2006 marked a turning point in European aquaculture, when the European Union ratified a ban on the non-medical use of antibiotics in the regulation on feed additives for use in animal nutrition (EC № 1831/2003).

1. May | June 2011
Feature title: Preliminary effects of β-glucans on Nile tilapia health and growth performance
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2. F: β-glucans F:F: β-glucans
Microalgae
Table 2: Cyanobacteria as a potential source of
fermentable carbohydrates Experimental design
(Vargas et al. 1998, J. Phycol. 34, 812) required to achieve this The experiment was under-
Carbohydrates ambitious goal, but also taken at the Aquaculture and Fish
the combination of this Nutrition Research Aquarium,
Preliminary effects of
Strain (% of dry
weight) process with a realistic University of Plymouth, UK. Nile
β-glucans on Nile tilapia
Strategic and Business tilapia (Oreochromis niloticus) (6.8
Plan. ± 0.2g) were randomly distributed
Anabaena sp. ATCC 33047 28.0 ± 2.0 1
into 12 1: AlgaEnergy’s CO2BIOCAP
Figure x 150-l fibreglass tanks
Anabaena variabilis 22.3 ± 2.5 R&D and containing well-aerated recirculated
mobile laboratory
Anabaenopsis sp.
Figure 1: Growth performance
16.3 ± 1.5 a realistic
Figure 2: Total circulatory freshwater. Fish were fed to appar-
of Nile tilapia after 10 weeks 16.9 ± 2.6
Nodularia sp. (Chucula) Business Plan
leukocyte levels of fish ent satiation 3 times a day for 70
health and growth performance of feeding on experimental 37.6 ± 2.5
Nostoc commune
diets. Data expressed as means
Nostoc paludosum
± Standard deviations 26.6 ± 1.9
after 70 days of is developing a
AlgaEnergy feeding on
experimental diets
responsible scientific agenda
aimed at achieving the commer-
kind, days. Fish incorporate four types on
which will were batch weighed of
photobioreactors (PBR): columns, tubular
a weekly basis following a 24 hr
reactors, semi-open and and reared at 28
starvation period in a second stage,
Nostoc sp. (Albufera) 26.8 ± 4.0 cially viable production of biofuels raceways. Thewith a will be entirely auto-
± 1ºC plant 12:12 hr light:dark
The use Nostoc sp. (Caquena) diets for ± 1.7
of glucans in practical 23.3 However, there is from data regarding The
derived little microalgae. the mated and controlled by specially designed
photoperiod.
fish such as turbot (Scophthalmus maximus, ± 2.0
Nostoc sp. (Chile) 23.3
immune response and growthprovided for
R&D programmes performance software, which manages all38% crude pro-
Two isonitrogenous (ca. the cultivation
by M D Rawling and H Kühlwein, Aquaculture Nutrition and Health Research Group, School of Biomedical and Debaulney et al., 1996), rainbow trout of tilapia that purpose apparentthe selection
when fed to include satiation on parameters. Its goal(ca. 12%research lipid)
tein) and isolipidic is to crude and
Biological Sciences, University of Plymouth, UK Nostoc sp. (Chucula) 15.7 ± 1.8
(Oncorhynchus mykiss, Peddie et al., 2002), diets containing β-glucans (Whittington on
and genetic engineering work et develop new PBR processes and The basal
diets were formulated (Table 2). technolo-
Atlantic salmonNostoc sp. (Llaita)
(Salmo salar, Salinas et al., ± 1.5 2005).various types of microalgae, which
20.2
2
al., gies in this field. For this reason, the plant
diet served as a control diet (diet A).
006 marked a turning β-(1,6)-linked D-glucopyranosyl side chains, Immunomodulatory sea sp. (Dicentrarchus ± 1.2 Consequently, the aim of the of lipids
2004), EuropeanNostoc bass(Loa) 32.1 carry substantial quantities current will have the flexibility and capacitythe grow
Experimental diet B consisted of to basal
point in European aquac- in which case it provides a comb-like mechanisms of action of labrax, Bagni et al., 2005) is well documented. investigationcarbohydrates (some of which
or was to assess dietary inclu- diet supplemented with β- glucan micro-
simultaneously different species of at 310
ulture, when the European structure (Bohn and BeMiller, 1995). β-(1,3)(1,6)-D-glucans and for transport), and the flue gases from sion of a commercial
are patented), the development of mg kg1 different growing conditions, using
algae in diet. The glucan source was a blend
Union ratified a ban on the The most abundant source of natural Pathogens exhibit evolutionary con- conventional energy generation facilities β-glucan on the growth
new photobioreactors more efficient and of β-(1,3) outdoor PBR. The cultivation
indoor andand (1,6) chained glucan. Each
non-medical use of antibiotics in β-glucans with highly immunomodulat- served pathogen-associated molecular canTable 2: Formulation of experimental diets.of
therefore be used as a 1source Each ingredient costs, performance, feed utilisa-
with lower and the establishment of area was be initially by mechanically m2 and
diet will produced of about 1,000 stirring
component is expressed as g kg per diet
the regulation on feed additives ing properties are yeasts, where research patterns (PAMPs), which are recognised CO2 for large-scale microalgae cultivation tion, and innate immune
a suitable and scalable production process. the ingredients into uphomogenous mixture
culture volume a to 72,000 l.
for use in animal nutrition (EC № effort has focused in particular on β-(1,3) by host immune cells via contact with spe- installations. DietsAt present, biofuels produced tilapia
response of Nile from using a Hobart food mixer.be visited during
AlgaEnergy’s plant will
1831/2003). (1,6)-D-glucans, extracted from the baker’s cific receptors such as pattern recognition Ingredients
The production of liquid biofuels for A B (Oreochromis competitive
microalgae are not financially niloticus). theWarm water wasEurope congress that
3rd Algae World added to reach a
yeast Saccharomyces cerevisiae. The β-glucan receptors (PRRs) (Medzhitov and Janeway, vehicles (biodiesel and bioethanol), is a very with the first-
This put a statutory stop to the use layer in the middle of the three-layered 2000; Didierlaurent et al., 2005). promising alternative
Herring meal LT921 300.00 generation bio-
300.00
of all antibiotics and ionophore anticoc- yeast cell wall gives strength and rigid- It is recognised that PRRs for β-glucans A series of factors must be taken into
2
fuels obtained 18th Annual Practical Short Course on
Corn starch 365.01 365.01
cidials as growth promoters in intensive ity to the cell wall, forming a microfibrillar are present in all vertebrates as well as account when selecting microalgae as a from conven-
aquaculture practice and alternatives network. invertebrates (Raa, 2000) and in addition Lysamine pea protein3 164.74
source of biofuel precursors, such as: high 164.74
tional agricultur-
Aquaculture Feed Extrusion,
have received much attention (Bricknell There are other β-(1,3)-glucans from are important for the recognition of fungal 3
productivity, temperature tolerance,100.00
Glutalys (maize) toler- 100.00
al crops, and bio- Nutrition, & Feed Management
and Dalmo, 2005; Merrifield et al., 2010; different sources available (Table 1). One pathogens. As a result it has been well docu- ance tooil4 high performance in fermenta-
Fish pH, 30.00 mass30.00
production September 25-30, 2011
Dimitroglou et al., 2011). of the first studies conducted in 1969 mented that β-glucans have positive effects ble Soybean oil
carbohydrates for ethanol production 17.75 and 17.75
processing
Such measures may help to facili- by Chihara et al., showed an inhibit- on the immune cells of both fish and shrimp. or in fatty acids transformable to biodiesel, must therefore o 30+ lectures over a wide
PNP Vitamin premix5 20.00 20.00
tate consumer perceptions of bio- ing effect of the fungal β-glucan len- Indeed it has been reported that β-glucans for example. be substantially variety of aquaculture
Barox plus liquid (antioxidant) 0.500 0.500 industry topics
security and eco-friendly fish farming. tinan on tumour growth in transplanted increase the activity of phagocytic cells (for We also need to establish the most improved so that
In this context much attention has been mice tumours after systemic infection. example, macrophages) and the production β-glucan6
suitable type of cultivation system to -be 1.00
the price of the o one-on-one interaction with
focused towards the development of Lentinan and schizophyllan are nowadays of signal molecules such as cytokines, which used (open, closed or mixed), and the most product can be qualified industry experts
immunomodulatory compounds such as used clinically in cancer therapy in Japan results in the generation of new immune favourable operating conditionsbasis)
Proximate analysis (% dry matter
(batch, reduced by an Dry Extruder
o at the internationally
β-glucans. (Kaneko et al., 1989). cells (Raa, 2000). semi-continuous, continuous, number of order of magni- recognized Food Protein R&D Center on the campus
phases, matter (%)
Dry etc.). 93.7 tude94.2
at least. of Texas A&M University in College Station, Texas
Sources and Table 1: Overview of other available beta (1,3)-D-glucan sources (adapted from Soltanian et al, 2009) Tables Protein 3 below show some exam-
Crude 2 and (%) 37.8 A39.3 n e r g y
lgaE
chemical o discussion and live equipment
Origin β-glucan Branching frequency Reference ples of cyanobacteria as potential sources
Crude lipid (%) 8.6
is currently
8.6
structure of fermentable carbohydrates for ethanol engaged in the demonstrations following lectures
Ash (%) 6.9 6.8 on four major types of extruders
β-glucans are widely production and the lipid content of some construction of
Lentinus edodus (Shiitake) Lentinan 2/5 Wenner et al., 2008 -1)
o various shaping dies (sinking,
distributed in nature microalgae for biodiesel production. 20.4
Gross energy (MJ kg 19.5
its first plant, a
and can be found in the Sclerotium glucanicum & sclerotiorum Scleroglucan, SSG 1/3, highly branched Rice et al., 2005 raised by B = β-glucan Te
The expectations control diet, microalgae diet. c h n o l o g i c a l
Dietary codes: A = floating, high fat), coating (surface
cell walls of yeasts, cere- Fungi Schizophyllum commune Schizophyllan 1/3 Kubala et al., 2003 as 1 Fish meal: of second-generation bio- Scotland, UK. for
a source United fish products, Aberdeen, Platform vs vacuum), nutrition, feed
al grains, algae, bacteria, fuels have led to the creation of a large Experimentation formulation, and MUCH MORE!
Grifola frondosa (Maitake) Grifolan 1/3 Tada et al., 2009 2 Corn starch: Sigma Aldrich Ltd, UK.
fungi and mushrooms. number of companies, some of which have with Microalgae Twin Screw Extruder
Poria cocos Wolf Pachyman 1.0-1.3 Wang et al., 2004 3 significant investment. Our Frêres, France. P T E M ) ,
β-glucans belong to madeLysamine pea protein: Roquette company (
the group of polysac- Laminaria digitata Laminarin 1/10 Osmond et al., 2001 AlgaEnergy isSevenseas Ltd, UK. in the near
4 Epanoil: convinced that located at the For more information, visit
Seaweed
charides consisting of Laminaria hyperborea Laminaran 0.05 Nagaoka et al., 2000 future microalgae will be able to provide International
5 Vitamin premix: each 1kg of premix contains: 12.1% http://foodprotein.tamu.edu/extrusion
repeating β-(1,3)-linked us with these forms of Vit A 1.000 µg/kg, Vit D3 0.100
calcium, Ash 78.7%,
clean energy so Airport of or contact
Euglena gracilis Paramylon - Skjermo et al., 2006
D-glucose monomers Algae µg/kg, Vit (as Madrid-Barajas.
necessary for Ethe alpha tocopherol acetate) 7000.0 mg/kg,
sustainable economic Dr. Mian N. Riaz
that can be linear or Chaetoceros mülleri Chrysolaminaran 0.005-0.009 Bäumer et al., 2001 development(as cupricsocieties. Not only mg/kg,This is intended
Copper of our sulphate) 250.000 is Magnesium mnriaz@tamu.edu
branched with ran- Bacteria Alcaligenes faecalis Curdlan unbranched Kataoka et al., 2002 constant research and 0.52%
1.56%, Phosphorus development the to be a model 979-845-2774
Full Fat Soy Demonstration
domly distributed single Lichen Umbilicaris pustulata Pustulan unbranched Yiannikouris et al., 2004 basisβ-glucan: a blend of innovation (1,6) chainedplatform of its
6 for a continuous β-(1,3) and process glucan.
20 | InternatIonal AquAFeed | May-June 2011
24 May-June 2011 | InternatIonal AquAFeed | 21
25

3. F: β-glucans F: β-glucans
Bricknell, I. and Dalmo, R.A.: Fish & Shellfish 22 September 2003 on additives for use in animal Experimental Therapeutics, 314: pp. 1079-1086.
consistency suitable for cold extrusion to twice per day, as opposed to three times (Thompson et al., 1995) and Asian cat- Immunology, 2005. 19: pp. 457-472. nutrition, 2003.
form 1 mm pellets. per day in the present study. Efthimiou fish (Clarias batrachus; Kumari and Sahoo, Robertsen, B. et al., in: Stolen J. and Fletcher T.C.,
Chihara, G. et al. Nature, 1969. 222: pp. 687-688. Kaneko, Y. et al. International Journal of Editors, Modulators of Fish Immune Responses,
(1996) reported no improvements of den- 2006a). Contrary to these investigations,
Immunotherapy, 1989. 5: pp. 203-213. SOS, Fair Haven, 1994. pp. 83-99.
Results and discussion tex (Dentex dentex) growth performance the result of the present study showed Cook, M.T. et al. Fish & Shellfish Immunology, 2003.
when diets were supplemented with 0.5% that after 70 days of feeding fish on diets 14: pp. 333-345. Kataoka, K. et al. Journal of Biological Chemistry, Salinas, I. et al. Fish & Shellfish Immunology, 2004.
Growth, feed utilisation β-(1,3) (1,6)-D-glucans every second week containing β-glucan had no observable Couso, N. et al. Aquaculture, 2003. 219: pp.
2002. 277: pp. 36825-36831. 17: pp. 159-170.
and carcass analysis for two months. effect on serum lysozyme activity (567.1U. 99-109. Kubala, L. et al. Carbohydrate Research, 2003. 338: Selvaraj, V. et al. Fish & Shellfish Immunology, 2005.
This study endeavoured to determine However, similar to the present study ml-1, P > 0.05) when compared to control pp. 2835-2840. 19: pp. 293-306.
Dalmo, R.A. and Bogwald, J.: Fish & Shellfish
the growth performance and health effects dietary β-glucans have been reported to fed fish (693.8U. ml-1). Kumari, J. and Sahoo, P.K.: Diseases of Aquatic
Immunology, 2008. 25: pp. 384-396. Skjermo, J. et al. Aquaculture, 2006. 261: pp. 1088-
of including β-glucan in diets for Nile improve fish growth performance, where Despite not being significantly different Organisms, 2006.70: pp. 63-70. 1101.
tilapia. Growth performance and feed Cook et al. (2003) fed a commercial the activity was considerably less than the deBaulny, M.O. et al.: Diseases of Aquatic
Medzhitov, R. and Janeway, C. Jr.: Immunological
utilisation of tilapia after 10 weeks feed- β-glucan preparation to snapper (Pagrus control, which may be explained by the Organisms, 1996. 26: pp. 139-147.
Reviews, 2000. 173: pp. 89-97.
Soltanian, S. et al. Critical Reviews in Microbiology,
ing on experimental diets is presented auratus) at a dose of 0.1% of diet weight high dietary glucan supplementation; previ- 2009. 35: pp. 109-138.
Didierlaurent, A. et al.: Cellular and Molecular Life
Merrifield, D.L. et al. Aquaculture, 2010. 302: pp.
in Table 3 and Figure 1. A high growth for 84 days. ously, Whittington et al., (2005) found that Sciences, 2005. 62: pp. 1285-1287. Tada, R. et al. Carbohydrate Research, 2009. 344:
1-18.
performance was observed in both groups; In a similar investigation Misra et al. tilapia serum lysozyme activity significantly pp. 400- 404.
Dimitroglou, A. et al.: Fish and Shellfish
fish biomass increased by over 900% with (2006) fed a β-glucan extracted from barley decreased (P < 0.05) when fed dietary Misra, C.K. et al. Aquaculture, 2006. 255: pp. 82-94.
Immunology, 2011. 30: pp. 1-16. Thompson, K.D. et al. Diseases in Asian
feed conversion ratio (FCR) ≤ 1.0 and to rohu (Labeo rohita) fingerlings at a dose β-glucan at 200 mg kg-1. Similarly Anderson Nagaoka, H. et al. Hepatogastroenterolgy, 1999. aquaculture, 1995. 11: pp. 433–439. Fish Health
specific growth rate (SGR) > 3.5. SGR ranging from 0-500 mg β–glucan kg of diet (1992) and Couso et al. (2003) found nega- Duncan, P.L. and Klesius, P.H.: Journal of Aquatic
46: pp. 2662-2668. Section, Asian Fisheries Society, Manila, Philippines.
improved significantly from 3.5 ± 0.06% for 56 days. tive effects towards fish immune responses Animal Health, 1996. 8: pp. 241-248.
Osmond, R.I. et al. European Journal of Wang, Y. et al. Carbohydrate Research, 2004. 339:
in the control fed fish (group A) to 4.1 ± In the present study after 70 days of and disease resistance when fed dietary Efthimiou, S.: Journal of Applied Ichthyology-
Biochemistry, 2001. 268: pp. 4190-4199. pp. 2567-2574.
0.15% in the β-glucan fed fish (group B; feeding on the experimental diets feed β-glucan at 10 g kg-1 for periods of up to Zeitschrift für Angewandte Ichthyologie, 1996. 12:
P = 0.005). Mean final weight gain of the intake of fish fed β-glucan (36.6g kg-1 BW-1 40 days. pp. 1-7. Peddie, S. et al. Veterinary Immunology and Wenner, C. A. et al. Planta Medica, 2008. 74: pp.
β-glucan fed fish (72.1g fish-1, P = 0.004) day-1) was considerably higher (35.5 – 38.6g Compared to control fed fish (1.61 x 104 Immunopathology, 2002. 86: pp. 101-113. 909-910.
Engstad, R.E. et al. Fish & Shellfish Immunology,
was significantly greater than control fish kg-1 BW-1 day-1) than control fed fish (28.3g µl-1) total leukocyte levels were significantly 1992. 2: pp. 287-297. Raa, J.: In: Avances en Nutricion Acuicola V. Merida, Whittington, R. et al. Aquaculture, 2005. 248: pp.
(50.9 g fish-1). kg-1 BW-1 day-1); however, this was not elevated in fish fed β-glucan diets (3.53 x Yucatan, Mexico: Memorias del V Simposium 217-225.
significant due to high 104 µl-1, P < 0.001) (Figure 2). This result The European Parliament and the Council of the
Internacionale Nutricion Acuicola. 2000.
European Union: Regulation (EC) No 1831/2003 Yiannikouris, A. et al. Journal of Food Protection,
Table 3: Growth performance of Nile tilapia after 10 weeks variance. This trend is at is consistent with data reported for vari-
of the European Parliament and of the Council of Rice, P.J. et al. The Journal of Pharmacology and 2004. 67: pp. 2741-2746.
of feeding on experimental diets. Values expressed as means least suggestive toward ous fish species including: Atlantic salmon
and pooled standard error. Dietary codes: A = control diet, B = increased absolute mean (Robertsen et al., 1994), channel catfish
β-glucan diet feed intake of fish fed (Ictalurus punctatus; Duncan and Klesius,
Diets on β-glucan to satiation 1996), common carp (Cyprinus carpio;
three times a day; fur- Selvaraj et al., 2005) and rohu (Misra et
Parameters A B
ther research is required al., 2006). The data from the present study
to evaluate appetite suggests that the inclusion β-glucan at the
Initial body weight (g fish -1) 6.9 6.7 response and optimise dietary levels used had no detrimental
β-glucan concentration. effects towards the measured fish health
Final Body weight (g fish-1) 57.8a 78.8b
Despite increased growth parameters.
Weight gain (g fish-1) 50.9a 72.1b
compared to control fed
Food consumption (g kg-1 BW-1 day-1) 28.3 36.6 fish, the supplementation Conclusion
Condition factor (k) 1.82a 1.99a of β-glucan had no effect The present study demonstrated that
Net protein utilisation (NPU) 49.0 50.4 on feed utilisation and β-glucan fed to Nile tilapia at 310mg
Protein efficiency ratio (PER) 2.59 2.59 carcass analysis β-glucan kg-1 for 10 weeks had a positive
effect on growth with no apparent detri-
Specific growth rate (SGR) 3.5a 4.1b
Haematology mental effects towards carcass composition
Feed conversion ratio (FCR) 1.0 0.9 and immunology or health status. Although there was no
abSignificant differences between groups are indicated by
Biochemical and significant difference in the feed intake it
superscript letters haematological analysis was apparent that feed intake of fish fed
can often provide vital β-glucan was considerably improved. Feed
information for health utilisation was not significantly affected
Contrary to the findings of the present and management assessment of cultured further indicating that improved growth
study, an investigation by Whittington et al., fish. In the present study haematocrit, may have been due to improved appetite of
(2005) reported that a yeast β-glucan at haemoglobin and erthyrocyte levels were fish fed diets containing β-glucan.
dietary levels of 50, 100 & 200 mg β–glucan not affected by the inclusion of β-glucans
kg did not significantly affect weight gain of (data not shown). Serum lysozyme activity References
tilapia after 84 days of feeding. also remained unaffected. Research has
Anderson, D.P.: Annual Review of Fish Diseases,
The current study used a commercial demonstrated that β-glucans can enhance 1992. 2: pp. 281-307.
product at 310 mg β-glucan kg-1. The dif- the non-specific immune response of fish
ferences of growth performance may be (Dalmo and Bogwald, 2008). Indeed, yeast Bagni, M. et al. Fish & Shellfish Immunology, 2005.
18: pp. 311-325.
explained by the higher β-glucan level in the glucans have been reported to enhance
current study or the fact that Whittington lysozyme activity in Atlantic salmon Bäumer, D. et al. Journal of Phycology, 2001. 37:
et al., (2005) fed to apparent satiation only (Engstad et al., 1992), rainbow trout pp. 38-46.
22 | InternatIonal AquAFeed | May-June 2011 May-June 2011 | InternatIonal AquAFeed | 23

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