79.6a** 15.9 b 20.5 bUlva biomass 20.4 84.1 79.550F/50UFormulated feed 66.1a 2.2 b 6.9 bUlva biomass 33.9 97.8 93.125F/75UFormulated feed 30.1a 1.0 b 3.2 bUlva biomass 69.9 99.0 96.8*Expected proportions are estimated from the actualproportions of formulated feed and macroalgal biomassoffered (on a dry weight basis)**Superscripts indicate significant differences betweenexpected and observed dietary contributionsFigure 2: Carbon and nitrogen dual isotope (‰) plot of whole bodies and muscletissue of white shrimp L. vannamei reared on feeding regimes consisting of differentproportions of formulated feed and live U. clathrata biomass. Muscle tissue valuesfor treatment 100U were estimated for day 28 from values in whole bodies. n= 2-4,mean values ±SD50 | InternatIonal AquAFeed | May-June 2013EXPERT T●PIC
  11. 11. tion of structural carbon and nitrogen when co-fed with formulated feed. However, the high amount of nutrients derived from the live macroalgae biomass in co-feeding regimes supplying more than 50 percent of macroalgae, was not reflected in a fast growth increase. This was possibly due to the restriction of other nutrients in this mac-roalgae species. Interestingly, shrimp under the co-feeding regime supplying 75 percent of formulated feed and 25 percent of live macroalgae biomass showed higher growth rates than animals reared only on commercial formulated feed, although the difference was not statistically significant. The low levels of energy, amino acids and fatty acids in the macroalgae biomass avail-able to shrimp, were compensated through high ingestion rates, which caused a higher incorporation of nutrients in shrimp tissue. On the other hand, it is very likely that the carbohydrates and lipids supplied by the formulated feed significantly contributed to the energy requirements of shrimp under the three co-feeding regimes.The importance of the natural productivity to shrimp grown in semi-intensively managed ponds has been widely documented. The systematic use of macroalgae in production ponds not only provides a significant nutritional supply to cultured organisms, but also offers substrate for periphyton growth and refuge for moulting shrimps. In addi-tion, it has been demonstrated that Ulva clathrata and other macroalgae species are efficient remov-ers of the main dissolved inorganic nutrients, hence maintaining good water quality levels in aquaculture ponds and effluents.Diverse isotopic techniques can be applied to elucidate the transfer of nutrients at the level of amino acids and fatty acids; therefore, future experimental assays might reveal what specific nutrients are contributed from the macroalgal biomass (or any other component of the natu-ral biota) and from the supplied formulated feeds. The loss of some nutritional properties that occurs in dietary ingredients that undergo drying (or freeze drying) has not been thor-oughly explained and future studies applying stable isotopes might shed some light on the differences observed when aquatic animals consume moist or dry dietary components.ReferencesBurtin, P. 2003. Nutritional value of seaweeds. Electron. J. Environ. Agric. Food Chem. 2:498–503.Cruz-Suárez, L.E., A. León, A. Peña-Rodríguez, G. Rodríguez-Peña, B. Moll, D. Ricque-Marie. 2010. Shrimp/Ulva co-culture: a sustainable alternative to diminish the need for artificial feed and improve shrimp quality. Aquaculture 301: 64–68.Gamboa-Delgado, J. 2013. Nutritional role of natural productivity and formulated feed in semi-intensive shrimp farming as indicated by natural stable isotopes. Reviews in Aquaculture In press.Gamboa-Delgado, J., M.G. Rojas-Casas, M.G. Nieto-López, L.E. Cruz-Suárez 2013. Simultaneous estimation of the nutritional contribution of fishmeal, soy protein isolate and corn gluten to the growth of Pacific white shrimp (Litopenaeusvannamei) using dual stable isotope analysis. Aquaculture 380-383: 33-40.Gamboa-Delgado, J., A. Peña-Rodríguez, L.E. Cruz-Suárez, D. Ricque D. 2011. Assessment of nutrient allocation and metabolic turnover rate in Pacific white shrimp Litopenaeus vannamei co-fed live macroalgae Ulva clathrata and inert feed: dual stable isotope analysis. J. Shellfish Res. 30: 1–10.Moll, B. (Sinaloa Seafields International). 2004. Aquatic surface barriers and methods for culturing seaweed. International patent (PCT) no. WO 2004/093525 A2. November 4, 2004.Villarreal-Cavazos D.A. 2011. Determinación de la digestibilidad aparente de aminoácidos de ingredientes utilizados en alimentos comerciales para camarón blanco (Litopenaeus vannamei) en México. PhD Thesis. Universidad Autónoma de Nuevo León, Mexico. InforMatIon:Julián Gamboa-Delgado PhDTel: +52 81 8352 6380Email: julian.gamboad@uanl.mx52 | InternatIonal AquAFeed | May-June 2013EXPERT T●PIC20thAnnual Practical Short Course onAquaculture Feed Extrusion,Nutrition, & Feed ManagementSeptember 22-27, 2013For more information, visit contactDr. Mian N. Riazmnriaz@tamu.edu979-845-2774Hands-On ExperienceTexas A&M University in College Station, Texaso various shaping dies (sinking, floating, high fat),coating (surface vs vacuum), nutrition, feedformulation, and MUCH MORE!Extruding Aquaculture Feedso 30+ lectures over a widevariety of aquacultureindustry topicso one-on-one interaction withqualified industry expertso at the internationallyrecognized Food ProteinR&D Center on the campusofo discussion and live equipment demonstrationsfollowing lectures on four major types of extrudersalso stimulate digestive enzyme production (Cahu et al. 1998).Production of microalgaeDespite the many advantages of microalgae, their wider use is hampered by difficulties in culturing, storage, and high costs. Microalgae culture can consume a significant fraction of the resources of a hatchery, and requires special equipment, skilled labour, and a large alloca-tion of space that is unproductive during the seasons when live feeds are not needed. Low-cost open-pond culture methods carry high risks of contamination and culture failure due to the impossiblity of tightly con-trolling culture conditions, and the most highly prized high-PUFA strains such as Isochrysis and Pavlova require indoor culture. It is very difficult to synchronize microalgal production with live feed requirements to prevent feed shortages or wasteful overpro-duction, and it is difficult to accurately dose algae cultures directly into live feed cultures. If the algae are harvested and concentrated, the tightly-packed cells can deteriorate rapidly in refrigerated storage. Some microalgae have been freeze- or spray-dried, but dried cells are subject to protein denaturation, and when they are rehydrated the leaching of water-soluble substances can rapidly deplete their nutritional value, as with other dry feeds. Microalgae concentratesThe best solution to these problems can be the use of commercially-available refrigerated or frozen algae concentrates or ‘pastes’ (Guedes & Malcata 2012, Shields & Lupatsch 2012). These products, which are actually viscous liquids, have proven to be effective feeds for rotifers, Artemia, shellfish and other filter-feeders, as well as for greenwater applications. In products formulated to provide a long shelf-life, the concentrated microalgae are suspended in buffer media that pre-serve cellular integrity and nutritional value, although the cells are non-viable. When concentrates with well-defined biomass densities are employed, the algae can be accurately dosed into live feed cultures with a metering pump, and non-viability confers the advantage that the products pose no risk of introducing exotic algal strains. The best refrigerated products typi-cally have a shelf-life of 3-6 months, and frozen products several years. This means that a reliable supply of algae can be kept on hand, available for use in any season or if an unexpected need arises. Algae costs become predictable, and often prove to be less than on-site production when total production costs and inefficiencies are accounted for.Although costs of liquid algae concen-trates are higher than for dried algae or formulated feeds, they offer all the nutritional advantages of live cultures. The nutritional quality of live feeds can be no better than the food sources used to produce them. Success of early larvae is so critical to the success of a hatchery that even a relatively small improvement in survival or growth rate can yield great benefits.OutlookLive feeds remain indispensable for larviculture of many fish. Although micro-algae are among the costliest food sources used to produce live feeds, their many advantages justify the cost for hatcheries producing high-value fish. Research contin-ues to better characterise the nutritional properties of various algae strains and to optimise algae production technologies. We can anticipate that introduction of novel algae strains and nutritionally-opti-mised combinations of strains, along with improved feeding protocols, will ensure that microalgae remain the food of choice for production of the highest-quality live 2013 | InternatIonal AquAFeed | 15FEATURENaturally aheadMYC OFIXMycotoxin RiskMan a g e MentMycofix®More protective.Mycotoxins decrease performance and interferewith the health status of your animals.Mycofix®is the solution for mycotoxin risk
  12. 12. AQUAFEED6 ISSUESInternational Aquafeed is published six times a year, bringing you in-depth features, industry news, events, book reviews and more. As well as your personal copy delivered direct to your address, subscribers to International Aquafeed also receive a free copy of the International Aquafeed Directory worth UK£85. For more information please visit our website. For a complimentary trial issue, please contact the circulation & subscriptions manager - Tuti Tan - Email: AQUAFEED DIRECTORYThe International Aquafeed Directory was launched in 1997 as an easy to use publication for manufacturers of fish feed to source suppliers. It evolved to become a practical guide to plant and materials available throughout the world.It is one of the most comprehensive information sources specifically designed to identify all aquafeed ingredients, raw feedstuffs, feed additive micro-ingredients, production machinery and plant and equipment available on the world market.£69 Recieve six issues of International Aquafeed magazine+ The International Aquafeed Directory & Buyers Guide16INTERNATIONAL AQUAFEED DIRECTORY 2012/13SCIENCE DFO SCIENCE SCISaltwater mariculture-aquaculture inQuebec may soon welcome a newarrival: the Spotted Wolffish, athreatened and little-known species thattastes delicious.In Quebec, commercial fish farmscurrently limit themselves to farmingfreshwater fish, while the maricultureindustry has focused until very recentlyon molluscs. In other parts of the world,saltwater fish farms are located right inthe ocean. Doing so significantly reducesfarming costs and makes themprofitable. In Quebec, installingaquaculture equipment in the ocean is adicey prospect because of ice cover inwinter. Previously, experiments withfarming saltwater fish in tanks revealedthe need for technical expertise as wellas the high cost of production. Today,however, research advances are showingthe potential of the Spotted Wolffish.This new mariculture candidate wasfirst noticed in the early 2000s. At thetime, teams from the Maurice-Lamontagne Institute in Mont-Joli,Quebec, collected their first SpottedWolffish as part of the research projectsthey were conducting with theUniversité du Québec à Rimouski andthe Quebec ministry of agriculture,fisheries and food.First of all, the Spotted Wolffish is afish that adapts well to the conditions itis kept in and is easy to domesticate. Itdevelops quickly at very lowtemperatures and is not very sensitive tochanges in the salinity of the water.Spotted Wolffish can be farmed in highdensities, something that is crucial forthe profitability of an aquacultureoperation (see Figure 2). As well, eventhough the Spotted Wolffish does notreproduce spontaneously in captivity,new generations can be produced everyyear using captive broodstock. And let’snot forget another important quality thisfish possesses: it tastes great.Aside from these obvious advantages,it is important to find out how thisspecies grows in captivity so that itspotential benefit to Quebec’s aquacultureindustry can be properly assessed. Forthat reason, Denis Chabot, a researcher atthe Maurice-Lamontagne Institute, wasapproached by the Société dedéveloppement de l’industrie maricole(SODIM) to carry tests using water tanks.rwadwcaLedetheTof fde GMau200theshandreseacondthoseoperacompaand Ihave bcommeyearsMont-JoslightlyNorwayconsiderspecies;Maurice-some rooFeedingchallengesin farmecommerciaintended fomodified. Twolffish thato develoResearchersoffers enougneeds of thethe feed doebottom of thewhen it comraised in highFarming saltwater fish inThe Spotted Wolffish showFigure 2: Spotted Wolffish in farming tankPhoto: Arianne Savoie, Fisheries and Oceans Canadapg16_DFO_wolffish.qxd 24/8/12 12:30 Page 16
  13. 13.• See the full issue• Visit the International Aquafeed website• Contact the International Aquafeed Team• Subscribe to International AquafeedThey are what they eatEnhancing the nutritional value of live feedswith microalgaeControlling mycotoxins withbindersUltravioletwater disinfection for fishfarms and hatcheriesNiacin– one of the key B vitamins for sustaininghealthy fish growth and productionVolume 16 Issue 3 2013 - mAY | Ju NeINCORPORATINGfIsh fARmING TeChNOlOGyThis digital re-print is part of the May | June 2013 edition of InternationalAquafeed magazine. Content from the magazine is available to view free-of-charge, both as a fullonline magazine on our website, and as an archive of individual features onthe docstoc website.Please click here to view our other publications on purchase a paper copy of the magazine, or to subscribe to the paperedition please contact our Circulation and Subscriptions Manager on the linkabove. INFORMATION FOR ADVERTISERS - CLICK HERE