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EXPERT T●PIC EXPERT TOPICCOBIA Welcome to Expert Topic. Each issue will take an in-depth look at a particular species and how its feed is managed. 50 | InternAtIonAl AquAFeed | March-April 2013
EXPERT T●PIC 1 3 2 4 China1The vast majority of the world’s cobia is pro-duced in China. In fact in 2004, the country produced 80.6 percent of global exports according to the FAO. However, despite this, there is little available information on cobia feeds or farming strategies used by Chinese farmers. Taiwan USA 3 4 Vietnam2 Taiwan is one of the pioneers of cobia Eighty-five percent of seafood in the USA is import- aquaculture. Initially broodstock fish ed but there is burgeoning interest in increasing In 2008, Vietnam produced 1,500 tonnes of were caught from the wild but in the domestic aquaculture production. Cobia is a promis-cobia, making it the third largest producer 1990s, the country became the first in ing candidate for aquaculture production due to its behind China and Taiwan. the world to successfully spawn cobia. rapid growth rate and good flesh quality. The first One of the largest cobia operations in the By 1997, the technology and know-how aquaculture research on the species was noted in country is run by Marine Farms Vietnam, a was in place to raise sizeable quantities 1975 in North Carolina, USA. Cobia eggs were subsidiary of Marine Farms ASA, Norway. The of cobia. Today, broodstock are taken collected off the coast and raised in a rearing trial. company has a shore base facility, hatchery site from grow out cages and transported Like Taiwan, there have also been success-and ten sea sites, which range from 20 m to to onshore ponds to spawn. Juvenile ful spawning efforts on the USA. 32 m in depth. The farms, which are located cobia (1.5-2 years) is sent to grow out While the early production cycle in Taiwan north of Nha Trang, produce more than 1,500 ponds, nearshore cages or offshore favours outdoor ponds, juvenile cobia in the USA metric tons of cobia per year, with the capacity cages. tend to live in fibreglass tanks. According to the to produce more than 6,000 tons if needed. According to FAO data, cobia pro- FAO, these tanks are either operated as recircula- Not content with only Vietnamese ducers in Taiwan use both floating tion systems, flow-through or a combination of both. cobia production, Marine Farms also has a and sinking pellets comprised of 42-45 Research efforts have focused on extending the cobia operation in Belize which has been percent crude protein and 15-16 per- cobia spawning season with the aim of reaching growing cobia in offshore cages since cent lipid. The FCR is approximately year-round egg production. To date, eggs have been 2006. 1.5:1. successfully fertilized during 10 months of the year. March-April 2013 | InternAtIonAl AquAFeed | 51
EXPERT T●PICDeveloping found (Briggs, 1960; Collette, 1999; Benetti et addressed and resolved at this juncture are al., 2008). Cobia are recognised for their fast related to feeds and nutrition. ecologically efficient, growth, excellent meat quality, and have been At the present time, feeds represent the intensively farmed since the 1990s (Liao et most expensive item of the production costs economically viable al., 2004; Benetti et al., 2007). for cobia, and the inability to provide a sustainable, high-quality feed that meets the and nutritionally These characteristics, along with excellent energetic and nutritional requirements of meat quality and good market demand and these fast growing fish continues to elude adequate feeds for price, raised enormous interest in commer- producers. Top quality diets with high inclu- cial aquaculture development of this species. sion levels of fishmeal and fish are avail-cobia Rachycentron Indeed, while cobia was a little known candi- able but costs are prohibitively high from date species for aquaculture about a decade both ecological and economical perspectives. canadum ago, today it has established itself as a top Therefore, the collective goal of researchers, quality cultured marine fish tropical/subtropi- feed manufacturers and producers is to for-The University of Miami and other USinstitutions have teamed up with feed cal in Asia and the Americas. mulate, develop and manufacture ecologically manufacturing companies, producers Technology for reliable broodstock spawn- efficient and economically viable diets that and the American Soybean Association ing and mass production of fingerlings has will meet the nutritional requirements of this to develop competitive practical feeds been mastered at the University of Miami species. This review summarises these efforts.for this emerging aquaculture species Experimental Hatchery (UMEH) and other The evaluation of feed ingredients is crucial private companies and government institu- to nutritional research and feed development by Jorge A Suarez, Carlos Tudela, Drew tions around the world. However, while the for aquaculture species. In evaluating ingredi- Davis, Matthew Taynor, Lindsay Glass, fundamental technology for cobia production ents, there are several important points that Ron Hoenig and Daniel D Benetti from egg to market is in place (Liao et al., must be understood to enable the judicious C 2004; Benetti et al., 2008; 2010), many years use of a particular ingredient in feed formula- obia is the only member of the of research and development are still needed tion (Glencross et al., 2007). The determina- family Ranchycentridae. It is a to refine the culture process, allowing cobia to tion of nutrient digestibility is the first step in tropical and subtropical species develop on an industrial scale, especially at the evaluating the potential of an ingredient for widely distributed worldwide grow-out stage. use in the diet of an aquaculture species (Allan (Briggs, 1960; Shaffer and Nakamura, 1989; Those working with the species both at et al., 2000). Ditty and Shaw, 1992; Benetti et al., 2008), the R&D and production concur that the A constraint for the expansion of cobia aqua-except in the eastern Pacific, where it rarely most crucial remaining roadblocks to be culture is the availability of high quality formu- 52 | InternAtIonAl AquAFeed | March-April 2013
EXPERT T●PIClated diets which reduce or eliminate fishmeal Although nutritional principles are similar acids derived from triglycerides constituting protein. Suitable replacements are often of plant for all animals, the amounts of nutrients the major energy source for muscle in almost origin, but the evaluation of nutrient digestibility required vary among species. There are about all animals. They are also key components of in new ingredients should be an initial step in 40 essential nutrients in fish diets (Akiyama et cellular and subcellular membranes (phos-evaluating its potential for fishmeal replacement. al., 1993). According to Tacón (1989), nutri- pholipids, sterols, etc.). Performing functions Therefore, the apparent digestibility coefficients tional requirements in the diet of all cultured as biological transporters in the absorption of (ADCs) of protein and amino acids of a novel aquatic species may be categorized under five fat-soluble vitamins are precursors of pros-variety of non-GMO soybean meal, Navita™, different nutritional groups: proteins, lipids, taglandins and hormones (Fenucci and Haran and an industry standard soybean meal (defatted carbohydrates, vitamins and minerals. 2006). For juvenile cobia, the lipid require-soybean meal/roasted solvent-extracted), were ment was estimated at 5.76% (Chou et al., evaluated at University of Miami for juvenile Major nutrient requirements for 2001). Wang et al. (2005) used three isopro-cobia, Rachycentron canadum. Results indicated juvenile cobia teic diets (47% protein) with three lipid levels that the Navita™ is highly bio-available to cobia, Protein: One of the most important nutri- (5%, 15% and 25% dry matter). The authors as ADCs for protein and amino acids obtained ents in the diet of marine fish is protein. This found no significant differences in growth for this ingredient were significantly higher for is attributed to two factors, which are the between the cobia (7.7 g) fed diets containing nearly every analysed component of the feed high cost of the ingredient and the organisms’ 5 percent and 15 percent lipids. However the than the ADCs of the conventional soybean high protein nutritional requirement. Excess cobia fed 25 percent lipid had a significant meal. ADCs crude protein were 81.8% and protein not only increases feed costs but it reduction in daily diet consumption, suggest-68.5%, respectively, for Navita™ and conven- also increases the excretion of nitrogen into ing that lipid levels above 15 percent reduced tional soybean meal. Similarly, ADCs of selected the environment. The first article used to growth due to decreased feed consumption.amino acids ranged from 68.3-108.6% for the determine protein requirements in cobia was Carbohydrates: Because cobia commer-Navita™ meal, whereas the same coefficient that of Chou et al. (2001), who determined cial feeds contain starch and cereal products, ranged from 41.4-97.8% for the conventional by regression analysis, a protein requirement related research on carbohydrate require-soybean meal. Findings from the present experi- of 44.5%. Craig, Schwarz and McLean (2006) ments are very important. Schwarz et al. ment highlight the potential of Navita™ as a conducted a factorial study with two levels of (2007) suggests that cobia are able to use suitable FM replacement in cobia diets and crude protein (40% and 50%) and three lipid up to 360g/kg-1 of dietary starch from low should help to maximize cobia growth while levels (6%, 12% and 18%). The authors found molecular weight carbohydrate such as dex-minimising the excretion of fish metabolites a significant difference in feed efficiency of 7.4 trin. Webb et al. (2009) determined that (Davis et al., 2012). g cobia fed with the lowest level of protein. cobia can use carbohydrates to levels of On the contrary, when the authors used 340g/kg-1 (dry diet) with an optimum energy Reviewing cobia nutrition larger cobia (49.3 g) no significant differences protein of approximately 34mg protein kJ-1 In their thorough review of cobia nutri- in feed efficiency were found between the metabolisable energy.tion, Fraser and Davies (2009) pointed out different levels of protein. Vitamins: Vitamins are nutrients necessary the importance of paying special attention to Amino acids: The nutritional value of a for growth, health, and reproduction of organ-the amino acid requirements when replacing protein diet is influenced by the composition isms and are required in very small amounts fishmeal with alternative protein sources. Chou of its amino acids. For this reason, the protein in fish diet. Mai et al. (2009) determined the et al. (2004) mentions that methionine is the to be used in practical diet formulations must requirements of choline in juvenile cobia. The primary limiting amino acid replacement in be based on digestible amino acid profile requirement determined by ‘broken line’ for studies of fishmeal with soybean meal. Lunger and quantitative amino acid requirements weight gain was 696 mg/kg-1 choline diet as et al. (2007) found that the amino acid taurine in the targeted species. In cobia, studies of choline chloride. Unfortunately there is not supplementation at a level of 5g kg1 dry weight, amino acid requirements are limited, only enough information on the requirements for increased weight gain and feed efficiency in two of the ten amino acids have been con- vitamins and minerals in Cobia.cobia fed diets with high levels of plant protein. sidered essential (Wilson 2002). Zhou et al. Fraser and Davies (2009) conclude that (2006) determined methionine requirements Future research areasnutritional studies on cobia are limited because in juvenile cobia. The authors state that for For the future we propose the following most have been conducted using juvenile fish maximum growth and lower feed conversion research in the area of cobia nutrition:with much lower weights than harvestable ratio, the requirement of methionine is 1.19% • Determine nutritional requirements at size. The cobia commercial weight is between (dry diet) in the presence of 0.67% cysteine, different sizes classes4 and 10 kg; however nutritional require- corresponding to 2.64% dry weight of dietary • Further requirements of amino acids, ments have only been examined in juvenile protein. vitamins and mineralsfish weighing 50 g. Although differences in the For lysine, Zhou et al. (2007) determined • Continue research replacement of fish-requirements were minimal, it would still have the requirements in juvenile cobia. The result meal and fish oil to alternative sources a high important commercial impact, especial- for lysine requirements were 2.33% and of protein and lipidly considering protein and lipids are the major 5.30% dry weight of dietary protein. These • Complement existing information on dietary components in fish diets. The accuracy values of methionine and lysine are in accord- digestibility and energy balance of pro-of the nutritional requirements would not ance with the requirement values of other tein ingredients of plant and animal only have a positive economic impact on the important fish species in aquaculture (Wilson originindustry, but also decrease the environmental 2002). Recently, Ren et al. (2012) determined • Monitoring the quality of commercial pollution by decreasing nutrient loading in the the requirements of arginine on the basis of feeds, used by the industryaquatic ecosystem. As reviewed by Welch et SGR and FER. The optimal dietary arginine • Implementation of management al (2010), the importance of the responsible requirements of juvenile cobia were estimated practicesuse of natural resources such as fishmeal, to be 2.85% of the diet and 2.82% of the diet, In conclusion, the collaborative effort of fish oil and vegetable crops to ensure the respectively. researchers, feed manufacturers and produc-environmental sustainability of aquafeeds is Lipids: Lipids are an important source of ers are driving steadfast progress towards well recognised. highly digestible energy, in particular, free fatty developing practical and economical diets for March-April 2013 | InternAtIonAl AquAFeed | 53
EXPERT T●PIC Benetti, D.D., M.R. Orhun, I. Zink, F. G. Cavalin, B. Sardenberg, K. Palmer, B. Denlinger, D. Bacoat and B. OHanlon. 2007. Aquaculture of cobia (Rachycentron canadum) in the Americas and the Caribbean. Pages 57-78. In: I C. Liao and E.M. Leaño (editors) In: Cobia Aquaculture: Research, Development and Commercial Production. Asian Fisheries Society, Manila, Philippines, World Aquaculture Society, Louisiana, USA, The Fisheries Society of Taiwan, Keelung Taiwan, and National Taiwan Ocean University, Keelung, Taiwan. Benetti, D.D., 2008. Cobia aquaculture expanding in the Americas and the Caribbean. Global Aquaculture Advocate 1(2): 46-48 Benetti, D.D., B. O’Hanlon, J.A. Rivera, A.W. Welch, C. Maxey and M.R. Orhun 2010. Growth rates of cobia (Rachycentron canadum) in open ocean cages in the Caribbean. Aquaculture 302: 195-201 Briggs, J.C., 1960. Fishes of world- wide (circumtropical) distribution. Copeia 3,171-180. Catacutan, M.R. & Pagador, G.E. ,2004. Partial replacement of fishmeal by defatted soybean meal in formulated diets for the mangrove red snapper, Lutjanus argentimaculatus (Forsskal 1775). Aquacult. Res., 35, 299–306. Chou R.L., Su M.S. & Chen H.Y.,2001. Optimal dietary protein and lipid levels for juvenile cobia (Rachycentron canadum). Aquaculture193,81-89. Chou R.L., Her B.Y., Su M.S., Hwang G.,WuY.H. & Chen H.Y.,2004. Substituting fish meal with soybean meal in diets of juvenile cobia Rachycentron canadum. Aquaculture 229, 325-333. Collette, B.B., 1999. Rachycentridae. In: Carpenter, K.E., and Niem, V.H. (Eds.), The Living Marine Resources of the Western Central Pacific. Volume 4. Bony fishes part 2 (Mugilidae to Carangidae). FAO. Rome.cobia at all developmental stages. Government industry is and will continue to benefit all Craig S.R., Schwarz M.H. & McLean E., 2006. support as well as interest and funding gener- stakeholders, from producers to consumers. Juvenile cobia (Rachycentron canadum) can utilize ated by American Soybean Association and a wide range of protein and lipid levels without its various affiliated groups have been of References impacts on production characteristics. Aquaculture paramount importance in advancing knowl- 261,384-391. Allan, G.L., Parkinson, S., Booth, M.A., Stone, D.A.J., edge and technologies the field. The industry Rowland, S.J., Frances, J., Warner-Smith, R., 2000. Davis, D., Suárez, J., Buentello, A., Benetti, is much further ahead than it was about a Replacement of fish meal in diets for Australian D (abstract accepted in October 2012). decade ago. It is recognised that enhanced silver pech, Bidyanus bidyanus: I. Digestibility of Apparent digestibility coefficients of knowledge and better nutrition are allowing alternative ingredients. Aquaculture 186, 293-310 protein and amino acids of a novel non-cobia aquaculture production to continue to GMO variety of soybean meal for juvenile Akiyama D., 1993. El uso de productos a base de expand exponentially worldwide while mov- cobia, Rachycentron canadum; Abstract, oral soya y de otros suplementos proteicos vegetales en ing away from inadequate diets and trash fish. presentation, 2013 Aquaculture America alimentos para acuacultura. Memorias del Primer The development of an ecologically efficient Conference, World Aquaculture Society, Simposium Internacional de Nutrición y Tecnología Februar y 21-25, Nashville, Tennessee.and economically viable cobia aquaculture de Alimentos para Acuacultura, pp. 257-269. 54 | InternAtIonAl AquAFeed | March-April 2013
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