Effects of storage conditions on the mycotoxin contamination of straw as a potential exposure source for pigs

Publication Type

Contribution to conference

Authors

Rohweder D., Valenta H., Sondermann S., Schollenberger M., Drochner W., Dänicke S.

Year of publication

2008

Published in

10. Tagung Schweine- und Geflügelernährung

Editor

Klaus Eder

Pubisher

Universitätsdruckerei , Halle (Saale)

Band/Volume

10./

Series/labeling

Schweine- und Geflügelernährung (Martin-Luther-Universität Halle-Wittenberg)

ISBN / ISSN / eISSN

13: 978-3-86829-075-2

Page (from - to)

184-185

Conference location

Halle (Saale)

Conference date

18.11.2008

Keywords

mycotoxins, pig, Stroh

IntroductionMycotoxins are well known to cause problems in pigs such as decreased feed intake and performance and a lower resistance to diseases because of their frequent occurrence in feed at toxicological relevant concentrations. However, grain is not the only constituent of the plant contaminated with mycotoxins after fungal infection. Also other parts, i.e. straw and chaff, could be contaminated by mycotoxins.Straw can be beneficial for the welfare of pigs through reducing aggressions and stereotypes. Intake of straw from bedding material was estimated to range from 50 g/d up to nearly 600g/d for 25kg pigs, depending on estimation method and diet (Staals et al., 2007). Furthermore, diets diluted with straw fed ad libitum could be used as an alternative to restrictive feeding by reducing dietary level of energy without any losses in performance (Hakansson et al., 2000).Thus, the present project aims to scrutinize on the potential mycotoxin exposure of pigs by straw and potential sources of straw mycotoxin contamination. The present experiment focuses on the storage of different pre-harvest straw qualities.Material and MethodsResultsOnly the mycotoxins ZON, DON, 15-AcDON and 3-AcDON were detected in the samples. NIV was only found in a few samples slightly above the detection limit with no correlation to storage variant or straw type. The other ten analysed mycotoxins were all below the detection limit.ZON was detected in each sample with higher concentrations in the F-straw (855 µg/kg DM [dry matter]) than in the C-straw (269µg/kg DM). Furthermore, during outdoor storage (O), a significant increase of the ZON concentration occurred in both types of straw (CO, FO) ranging from 97µg/kg DM up to 983µg/kg DM and from 765 µg/kg DM up to 1295 µg/kg DM, respectively, over the course of storage (Fig.1).Compared to ZON, the mycotoxins DON, 15-AcDON and 3-AcDON showed only significant differences between not inoculated and inoculated straw, with average concentrations of 724 µg/kg DM, 39 µg/kg DM and 19 µg/kg DM in the C-straw and 31788 µg/kg DM, 101 µg/kg DM and 3390 µg/kg DM in the F-straw (Fig.2).While the DM of the straw stored in barn persisted at approximately 84%, the DM decreased significantly in the straw stored outdoor. The DM of the F-straw decreased to 66%, in the C-straw to even 47% (Fig.1). Moreover, there was a negative correlation between the ZON concentration and the DM, which could also explain the increase of ZON over the storage period outdoor.ConclusionDON and ZON were the most abundant mycotoxins. While the DON concentrations were only influenced by the straw type with consistently higher values in the F-straw, the ZON concentrations also increased with storage time due to unfavourable storage conditions characterized by a significant water uptake by straw. Depending on the amount and the mycotoxin contamination degree of straw accessible for the animals, pigs could be exposed significantly to mycotoxins by this exposure route.