Aquaculture Scoop October 2015

Aquaculture Scoop is a magazine for aquaculture professionals worldwide

Issue 10 / October 2015 Pelleting presses Amandus Kahl

Mixing Technology Feed production process

Dietary Acidifiers

Nucleotides

Dietary Potassium Diformate (KDF)

Metabolism and nutrition

Expo list Top events related to aquaculture from around the world, on p. 26

27 GLOBAL EVENTS: We list the world’s top industry events. PAGE 26

Dietary Acidifiers

Organic acidifiers in salmonid nutrition FLAT BED PELLETING PRESSES

Amandus Kahl Read more on page 04

Published by Nisa Media Ltd www.aquaculturedirectory.co.uk Find us on Facebook and Twitter www.twitter.com/aquaculturedire

ANDRITZ OptiMix paddle mixer p.9

Bio-security in Aquaculture p.20

Aquaculture will supply two-thirds of global fish consumption by 2030

Sign up to our FREE weekly newsletter Email us at seafood@nisamedia.com Source: World bank report

Editor’s Comment

Welcome to the October issue of Aquaculture Scoop

Visit us online at

www.aquaculturedirectory.co.uk

Pelleting presses Welcome to the latest issue of Aquaculture Scoop.

In this issue we take a look at Pelleting presses with insight from Amandus Kahl. We learn about Mixing Technology in the feed production process and how Dietary Acidifiers, specifically KDF are used in Salmonid Aquaculture. Nucleotides are featured in a report from Chemoforma and we also look at interesting and extensive information on best practice in the industry from Stephen Newman Ph.D., CEO of AquaInTech Inc. USA. With many events coming up why not visit our website and download the latest 2015 wall planner.

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Amandus Kahl

Mixing Technology Feed production process

Dietary Acidifiers Dietary Potassium Diformate (KDF)

Nucleotides Metabolism and nutrition

Best Practice AquaInTech Inc. USA

Published by: NISA Media Ltd 14 Clarke Way Cheltenham GL50 4AX United Kingdom

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Martin Little Email: mlittle@aquaculturedirectory.co.uk

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Aquaculture Scoop October 2015

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Pelleting presses

More information: Amandus Kahl Email: info@akahl.de Web: www.akahl.de

KAHL flat die pelleting presses, robust and powerful for producing fish feed Pelleting of fish feed is a simple and extremely competitive variant of the fish feed production. Particularly in the production of farm-made aquafeeds in Asia and Africa, there is a growing demand. Since local raw materials can be used for farm-made feeds, simple and inexpensive processes are possible for increasing the nutritional value for fish and crustaceans. While salmonids benefit from increased starch modification and improved feed conversion ratio due to the extrusion of fish feed, other species of fish do not need this type of feed treatment. So there are no disadvantages in carp production by feeding this fish species on pelleted fish feed.

Due to the metabolic digestion, only a marginally higher feed conversion ratio must be expected in the production of tilapia and catfish.

Figure 1: Pan grinder head and flat die

The development and design of corresponding process lines can ensure this, particularly with regard to the digestibility, the removal of toxic substances and an improved palatability. Therefore, pelleting of fish feed with the flat-die press offers considerable advantages.

For decades (more than 70 years) KAHL pelleting presses have been applied successfully for compacting organic products such as compound feed, bran, dried beet pulp, dried algae and others.

The product is pressed through a die by pan grinder rollers, formed into endless strands, and then cut to the desired particle length by means of knives. The process lines are constantly developed in order to improve their capacities and economic efficiency. KAHL pelleting

Aquaculture Scoop October 2015

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Pelleting presses

presses are particularly appropriate for products which are difficult to pellet.

The current production range of KAHL presses consists of 14 different sizes Die diameter Drive motor Roller diameter Pellet diameter Output

175 – 1,500 mm 3 - 630 kW 130 - 450 mm 2 - 30 mm 2 kg/h – 40 t/h

The small presses are driven by slip-on gears, the big presses by low-noise and low-wear worm gears with preceding belt drives.

A convincing technology 1. The product is fed by gravity, so there is enough room at high capacities. The large pelleting chamber avoids blockings.

2. The low roller speed of approximately 2.5 m/s ensures a good deaeration of the product, therefore is a clean and smooth running possible.

7. Quick die changing increases the availability of the complete plant and the easy adjustment of the pressing load allows a simple process running.

larly with materials having a low bulk density, is excluded. For material feeding and acceptance by the pelleting tools a large press interior is available.

8. High Liquid variations in the product are permissible.

Pan grinder head

9. Mixtures with high levels of fat can be effectively pelleted.

10. Each pelleting press is tested before supply under full-load simulation.

Material feeding The material is directly fed to the press vertically from above by gravity without passing any deflectors and without the use of mechanical aids (forced feeding).

Thus the danger of blocking or bridging due to inadvertent compaction, particu

The pan grinder head forms one unit comprising roller axles and rotating pan grinder rollers. Number, diameter, width, shape (cylindrical or conical), and surface of rollers are selected to best suit the material to be pelleted (see figure 1).

Materials with a low bulk density are handled with fewer rollers to provide more space. The circumferential roller speed of 2.5 m/s is relatively low which makes it easier to force the material between the rollers and the die. Furthermore the material can be deaerated more easily, the risk of roller slip is reduced and the press can operate

Figure 2: Distamat control system

3. As a result of the low speed and the no forced feeding, the press noise is below 70 dbA. 4. The thick product layer between the pan grinder rollers and the large die surface results in a high throughput, even in case of products which are difficult to pellet.

5. The roller gap can be adjusted during operation, thus the pellet quality can be controlled.

6. Permanently lubricated roller bearings with special seals prevent the product being pelleted from contamination by lubricating grease as well as grease losses. For this reason there is a long service life at a low grease consumption.

Aquaculture Scoop October 2015

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Pelleting presses

under a noise level lower than that of the drive motor.

Distamat The hydraulic pan grinder head adjusting system makes it possible to optimise the distance between rollers and die during operation. The thickness of the material layer can therefore be influenced in such a way that the most economic press capacity is achieved.

Thus it is possible to optimise the quality

of the fish feed and crustaceans pellets.

Press output, pellet quality, security of operation, service life of the die and rollers and availability of plant are thus considerably improved. The electronic control system keeps the value constant.

The hydraulic system in connection with automatic load control allows deblocking of engine while running. The Distamat system (see figure 2) determines the gap between the pan grinder rollers and the die after the assignment

of zero between pelleting press and measuring cylinder (the taring process).

For the gap measurement, a measuring cylinder is installed in the oil supply line of the hydraulic nut of the press. A displacement of the pan grinder head causes a displacement of the measuring cylinder. This is measured by a displacement sensor and processed as actual value by the control system. The displacement sensor emits a signal of 4-20 mA = 0-100 % to the control system. In the control system, this signal is calibrated in mm by means of a conversion factor.

The task of the Distamat is to maintain the gap between pan grinder roller and die constant according to a preset set point value, independent of the product quantity.

The gap is indicated in mm for an easier understanding. The values of the gap are indicated as repeatable values under the same measuring conditions - though they are no real measuring values. Deviations between the indicated gap and the measured values are possible due to the indirect measuring method. A constant gap between pan grinder roller and die is an essential prerequisite for the pellet quality as well as a stable operation. The resulting pressure is due to the load of the machine (modification of throughput, of humidity, or of product). As it keeps the contact between pan grinder roller and die to the technically necessary minimum, the Distamat minimises the wear.

Figure 3: Flat die and varies pellet feed products

Aquaculture Scoop October 2015

In addition, several safety functions for the pelleting press are realised using the Distamat. For the functioning of the Distamat the correct mechanical assembly of the pelleting press according to the operating instructions, the tightness of the unit, as well as a good condition of the wear parts are basic prerequisites.

Functioning of the hydraulic pan grinder roller adjusting system: on the left in the rest position, on the right in working position.

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Pelleting presses

Dies Die thickness plus the number, shape, and diameter of the holes as well as the roller track width can be varied according to the material to be processed, as you can see in figure 3. A high specific press output with low energy consumption per unit is among other things greatly influenced by the retention time of the material inside the effective bores. The specific roller track area varies between 25 and 30 cm² per kW of the installed power depending on the intended use and requested material compaction. Only with large specific perforated die areas can the installed power be completely converted into throughput.

Shearing effect The shearing forces produced by the pan grinder rollers when running on the product layer between rollers and die result in a better pre-compaction, less crumbling and drilling of the material, better intake characteristics, shorter length of the effective bores as well as smoother, harder, and tougher pellets with the same power consumption. Conical rollers can be used for materials whose nature does not allow them to be subjected to additional shearing forces or which causes excessive wear on the die. Due to the direct material feeding, the large press interior, and the shearing effect of the rollers even very coarse material can be processed. With some products, e.g. waste, one size reduction stage can be saved by operating the existing grinding plant using a bigger mesh size. The net result is a saving of energy, a reduction in investment costs, and a simplified sequence of operation.

grinder head is held in place by the adjustable hydraulic nut. Changing dies is therefore very easy and rapid, because except for the hydraulic nut no screws or clamps need to be loosened.

The pan grinder head and die can easily be lifted by means of an electric chain hoist and be replaced without any need to clean the interior.

Automatization for optimum products Switch and control panels for all plant sizes are designed, built, and installed

by KAHL. Our electrical engineers develop custom-made application software for ensuring a high degree of operating safety and efficiency.

The EAPR is the pelleting press control system for an optimum, automatic operation of the flat die pelleting presses of the company KAHL. It consists of a local control cabinet with a graphic operator panel (OP) and an S7-PLC by Siemens as central components. The EAPR controls and regulates all the relevant process parameters.

• Optimum operation of the pelleting press • Low manpower requirements • High availability due to the use of proven quality components • Optional field bus system saves installation work • DISTAMAT for continuous adjustment and control of the roller gap (option)

Product tests can be carried out in the Kahl pilot plant The Amandus Kahl test departments are responsible for the development of new processes and machines. They have extensive pilot plants with laboratory, produce on machines, and measuring equipment for the most important process stages of the conditioning technology. To complete the fish feed production line there is the new commissioning of the single shaft extruder and the new KAHL vacuum coater.

In the last decades more than 10,000 products have been pelleted successfully in the KAHL pilot plant. There is nearly nothing - that can’t be pelleted.

Change of pelleting tools The dies are supported on the full circumference of the press case. The pan grinder head is seated loosely on the main shaft and is connected to the latter by feather keys. From above the pan

Aquaculture Scoop October 2015

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Mixing Technology

Mixing technology - An important step in the feed production process 6000g per day and it is equally as important that the formula is mixed properly, so the pig gets exactly the ingredients planned for it to grow

The primary steps in the feed pelleting processing are: • • • • • • • • •

Dosing/weighing Grinding Mixing Conditioning Expansion Pelleting Cooling Sifting Coating

Prior to the mixing process, the feed ingredients have been weighed and grinded and the vitamins and minerals have been added to the feed compound.

The next step is then for all the ingredients to be mixed together.

Mixing technology

• Mixing both formulas demands for high accuracy, as the chicken formula contains as many ingredients as the formula for the grown pigs • Good mixing ensures planed growth of your animals Especially, speed and quality are two qualities customers prioritize. A good mixer should provide booth fast and efficient mixing. Furthermore, it should be easy to clean and maintain.

Mixer qualities and important principles

Basically mixing (or homogenizing) means to transport the individual particles to an exact position in relation to other particles and thereby avoid segregation. It is very important to have all the ingredient mixed together properly to achieve a good feed pellet quality.

• Mixing is of enormous impotency and it is very important it mixes all particle sizes equally precise

Optimum mixing

• Failed mixing can result in slow grow of the animal

Optimum mixing of the feed ingredients will ensure uniform distribution of nutrients, vitamins and minerals, which will result in a homogeneous nutrient content in each feed pellet. Further, it will ensure optimum growth of the animals.

What is a good mixer?

There are many demands to the capabilities of a good mixer.

Aquaculture Scoop October 2015

• Many feed formulas contain different enzymes opening phosphors or in some cases to cover the phosphors

• It is very important that no and absolute no products are carried (cross contamination) from one formula to the next • A mixer needs cleaning as a routine

ANDRITZ proudly introduces the new OptiMix paddle mixer ANDRITZ is proud to introduce the new OptiMix paddle mixer to the market. The new mixer has shorter mixing time and the new patentable design features are unique for the market. The OptiMix has

• Too many or too few minerals or medicines can result in ill animals or even worse • A one-day old chicken consumes only 10g per day, but it still needs all planned ingredients to be in the feed for it to grow as planned • Even a full-grown pig consumes

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Mixing Technology

ANDRITZ is committed to a substantial R&D efforts in order to lead the industry in technological innovation. We are consistent in offering advanced products, so our customers will continue to see the benefits of buying our products.

a new improved design to improve its performance. It is three times faster than the old ANDRITZ mixer. Further, cables and other installations are hidden, making it easier to clean.

Key features: • • • • • • •

Self cleaning: preventing cross contamination between batches Ensures fast and efficient mixing Has a unique design: easy to clean and maintain Easy installation Easy access to liquid systems Double sealing of bottom damper Has a mixing quality with a Probability (p) > 25% equivalent to a CV < 5%

The ANDRITZ OptiMix is tested and verified by TI (Technological Institute) and MTSE (Micro Tracer Services Europe) by using the toughest test method described. We achieved a mixing probability of (p) > 25% within 75 seconds (Equivalent to CV < 5%).

Focus on research and development The new OptiMix paddle mixer is the result of dedication and hard work from our skilled R&D team. It is a key factor of our vision to keep providing the best quality machines to our customers that ensure easy production, cost efficiency and high-quality results.

Aquaculture Scoop October 2015

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YOUR INDUSTRY DIRECTORY Your aquaculture resource.

Aquaculture Directory is a business listing reference for aquaculture professionals worldwide. Covering all aspects from equipment to raw materials and including all suppliers and manufacturers working within the industry.

Bringing you the latest up-to-date relevant news, upcoming industry events, Universities and worldwide company contact information.

Visit us online at:

www.aquaculturedirectory.co.uk

Aquaculture Scoop October 2015

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More information:

Dietary acidifiers

Christian Lückstädt ADDCON, Bonn, Germany Email: christian.lueckstaedt@addcon.com

The use of organic acidifiers in salmonid nutrition – with special focus on dietary potassium diformate (KDF) General review of dietary acidifiers Dietary acidifiers have been used for decades and their effects are documented in many scientific publications.

Organic acids make a fundamental contribution to feed hygiene, as they suppress the growth of mould and bacterial pathogens, thus allowing better use of feed resources. Organic acids are natural by-products of microbial fermentation as well as occurring naturally in plants. They have been used for thousands of years as food preservatives. This is why the industry has found them a natural choice and public perception regards them as acceptable to optimise animal production.

A report from “Markets and Markets (2014) indicated that the Global market for feed acids in the segment “aquaculture” is estimated to reach 165 million USD in 2018. The report further stated that the global potential for dietary acidifier for fish and shrimp is on the rise. The expected compound annual growth rate is assumed to be more than 6.5% till 2018.

Early studies on the use of organic acids in fish diets included succinic and citric acids in diets for salmonids (Fauconneau, 1988). These included the partial substitution of protein (12%) by a single amino acid or an organic acid (succinic or citric) in rainbow trout (Oncorhynchus mykiss) diets. Trout which were fed the organic acid diets

Aquaculture Scoop October 2015

had lower voluntary feed intakes compared to the basal diets or to a diet supplemented with purified protein.

Data from the 1990’s obtained promising results of the use of dietary acidifiers in a number of salmonid species. The effect of the supplementation of commercial diets with sodium salts of lactic and propionic acid was tested in Arctic charr (Salvelinus alpinus) in brackish water at 8°C (Ringø, 1991). Fish fed the diet with 1% added sodium lactate increased in weight from about 310 g to about 630 g in 84 days, while fish fed diets without either salts reached a final weight of only 520 g (P<0.05). Inclusion of 1% sodium propionate in the diet however had a growth depressing effect compared to the control (P<0.05). The gut content from Arctic charr fed the sodium lactate supplemented diet contained lower amounts of water, energy, lipid, protein and free amino acids. It has been observed that charr feeding on high doses of commercial feeds, as under aquaculture conditions, have a tendency for diarrhoea. When charr fed on diets containing sodium lactate, diarrhoea did not occur, probably indicating much lower amounts of remaining nutrients and water in the gut. Furthermore, it was proposed that the growth promoting effect of dietary lactate in Arctic charr results from a relatively lower gastric emptying rate (Gislason et al., 1996).

Increased holding time in the stomach augments the antibacterial potential of the lactic acid salt and can have

therefore a larger inhibition effect against possible pathogenic bacteria (Sissons, 1989). The improved growth of the Arctic charr did not affect the chemical composition of the fish (Ringø et al., 1994).

Further studies on salmonids again included rainbow trout Oncorhynchus mykiss. The effect of organic acids on digestibility of minerals was tested in several studies. It was reported from pigs, that the inclusion of dietary organic acids enhances mineral absorption (Ravindran and Kornegay, 1993). Vielma and Lall (1997) reported the effect of dietary formic acid on the availability of phosphorous in such diets for rainbow trout. It was found that the apparent digestibility of phosphorous was significantly increased (P<0.05) in fish fed a diet containing 10 mL kg -1 formic acid.

More recent studies include experiments with rainbow trout fingerlings (de Wet, 2005, 2006), which were fed five experimental diets. Those diets consisted of a control diet, three diets containing 0.5, 1.0 and 1.5% of an organic acid blend (formic acid and its salts as well as sorbic acid) and a diet containing an antimicrobial growth promoter (AGP, 40 ppm Flavomycin). At the end of the trial, improvement in growth was observed with increasing level of organic acid inclusion. Inclusion levels of 1.0% and 1.5% resulted in significant

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Dietary acidifiers

improvement in the specific growth rate of the fish when compared to the control (P<0.05). The improvement was similar to what was achieved with AGP inclusion, when 1.5% of the acid blend was used. Fish fed the 1.5% acid blend, however, tended to have a lower FCR compared to the group with in-feed antibiotics.

Potassium diformate in Salmonid aquaculture The use of acidifiers in aquaculture diets is currently gaining more interest among commercial users and a wide range of different organic acids and salts have been tested so far (Lückstädt, 2008). Potassium diformate (KDF; traded as Aquaform® - Figure 1) in particular has been used widely in tropical and cold-water aquaculture, because of the high load of active ingredients as well as its stability and handling properties in extruded feeds.

In this respect, an intense study by Morken et al. (2011) showed that potassium diformate had a significant positive influence on physical parameters of extruded soy-based diets for Atlantic salmon (Table 1). This has also been confirmed in novel plant-based

Aquaculture Scoop October 2015

Figure 1: Electron-microscope image of potassium diformate particles ©WK Ng, University Sains Malaysia

diets for trout (Morken et al., 2010).

Here the authors found highly significantly (P<0.001) improved hardness, water stability and durability of trout diets supplemented with the diformate.

The former study indicated that the inclusion of KDF led to a significantly improved starch digestibility (58 vs.

62%), while the latter specified improved apparent digestibility of lipid, ash, protein and total amino acid (P<0.05).

Continued >

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Dietary acidifiers

Table 1: The effect of the interaction between KDF supplementation and extrusion temperature on physical quality of Salmon diets containing defatted soybean meal

Furthermore, dietary KDF counteracted the reactivity that had been induced by prior expander heat treatment, thereby improving digestibility of amino acids in ingredients that had been pre-treated at the highest temperatures (122°C). This has been supported by data from Morken et al. (2012), which showed that the in-vitro bioavailability of amino acids, released during the alkaline hydrolysis by salmon digestive enzymes is significantly enhanced from 18.7 mg to 25.3 mg.

*NC: Negative Control; Means with a different superscript in each row differ significantly (P<0.05) This has been confirmed by other data (Lückstädt and Schulz, 2008; Lückstädt and Kühlmann, 2009), where salmon, reared in fresh- and sea-water and fed on diets containing potassium diformate had significantly higher protein- and fat digestibility respectively.

Finally, it has been found (Storebakken et al., 2010) that the inclusion of dietary potassium diformate protects against heat-induced reduction of protein digestibility in a mixture of full-fat soy and wheat when used in extruded diets for Atlantic salmon. Here, addition of KDF (1.2%) prior to extrusion resulted in improved digestibility of amino acids.

Aquaculture Scoop October 2015

Table 2: Growth performance of Atlantic salmon fed with potassium diformate treated fish meal as protein source (126 days, sea water)

Means with a different superscript in each column differ significantly (P<0.05)

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Dietary acidifiers

Performance results in salmonids reveal that Atlantic salmon fed fishmeal enriched with 1.4% potassium diformate in their diet (CP 40%, CL 30%) tended (P=0.055) to have a higher specific growth rate compared to a negative control (Christiansen and Lückstädt, 2008). Furthermore, groups fed 0.8% and 1.4% potassium diformate fishmeal had a significantly better feed conversion and improved the uniformity of fish groups (Table 2).

Further trials with diformate in Germany, conducted over a period of 66 days in Rainbow trout, show the beneficial impact in this species (Lückstädt, 2010). Fish with an initial weight of 19.5 g were divided into two groups and fed 4 times a day with a commercial diet containing 43% CP and 23% CL. The treated group contained

0.3% of the diformate, whereas the control group did not contain any dietary acidifier. At the end of the trial, a considerable improvement in the FCR, as well as a reduction in the mortality was noticed. This led to an improvement in the Fish Productivity Index (Lückstädt and Kühlmann, 2011), a function of weight gain, survival and FCR, by more than 11% (Table 3).

Similar findings have been reported during commercial use of 0.3% KDF in trout farms in Colombia, where, in particular, a significant reduction in mortality of at least 50% was noticed during the transfer of fingerlings to the grow-out sites, supporting other data from around the world on the anti-bacterial impact of potassium diformate against various gram-negative bacteria in various fish species (Ramli et

Table 3: Performance parameter of Rainbow trout fed with or without 0.3% diformate

al., 2005; Ng et al., 2009; Abu Elala and Ragaa, 2014). Further studies on survival rates have been undertaken in Chile.

Here, a Coho salmon farm observed the mortality in two groups of fishes naturally infected with Piscirickettsia salmonis over a period of 36 days. One dietary group contained 1.5% KDF. After the monitoring period the mortality in the fish fed with potassium diformate was significantly reduced from 40% to 33%.

Conclusion and outlook Though there are only a limited number of published studies available on the use of potassium diformate (Aquaform®) for growth promotion, anti-bacterial impact, feed efficiency, mineral absorption and pellet stability in salmonid aquaculture, results from those studies as well as widespread unpublished information on its commercial use in such diets from Europe, Asia and Latin America indicate promising potential and compel aqua feed manufacturers to consider using acidifiers, especially diformates in their Salmonid diets.

*FPI: Fish-Productivity-Index = Weight gain [g] x Survival [%] / (10 × FCR)

Aquaculture Scoop October 2015

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More information:

Nucleotides

K. Hoffmann (CHEMOFORMA AG) Email: info@chemoforma.com Web: www.chemoforma.com

Nucleotides – essential nutrients for successful aquaculture The need to better understand metabolism and nutrition in aquatic animals is driven by the increasing demand for high quality aquaculture products at an affordable price and satisfying the customer’s right for residue-free and flawless food. Financial losses due to diseases still strike producers severely everywhere in the world. Often the reasons for the outbreak of diseases are not obvious but increased mortalities or reduced meat quality are at least in part triggered by stressful husbandry, overstocking, poorly adjusted feed levels or inferior feed, as well as unsatisfactory water conditions or malnutrition.

Lots of discussions have been launched on options to maximise performance of animals while simultaneously minimising the use of therapeutic chemicals compromising the environment or supporting drug resistance.

An increasing number of products claiming to enhance health by supporting and enhancing immunity have appeared on the market.

Probiotics, prebiotics and synbiotics have been extensively studied in terrestrial animals and the number of reports from aquaculture is steadily increasing. The trend of both nutritionists and suppliers of additives to combine specific functionalities with food or feed is comprehensible and reasonable. The target still must be improving feed in terms of nutritional aspects, prevention of diseases and thereby profitable animal husbandry.

Aquaculture Scoop October 2015

Essential nutrients are nutrients that are required for normal body functions but cannot be synthesized in a given organism. For most essential nutrients such as vitamins, minerals, fatty acids or amino acids a ranking in terms of nutritional importance was already compiled for different animal species.

All essential nutrients must be available in the feed in a specific form and concentration required by the organism.

A deficiency of one essential nutrient can not be restored by an excess of another and the nutritional bioavailability is vital for the effective utilisation in the organism.

A second class of nutrients is required from dietary sources when the internal supply can not be guaranteed. During specific circumstances similar characteristics already listed for

Fig. 1: Under normal conditions the supply of nucleotides is guaranteed through autogenous metabolic and catabolic processes. The “de-novo synthesis” of nucleotides, or the reuse of nucleotides from dead cells (so-called “salvage pathway”) and the nutritional available dietary nucleotides allow meeting even temporary peaks in the demand for nucleotides without losses in performance.

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Nucleotides

essential nutrients likewise apply for conditionally essential nutrients.

For years, nucleic acids and nucleotides were not considered for use in any dietary program. It was supposed that all organisms are able to supply sufficient amounts of nucleotides to meet their physiological demand anytime. However scientific research has discovered remarkable and measurable benefits from supplementing diets with RNA/nucleotides. Nucleotides have universally valid, essential physiological and biochemical functions including e.g. encoding and deciphering genetic information, mediating energy

Aquaculture Scoop October 2015

metabolism and cell signalling as well as serving as coenzymes, allosteric effectors and cellular agonists. Changes in their concentrations and availability to cells may have very profound multifaceted effects on metabolism.

Various trials demonstrated that RNA/nucleotides not only improve general health of organism but also trigger performance.

For healthy organisms this constant re-supply of nucleotides is very well balanced and appropriately adjusted for response to occasional stress. Any increased demand for nucleotides takes time and energy and stresses the body’s supply of basic raw materials. During

times of extraordinary stress, such as rapid growth, reproduction, environmental change, combating disease and recovery from injury, substantial amounts of additional nucleotides must be readily available for cell multiplication.

The supply of nucleotides is controlled and maintained by the use of three metabolic or catabolic processes (Fig. 1).

The limited recycling of nucleotides from dead cells in adult organisms is called “Salvage Pathway”. This includes various biochemical and metabolic steps to release the nucleotides. The “de-novo synthesis” of nucleotides is a rather

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Nucleotides

complicated biochemical process including 10-14 different biochemical steps. Raw materials for the synthesis of nucleotides are, amongst others, amino acids. The synthesis requires energy which needs to be supplied by other metabolic processes in the organism.

Last but not least nucleotides may be extracted from the diet as all cellular feed ingredients contain nucleotides in form of DNA present in the nucleus of every cell. This process however is by far the most inefficient one as the DNA is protected from degradation by a specific class of proteins, the so-called Histone proteins. These proteins cover and shield the DNA and prevent it from disintegration and degradation.

Nevertheless these three pathways are sufficient to prevent a depletion of the internal nucleotide pool of the organism under normal conditions.

Nowadays various stressors (management, environment, transport) are present under intense farming conditions. Stress turns out to be permanent and continually poses a threat to health. Stress decreases the replication of special and crucial white blood cells and therefore negatively interferes with the bodyâ&#x20AC;&#x2122;s natural immune defence. Under times of high demand, the accelerated need for nucleotides has to be met either by internal synthesis or salvage, which are insufficient in most cases or from external sources such as the diet (Fig. 2).

Health challenges or stress typically impair on performance or development as the nucleotide pool is depleted and may not be refilled adequately leading to retardations in performance or recovery. One approach is to externally supply nucleotides (Fig. 3). This is of utmost importance for e.g. cells of the immune system, gastrointestinal cells or blood cells as these cells are only partially capable of producing nucleotides or lack the potential to synthesize them at all.

Aquaculture Scoop October 2015

Fig. 2: Under detrimental conditions universal in modern aquaculture, the supply of nucleotides cannot be guaranteed by internal resources. An effective reaction to health challenges or regenerative activities can only be guaranteed at the expense of performance as there are not enough nucleotides available for growth, reproduction or development.

The addition of nucleotides to the diet helps to refill the internal nucleotide pool thereby supporting processes dependent on unhindered multiplication of cells.

The benefits of RNA/nucleotide supplemented feed on performance and general health as well as development of young animals was tested in numerous trials in agriculture and aquaculture.

The following list of publications reflects some remarkable trials showing the positive effects of RNA/nucleotide supplemented feed aligned with the effects observed.

Disease resistance Burrells, C., Williams, P.D. & Forno, P.F. (2001) Dietary nucleotides: a novel supplement in fish feeds. 1. Effects on

resistance to disease in salmonids.

Aquaculture 199, 159-169.

Stress resistance Burrells, C., Williams, P.D., Southgate, P.J. & Wadsworth, S.L. (2001) Dietary nucleotides: a novel supplement in fish feeds.2. Effects on vaccination, salt water transfer, growth rate and physiology of Atlantic salmon.

Aquaculture 199, 171 â&#x20AC;&#x201C; 184.

Leonardi, M., Sandino, A.M. & Klampau, A. (2003) Effect of a nucleotide enriched diet on the immune system, plasma cortisol levels and resistance to Infectious Pancreatic Necrosis (IPN) in juvenile rainbow trout (Oncorhynchus mykiss). Bulletin of the European Association of Fish Pathologists 23(2), 51

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Nucleotides

Other References Metabolic cost to animal of purine synthesis Sanderson, I.R. and He, Y. (1994) Nucleotide uptake and metabolism by intestinal epithelial cells. Journal of Nutrition 124, 131S – 137S Use of salvage or synthesis nucleotide pathways in different tissues (López-Navarro, A.T., Gil, A. and Sánchez-Pozo, A. (1995) Deprivation of dietary nucleotides results in a transient decrease in acid soluble nucleotides and RNA concentration in rat liver. Journal of Nutrition125, 2090 – 2095.

Fig. 3: Supplementing feed with adequate amounts of high-quality nucleotides replenishes the internal pool and thereby supports performance even under adverse conditions. Dietary nucleotides are a management tool to maintain general health, enhance performance and manage the harmful effects of stress.

Salobir, J., Rezar, V., Pajk, T. & Levart, A. (2005). Effect of nucleotide supplementation on lymphocyte DNA damage induced by dietary stress in pigs.

Animal Science 81, 135-140.

Vaccines - enhancement of vaccine performance Ramadan, A., Afifi, N. A., Moustafa, M.M. & Samy, A.M. (1994) The effect of Ascogen on the immune response of Tilapia fish to Aeromonas hydrophila vaccine. Fish & Shellfish Immunology 4(3), 159-166 Burrells, C., Williams, P.D., Southgate, P.J. & Wadsworth, S.L. (2001) Dietary nucleotides: a novel supplement in fish feeds. 2. Effects on vaccination, salt water transfer, growth rate and physiology of Atlantic salmon. Aquaculture 199, 171 – 184.

Aquaculture Scoop October 2015

Differences between nucleotides and immunopotentiators Smith, V.J., Brown, J.H. & Hauton. (2003) Immunostimulation in crustaceans: does it really protect against infection? Fish & Shellfish Immunology 15 (1), 71 – 90.

Inability of lymphocytes to manufacture purines efficiently Saviano, D.A. and Clifford, A.J. (1978) Absorption, tissue incorporation and excretion of free purine bases in the rat.

Nutritional Reports International 17, 551 – 556.

Effects of Nucleotides on the Immune Systems Li, P. & Gatlin, D.M. (2006) Nucleotide nutrition in fish: Current knowledge and future applications. Aquaculture 251( 2-4), 141-152

Protection against Staphylococcus aureus Kulkarni, A.D., Fanslow, W.C., Rudolph, F.B., Van Buren, C.T., (1986). Effect of dietary nucleotides on response to bacterial infections. Journal of Parenteral & Enteral Nutrition 10, 169–171.

Protection against Candida albicans Carver, J.D., (1994). Dietary nucleotides: cellular immune, intestinal and hepatic system effects. Journal of Nutrition 124 Supplement 1S, 144S–148S. Protection against Streptococcus iniae Li, P., Lewis, D.H., Gatlin, D.M. (2004) Dietary oligonucleotide from yeast RNA influences immune responses and resistance of hybrid striped bass (Morone chrysops X Morone saxatilis) to Streptococcus iniae infection. Fish & Shellfish Immunology 16, 561 – 569.

Protection against Aeromonas hydrophila (Use of clearance from blood as protection indicator) Sakai , M., Taniguchi, K., Mamoto, K., Ogawa, H. And Tabata, M. (2001) Immunostimulant effects of nucleotide isolated from yeast RNA on carp, Cyprinus carpio. Journal of Fish Diseases 24, 433 – 438.

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More information:

Best practice

Stephen G. Newman Ph.D. President and CEO AquaInTech Inc. USA Web: www.aqua-in-tech.com

Aquaculture is agriculture in water based ecosystems Global production of protein from aquaculture has increased between 5 and 10% per year for the last few decades with no immediate end in sight. There are many reasons for this although some would argue that this growth is occurring in spite of how things are being done and that it is far from sustainable. A number of NGOs have appointed themselves as experts and there are a number of programs that claim, if they are followed, to lead to true sustainability. Much as the term organic is bandied about as if it actually means something (it has a legal definition although nothing that is even remotely universally agreed upon) it is indeed unfortunate that the term “sustainable aquaculture” remains largely an oxymoron.

A compelling argument could be made that given the extreme diversity of production systems, incremental progress is important and perhaps all that can be expected. However it seems that the vast majority of these self-anointed groups of experts have specific areas that they focus on often missing the big picture. Critical elements are ignored in favor of focusing on social, cultural and environmental issues and not what actually constitutes sustainability in the field. Too little to no emphasis is placed on the pivotal role of animal health and the need for science based proactive animal health strategies.

The current system favors a medieval approach to the movement of animals and thus pathogens between and throughout the global aquaculture production system.

of US dollars and there is no doubt that shrimp farming has enriched the lives of many. It is indeed unfortunate that there are far more farmers who have little understanding of the science of aquaculture, an absolutely essential element of true sustainability, than do.

Farming shrimp is not the same as growing rice. In many areas of SE Asia, far too many rice farmers are growing shrimp simply because it pays better when it succeeds. While it can be relatively easy this rarely persists beyond the first few cycles. Aquatic environments are constantly changing in response to inputs.

Most farmers are ill prepared educationally and economically to deal with this.

Perhaps the single largest barrier to true sustainability (which I define simply as the sum of cultural practices that ensure that environmental impacts are negligible-this can encompass a wide range of issues- and

that control the impact of diseases ensuring that farmers can produce consistently cycle after cycle) is ignorance.

This is fueled by a multitude of companies and individuals many of whom are self-styled experts knowing little about aquaculture, peddling adulterated “magic bullets” to unwitting farmers.

Diseases are an inherent part of all agricultural processes. Terrestrial monoculture agriculture relies on chemicals, pesticides and other tools to combat the propensity for disease. These are not as readily applicable to water based production systems. Production in aquatic ecosystems has the added element of water and a multitude of chemical processes that do not occur in land based systems. Failure to consider how diseases gain entry into production systems, how they are spread and failure to adapt to the altered conditions

Aquaculture practices that are not geared towards sustainability pose a major challenge to aquaculturists everywhere.

Shrimp exports are a very valuable source

Aquaculture Scoop October 2015

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Best practice

of culture that they might impose is the norm for many paradigms. In my opinion, for any segment of the aquaculture industry to be considered truly sustainable, they must address these critical elements.

Perhaps one of the most recent examples is that of a wide spread disease (apparently a toxicosis) that is still spreading and has had huge negative financial consequences on the global farmed shrimp industry. The disease, initially coined Early Mortality Syndrome (EMS), largely because early observations of the disease occurred within the first 30 days of stocking, and subsequently renamed Acute Hepatopancreatic Necrosis Syndrome or Disease (AHPNS or AHPND) has been determined to be the result of the presence of a strain of Vibrio parahaemolyticus. This strain carries genes that encode for a bivalent protein toxin that targets the hepatopancreas specifically damaging it with resultant impacts on the shrimp ranging from high levels of acute mortality to sluggish growth and poor overall productivity.

The first published reports demonstrated that this bacterium was transmitted via infected adults to PLs that succumbed shortly post stocking.

We now know much more about this disease process. The pathogen moves through the environment and this very rapidly growing bacterial strain favors accumulated organic matter and detritus. Notably, in some areas of the world a change in the production paradigm has successfully mitigated the The steps that need to be taken fall into general categories and in the case of EMS quite a few specifics. There are things that can be done to minimize the chances of this happening. They start with a better understanding of some fundamentals. If you are operating a hatchery/maturation facility with no microscope, no ability to do basic

Aquaculture Scoop October 2015

problem. It looks very much like the presence of the bacteria responsible for EMS can be impacted in a number of ways. However complacency is unwise as it is probable that something else will come along that thrives on some elements of these eco-manipulated pond ecologies and kills shrimp. Efforts must be taken to permanently break some elements of this cycle.

microbiology and water chemistries, then you clearly have not gotten the message. Proper use of the tools of science is the only path to sustainable production. This list is not all inclusive but consider these highlights as described.

The steps that need to be taken fall into general categories and in the case of EMS quite a few specifics. There are things that can be done to minimize the chances of this happening. They start with a better understanding of some fundamentals. If you are operating a hatchery/maturation facility with no microscope, no ability to do basic

should be regulated and only those producing animals under biosecure conditions with appropriate histories, operational SOPs, etc. should be allowed to sell adult animals. This includes tracking animals performance in the field to ensure that the problems that do occur did not originate in the broodstock. The use of wild broodstock should be illegal.

1. There should be no unrestricted movement of broodstock. Producers

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2. The use of pond reared broodstock that are held in non-biosecure environments should be strictly forbidden and heavily enforced. PCR screening of animals on a population basis is not a suitable barrier. In fact it is all too often represented as being such and has done massive amounts of harm to farmers.

3. Pathogens can appear suddenly and evolve very quickly given the right conditions. “New” pathogens can easily slip through many different barriers, much as has happened with the microsporidian that causes EHP. Vigilance and consistent use of science based tools is critical for proactive disease management.

4. Hatcheries need to be “regulated” as well. Archaic outdoor culture of Artemia and algae ensures high levels of bacteria are present, often vibrios species (the major source of problems for farmed shrimp). These bacteria are cultured in production systems and the PLs carry these potential pathogens into the production systems (as is believed to be the case with EMS). A microscope and some tools for counting bacteria are critical tools.

5. Standards need to be enforced for acceptable quality and survival during production. Low survival tanks should be destroyed and not pooled. They died for a reason even if the cause is not readily apparent to the hatchery staff.

7. Biosecurity needs to be a routine part of production processes and enforced. It makes no sense to go through the many steps needed to ensure that animals are truly free of specific pathogens only to undo it by ignoring protocols when PLs are harvested and packaged for delivery to farms.

8. Certification by audit while it could eventually be a useful component of this needs to evolve and deal with culture realities. Failure to ensure science based production is not consistent with sustainability.

9. Stocking of PLs on farms needs to be coordinated in a manner that ensures that the PLs are not overly stressed during transport and immediately post-stocking.

10. Reasonable limits need to be set on farm numbers, size and geographical distribution. These need to be enforceable.

Farms should not be on top of each other.

11. Outdoor production systems are biosecurity risks. This is inherent in their nature.

12. Proper pond design and preparation are essential. Organic matter should not be present at the start of the cycle and every effort made to ensure it does not accumulate. Responsible removal to ensure no environmental impact is important.

13. Stress reduction at all levels of the production process by the proper use of aeration, not over fertilizing, use of water exchange (depends on production system), proper nutrition, etc. is essential for the ability of shrimp to realize their genetic potential.

14. Use lower protein feeds. In most cases feed companies Penaeus vannamei are being fed protein levels that are much higher than the shrimp need.

15. There is good field data that suggests that the impact of EMS can be lessened or even largely negated by the use of small ponds, co-cultivation with Tilapia, modest water exchange rates, better feed management and effective management to prevent the accumulation of organic material.

Clearly it is not possible to detail all of the steps that need to be taken in a short article. While books have been written about this subject following the above guidelines and moving towards a science based production paradigm where proactive disease management is a significant feature can positively impact the bottom line. Without this there is little hope that regardless of the certification schemes that the farms are aligned with that they will truly be sustainable.

6. The proper use of certain products (such as our PRO4000X) in the hatchery tanks along with the use of certain chemicals-not antibiotics-but disinfectants that break down rapidly in the environment should be routine when other measures fail to control potential pathogen loads. There are far too many products in the market place of questionable usefulness and many that are useless.

Aquaculture Scoop October 2015

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Expo List

Events in detail October 6th International Exhibition of Fishing and Aquaculture (SIPA '2015) 1st-4th October Algeria www.algeriasipa.com 9th International Abalone Symposium 5-10th October Korea www.ias2015.co.kr Conxemar 5-7th October Vigo, Spain www.conxemar.com/v_portal/apartados/ apartado.asp?te=342 DanFish International 2015 7-9th October Aalborg, Denmark http://uk.danfish.com/danfish/uk.aspx DanAqua 7-9th October Aalborg, Denmark http://uk.danaqua.net Aqua Fair Asia 8-11th October Shanghai, China www.petfairasia.com/en/featured/aquarium Aqua Fisheries Myanmar 2014 14-16th October Yangon, Myanmar www.myanmar-aquafisheries.com Aqua 2015 19-22nd October Guayaquil, Ecuador www.cna-ecuador.com/aquaexpo Aquaculture Europe 2015 20-23rd October Rotterdam, Netherlands www.marevent.com Seafood Directions 2015 25-27th October Perth, Australia www.seafooddirections.net.au

Aquaculture Scoop October 2015

GOAL (Global Outlook on Aquaculture Leadership) conference 26-29th October Vancouver, Canada www.gaalliance.org/GOAL2015/index.php

4th Annual World Congress of Ocean 2015 6-8th November Qingdao, China http://www.bitcongress.com/wcaf2015

Seafex 27-29th October Dubai, UAE www.seafexme.com

Latin American & Caribbean Aquaculture 2015 16-19th November Fortalza Brazil www.marevent.com/LAA2015_BRAZIL

International Conference of Aquaculture Indonesia 2015 29-31st October Jakarta, Indonesia http://icai.aquaculture-mai.org International Conference on Agriculture, Aquaculture Fisheries and Animal Science (ICAAFAS2015) 30-31st October Cebu, Philippine www.icaafas2015.weebly.com Busan International Seafood & Fisheries EXPO 2015 29-31st October Busan Korea www.bisfe.com/eng/bisfe/outline.php November China Fisheries & Seafood Expo 4-6th November Aoshan Bay, China www.chinaseafoodexpo.com/ Expo Pesca AcuiPeru 5-7th November Lima, Peru www.thaiscorp.com/expopesca/ 4th Annual World Congress of Aquaculture and Fisheries 2015 6-8th November Qingdao, China http://www.bitcongress.com/wcaf2015/ 5th Annual World Congress of Marine Biotechnology 2015 6-8th November Qingdao, China http://www.bitcongress.com/wcbm2015/

Marel Seafood ShowHow 18-20th November Seattle, USA www.marel.com/fishprocessing/events/seafood-showhow-seattle/3038 Agra Innovate 24-26th November Lagos, Nigeria www.agra-innovate.com December Agra Innovate 8-10th December Nairobi, Kenya www.agra-innovate.com International Shrimp Symposium (ISS) 14-16th December Bushehr, Iran www.iss2015.ir January 2016 20th Edition India International Seafood Show 22-24th January Chennai, India www.indianseafoodexpo.com MVC Cereals-Mixed Feed Veterinary 2016 26-28 January Moscow Russia www.mvc-expohleb.ru

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