Why check selenomethionine levels in selenium yeast?


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Selenium yeast is commonly used in aquaculture to improve animal performance and meat quality. Samples of different selenised yeast products were sourced in the EU and USA. QA departments of Trouw Nutrition International and Selko Feed Additives performed a laboratory analysis on these. Outcomes revealed remarkable differences between product samples on most effective and active compound, namely selenomethionine (SeMet).

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Why check selenomethionine levels in selenium yeast?

  1. 1. November | December 2012 Why check selenomethionine levels in selenium yeast? 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. FEATURE Why check selenomethionine levels in selenium yeast? by Wilbert Litjens, Technical manager Optimin & Betaine and Paul Perucchietti, Product manager Optimin, Selko Feed Additives, The NetherlandsS elenium yeast is commonly used proteins and subsequently, tissues such as fillet Benchmark in aquaculture to improve animal or organs will be enriched with the selenium. Several samples of selenised yeast were performance and meat quality. This selenium is easily available when required sourced from the market and analysed Samples of different selenised yeast for the synthesis of selenoproteins (Figure 1). for the most relevant selenium species atproducts were sourced in the EU and This saves valuable time and ensures a fast and the University of Pau, CNRS, France. ThisUSA. QA departments of Trouw Nutrition effective reaction in case of stress or a disease. research lab is known as professional andInternational and Selko repeatable for organic seleniumFeed Additives performed species determination.a laboratory analysis on The value of selenised yeastthese. Outcomes revealed was determined by the levelsremarkable differences of total selenium, SeMet, SeCysbetween product samples and inorganic selenium. A totalon most effective and of 11 samples from differentactive compound, namely batches of a number of pro-selenomethionine (SeMet). ducers were examined. Samples were randomly numbered and Selenium is one of the sent to the lab for analysesessential trace elements in by HPLC ICP-MS. Results areaquaculture. It can be added shown in Table 1. Most interest-to aquafeed in two forms; ing is the variation in levels ofas inorganic selenite or as SeMet. Some samples containedorganic selenium yeast. Each only half the level of SeMetform has different metabolic compared to other samplesroutes and effects. (range from 24.8% to 69.7%). Organic selenium - selenised SeCys levels are, as expected, Table 1:yeast - is regarded as a more marginally present at all equaleffective way of supplementing Total Inorganic levels. Unexpectedly, Sample 6 SeMet SeCys Sample Selenium Seleniumselenium. With more frequent contained a relative high level ofusage of selenised yeast and ppm as % of ppm as % of % of total inorganic selenium (13.3%). ppm Se total Se Se total Se Seincreasing amount of suppliers,benchmarking on quality Need ofbecomes relevant. Selenised 1 3000 2090 69.7 140 4.6 < 2% selenomethionineyeast mainly consists of 2 2260 1460 64.6 100 4.4 < 2% Yeast is enriched with seleni-selenomethionine (SeMet), um through growing it in a medi- 3 2250 1110 49.1 70 3.3 < 2%which can be converted um with a controlled amountinto selenocysteine (SeCys) 4 1910 920 48.3 190 9.7 < 2% of selenium and a shortage ofby natural turnover from 5 1890 1160 61.2 670 3.5 < 2% sulphur. If the yeast grows, itmethionine into cysteine. 6 1990 490 24.8 < 10 - 13.3% must synthesise methionine withSeMet is regarded by animals 7 2217 1069 48.2 51 2.3 < 2% selenium incorporated; SeMet.as normal methionine and The higher the SeMet levels, the 8 2377 1278 53.8 87 3.7 < 2%absorbed and processed more beneficial the yeast will befollowing the methionine 9 2191 1092 49.8 59 2.7 < 2% as an organic selenium sourcepathway. The SeMet will 10 2027 854 42.1 49 2.4 < 2% for aqua species.be stored as methionine in 11 2239 1275 57.0 81 3.6 < 2% It is widely accepted in 26 | InternatIonal AquAFeed | november-December 2012
  3. 3. FEATURE and of minor when selenium enriched human foods such importance. The as fish fillets are marketed, consistent and remainders are high selenomethionine levels in the yeast feed SeMet precur- is essential to make health claims on these sors and SeCys/ foods. SeMet intermedi- A trial with rainbow trout evaluated differ- ate amino acids. ent sources of selenium and their subsequent Most of these effect on selenium levels in the fillet. Results compounds are are presented in Figure 2 (feeding level in less or not valua- ppm), showing a significant enrichment with ble to the animal Optimin SeY over another selenised yeast and and are individu- inorganic selenium. ally present at very low levels in Conclusion yeast. The benchmark revealed large differences in quality and consequently nutritional valuescientific literature that SeMet is the most Guaranteed high quality of different products. It is beneficial for a fisheffective and active compound in selenised Selko Feed Additives markets its own feed company or fish producer to compareyeast bringing beneficial effects to organism. premium quality selenised yeast; Optimin suppliers on SeMet levels and subsequentThe percentage of SeMet of total Se is the SeY. On every batch, as well total selenium pricing. Choosing a product which guaran-best indicator for the value and bioavailability as selenomethionine content is checked. tees selenomethionine is the best choice. Itof the selenium out of the yeast. Minimal 63 percent selenium of total sele- gives maximal benefits to animals, enriches The analysis of the main organic selenium nium must be in the form of SeMet for the animal products and lowers the cost of feedmetabolites (SeCys and SeMet) in relation batch to be released for customers. This formula.to the total selenium level gives a strong defined quality guarantees that aqua speciesevaluation on the success of the enrichment will get the most out of the selenium yeastprocess during production. Most selenised (Figure 2).yeast products contain 97-99 percent organic A consistent and high level of SeMet offers More InforMatIon:selenium of total selenium. numerous advantages. For example, when for- Email: wilbert.litjens@nutreco.com The dominant organic selenium form is SeMet, mulating feed a lower inclusion level is needed Website: www.selko.comwhich can be accurately (< 5% variation) deter- to meet requirements and saves costs withoutmined. SeCys is present at fixed, low levels (2-5%) compromising animal performance. Besides, 50.&2$6*(7 ,9:9,9#;<: 8 !"##"$%&""%"&&()("*)+ !""#$%&#()&*#(+#,%-$(.&/012#$(#-(3*#"0&$4 !"#$%&()*+,")*"-+-$& !"#$%"&&(")*"+ november-December 2012 | InternatIonal AquAFeed | 27
  4. 4. This digital re-print is part of the November | December 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 www.docstoc.com. VO L U M E 1 5 I S S U E 6 2 0 1 2 • See the full issue An overview of the UK fish vaccination industry • Visit the International Aquafeed website Why check selenomethionine levels in selenium yeast? Extrusion technology for the production of micro-aquatic feeds • Contact the International Aquafeed Team and shrimp feeds EXPERT TOPIC – Salmon • Subscribe to International Aquafeed THE INTERNATIONAL MAGAZINE FOR THE AQUACULTURE FEED INDUSTRYIAF12.06.indd 1 07/11/2012 17:39To 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 www.aquafeed.co.uk