Brewers’ yeast as a supplement in aquaculture


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The effect of stress caused by environmental pollution and farming conditions on the health and yield of fish in intensive aquacultures is becoming increasingly important.

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Brewers’ yeast as a supplement in aquaculture

  1. 1. May | June 2012 Feature title: Brewers’ yeast as a supplement in aquaculture International Aquafeed is published five times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2012 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058The International magazine for the aquaculture feed industry
  2. 2. FEATUREBrewers’ yeastas a supplement in aquacultureby Jan Frericks, Leiber GmbH, GermanyT he effect of stress caused by envi- therapeutic antibiotics for fish. The transfer of nutrients accumulate within the cells of the ronmental pollution and farming genes for resistance between different spe- yeast species Saccharomyces cerevisiae. Being conditions on the health and yield cies of bacteria is accelerated, leading to an organically bound ensures high availability of fish in intensive aquacultures is exacerbation of the problem of resistance in of these active substances. Dried brewers’becoming increasingly important. the treatment of human diseases worldwide. yeast is used very often in fish nutrition due Future-oriented production methods in to the high bioavailability of the constituent Factors such as stocking density, con- the fish farming industry should therefore compounds.tamination, toxins, pollutants and outbreaks of be targeted towards minimising the use of In addition to this, brewers’ yeast hasdisease have a negative effect on the immune antibiotics and medicinal drugs. It is of great cell walls that are composed of mannan-status of the fish. The consequence of this is importance to analyse the negative effects oligosaccharides (MOS). This complex net-an increased susceptibility to infection through caused by environmental pollution and farm- work of mannans and ßglucans serves as abacterial, viral, fungal or parasitic pathogens. ing methods. substrate for the beneficial gut flora. TheIncreased loss rates and reduced growth More crucial still will be to influence the fishs limited digestive tract benefits inperformance result in lower profitability for animals metabolism so that external toxins particular from the prebiotic properties ofthe fish production industry. have a lesser impact, even under intensive the yeast cell walls, which stabilise the gut As a consequence, the monetary and conditions. A healthy gut and a functioning and ensure a healthy balance of microflora "The cell wall of brewers’ yeast comprises approximately 20-25% mannans and 25-30% ß-glucans. ß1,3/1,6(D) glucan molecules can be isolated from it using special hydrolytic processes. The molecules consist of characteristic (1,3)-beta-glycosidic linked D-glucose subunits connected with with irregular beta-(1,6)-linked side chains of various length. Only this free ß-glucan structure from Saccharomyces cerevisiae has an immunomodulatory effect on the metabolism"quantitative overheads for the vaccination non-specific immune response are fundamen- (eubiosis). In addition to this, the mannan-and medicinal treatment of the fish increases. tal prerequisites for this. oligosaccharides in brewers’ yeast are ableIn many cases, antibiotics are given not only to bind harmful toxins in the food, andtherapeutically, but also prophylactically as a Excellent for the gut thus inhibit their absorption and resultantstandard additive in fish feed. Brewers’ yeast cells are like miniature metabolic harm. Last but not least, the for- The intensive farming methods used for power houses, and are responsible for the mation of a biofilm on the intestinal mucosafish cultivation in aquatic environments with alcoholic fermentation that takes place during enhances this protective barrier againsta direct connection to the groundwater are the brewing stage of beer production. In the pathogens.especially liable to facilitate the very rapid course of the fermentation of malt extract,and direct spread of problematic production high concentrations of minerals and trace Glucan and the immune systemresidues to humans. Resistant pathogens and elements, amino acids and nucleotides, B The cell wall of brewers’ yeast com-germs do not just limit the effectiveness of vitamins and enzymes, as well as many micro- prises approximately 20-25 percent mannans 40 | InternatIonal AquAFeed | May-June 2012
  3. 3. WHO CARES... …If profits in the aquaculture industry are as appetising as a sea bass dinner? As feed prices soar and formulation moves towards sustainability, aquaculture producers must maximise feed efficiency to stay on the menu. In all phases of the fish’s life, proper nutrition will improve health. With decades of dedicated research, the “Alltech Aqua Advantage” programme responds to the challenges of today’s aquaculture producers through nutritional innovation, addressing issues such as growth and performance, feed efficiency, flesh quality and immunity. So, when asked who cares about your profitability? Remember DOES! Silver Sponsor of XV International Symposium on Fish Nutrition and Feeding Molde, Norway • 4-7 June | | @Alltech
  4. 4. FEATURE Tests were recently performed on several species of fish that Oral administration tests Purified ß1,3/1,6(D)glucans enhance the confirm a stimulatory effect on the animals non-specific immune response. This is non-specific immune system of particular value in the fish farming industry, as there are multiple stress and environmen- tal factors that impact and stress the fish. If they become infected, the specific immune system is only able to respond slowly and inadequately. In such situations, a heightened non-specific capability can support or acceler- ate the specific immune response and the production of specific antibodies. Fish are subject to similar, added stresses during vaccinations too. A study by Siwicki et al. (2011) investigated the effect of orally administered ß1,3/1,6(D)glucan (100mg orand 25-30 percent ß-glucans. ß1,3/1,6(D) ß-glucan products is not only the source and 200mg Leiber® BetaS per kg of feed) on theglucan molecules can be isolated from it using characteristic molecular structure, but also the antibody secreting cells (ASC) and specificspecial hydrolytic processes. The molecules purity of the product. A minimum content of antibody titres after immunisation of rainbowconsist of characteristic (1,3)-beta-glycosidic 70 percent pure ß1,3/1,6(D)glucan should be trout fingerlings (Oncorhynchus mykiss) bylinked D-glucose subunits connected with aimed for. The standard grade Leiber® BetaS immersion with anti-enteric redmouth diseasewith irregular beta-(1,6)-linked side chains of has a ß-glucan content of 80 percent. The met- vaccine (AquaVac ERM). Inoculation was per-various length. Only this free ß-glucan struc- abolic activity of this product has already been formed one week after the start of administra-ture from Saccharomyces cerevisiae has an tested on many animal species and verified. tion with Leiber® BetaS.immunomodulatory effect on the metabolism. Tests were recently performed on sev- These two parameters were measured In contrast with intact yeast cells or man- eral species of fish that confirm a stimulatory on day seven, 14, 21, 28 and 40 in thenan-oligosaccharides, free ß1,3/1,6(D)glucan effect on the non-specific immune system. blood serum and adrenal glands. Both dos-molecules are able to pass through the pro- Rainbow trout and carp received 0.02 percent age levels stimulated the number of specifictective epithelial barrier in the gut with the ßglucan (Leiber® BetaS) administered in their ASCs and specific antibody levels, wherebyhelp of specialised M cells. In gut-associated feed ration. The potential killing activity of 0.02 percent Leiber® BetaS in the fishlymph tissue (GALT), ß-glucans act like anti- phagocytes, the proliferative response of T feed was more effective. In each case thegens, stimulating specific macrophage recep- and Blymphocytes and the concentration of improvements were significant from day 21tors with their characteristic surface structures immunoglobulins and lysozymes in the blood onwards.(epitopes) (Engstad and Robertsen 1993). A serum was measured four weeks and eight The beneficial effect of ß1,3/1,6(D)glucancascade of immune responses is triggered, weeks after beginning administration. In two is well known in the fish nutrition industry. Theand non-specific immune system cells such as repetitions, a significant stimulation of these administration of 0.02 percent Leiber® BetaSmonocytes, natural killer cells, B-cells, T-cells parameters was demonstrated in both rain- in fish feed activates the non-specific immuneor lysozymes are released or activated. They bow trout and carp. status of the fish on the one hand, and onput the animal on a high state of alert and In subsequent infection studies using two the other, acts as an adjuvant during vaccina-preparedness to defend against all types of bacterial (Aeromonas salmonicida; Yersinia tions, thus enhancing the immunocompetenceforeign attack. What differentiates this from ruckeri) and one viral pathogen (IPN virus), of the fish. Its safe and simple method ofan actual infection is that ß-glucan does not the survival rate of rainbow trout and carp use, as well as the fact that ß-glucan frompossess any pathogenic properties, and acts with 0.02 percent Leiber® BetaS in their feed Saccharomyces cerevisiae is harmless to fishwithout causing any adverse health effects. showed an absolute increase of 30-40 percent and the environment, will become yet more A quality criterion for the effectiveness of (Siwicki, et al. 2008; Siwicki, et al. 2009). important in the future. ■ 42 | InternatIonal AquAFeed | May-June 2012
  5. 5. FEATURE AquaStar ® Fast growth in improved environment! Probiotic strains to support gut health. Biodegrading strains and enzymes to stabilize water quality and pond bottom. • Im pr an oved gu d pe • Im rform t health prov ance • Co ed w n ater qual ba trol of pa ity cteri thog a enic aquastar.biomin.netNaturally ahead May-June 2012 | InternatIonal AquAFeed | 43
  6. 6. This digital re-print is part of the May | June 2012 edition of International LINKSAquafeed magazine. Content from the magazine is available to view free-of-charge, both as a fullonline magazine on our website, and as an archive of individual features onthe docstoc website.Please click here to view our other publications on VO L U M E 1 5 I S S U E 3 2 0 1 2 • See the full issue • Visit the International Aquafeed website Transfering Vitamin C from fish to embryos Oxygenation technology – poised to transform aquaculture worldwide • Contact the International Aquafeed Team Ornamental fish and invertebrates for home aquaria Brewers’ yeast as a • Subscribe to International Aquafeed supplement in aquaculture THE INTERNATIONAL MAGAZINE FOR THE AQUACULTURE FEED INDUSTRYIAF12.03.indd 1 14/05/2012 18:05To purchase a paper copy of the magazine, or to subscribe to the paperedition please contact our Circulation and Subscriptions Manager on the linkabove. INFORMATION FOR ADVERTISERS - CLICK HERE