Effet chez le porcelet d'une exposition à un régime co-contaminé en ...

INTRODUCTIONImprovement in FCR and less pronounced histological changes in kidneys, liver, bursa and spleenwere verified in animals fed the toxin deactivator. Thus in the presence of this feed additive, theharmful effects in the pathomorphological and histological changes in internal organs wereattenuated (Hanif et al., 2008).Zearalenone has no acute toxicity, but it mimics the reproduction hormone estrogen, andtherefore causes substantial fertility problems. The metabolisation of this toxin by T.mycotoxinivorans leads to a compound that is no longer estrogenic. This has been proven in an invitro assay with breast cancer cells (Schatzmayr et al., 2003).Reduction of zearalenone to α- and β-zearalenols has been shown in ruminal fluid and for manymixed and pure cultures of bacteria, yeast and fungi. However, this transformation cannot beconsidered as a detoxification as zearalenols still show significant estrogenic activity. Non-estrogenicZEA-metabolites were obtained from degradation by e.g. Thamnidium elegans, Mucor baineri,Rhizopus sp., Streptomyces rimosus, Cunninghamella baineri and Gliocladium roseum (Kamimura,1986; EI-Sharkawy and Abul-Hajj, 1987; 1988). The latter strain detoxified zearalenone by ringopening with subsequent decarboxylation in yields ranging between 80 and 90% (El-Sharkawy andAbul-Hajj, 1988).A great deal of literature is available concerning the biotransformation of trichothecenes, whichare among the world’s most important agricultural toxins. Their toxicity can mainly be attributed totheir 12,13-epoxide ring. Thus, reductive de-epoxidation by ruminal and intestinal flora of pigs, hensand rats (King et al., 1984; Kollarczik et al., 1994; Swanson et al., 1987, 1988; Yoshizawa et al., 1983)or by a new strain of Eubacterium isolated from bovine rumen contents (Binder et al., 2000) results ina significant loss of toxicity. The latter bacterium referred to as BBSH 797 is actually the first bacterialstrain cultured, produced and stabilized in order to be applied as feed additive to counteract thenegative effects of trichothecenes by biotransformation. Fuchs et al. (2000; 2002) identified nontoxicmetabolites after the microbial degradation of type A and type B trichothecenes by BBSH 797and showed that de-acetylation occurs simultaneously to de-epoxidation when the strain wasapplied. The in vivo efficacy of the additive has been tested in trials with pigs and chickens.Significant feed gain and improved feed conversion ratios were determined in piglets fed 2.5 mg/lDON and the chickens fed 10.5 mg/l DON showed reduced mortality and a positive influence onweight development (Binder et al., 2001; Plank et al., 2009). Moreover, a BBSH 797-containing feedadditive was capable of counteracting the adverse effects on performance of growing broilerchickens caused by the dietary administration of 2 ppm T-2 toxin (Diaz et al., 2005).Other investigations concerning microbial detoxification of trichothecenes concentrated on theuse of aerobic soil bacteria. He et al. (1992) incubated soil with DON and measured a significant85