Institute of Animal Nutrition and Physiology, Christian-Albrechts-University, Germany.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2009 Jan;26(1):119-26. doi: 10.1080/02652030802320600.
Previous studies have indicated that high concentrate feeding reduces the ruminal degradation of the mycotoxin ochratoxin A (OA) to the less-toxic ochratoxin alpha (Oalpha) in ruminants. This is due to a pH-induced decrease in ruminal protozoa and subsequent increasing transfer of OA into the systemic circulation. The present study investigated whether stabilization of rumen pH by the live yeast cell supplementation to high concentrate diets affects the toxicokinetics of OA in sheep. Sheep were fed diets consisting of 70% concentrates and 30% grass silage (dry matter basis) supplemented without or with live yeast cells (Saccharomyces cerevisiae CNCM I-1077). After an adaptation period of 3 weeks, animals were given a single dose of OA (2.46 mg) in the form of contaminated wheat. Even though live yeast cells accelerated the recovery of ruminal pH from the decrease in pH induced by feeding, no effect on ruminal degradability and systemic availability of OA was recorded. Based on in vitro studies, live yeast cells and extracts of live yeast cell walls have been suggested as a mycotoxin-binding agent. However, supplementation with live yeast cells had no effect on the excretion pattern of OA in sheep, indicating that binding of OA to yeast components may be limited in ruminants. With respect to the toxicokinetics of OA, our results are in agreement with earlier results demonstrating that the hydrolysis of OA in the gastrointestinal tract of sheep is substantially less than previously described, especially if OA is ingested in combination with concentrate-rich diets. Our study demonstrates that feeding a live yeast cells product, registered as a feed additive for improving zootechnical performance, had no impact on the toxicokinetics of OA under the chosen conditions.
先前的研究表明，高浓度饲养会降低瘤胃中原霉素 A（OA）向较少毒性的原霉素 alpha（Oalpha）的降解，这是由于 pH 值降低引起的瘤胃原生动物减少，以及随后 OA 向全身循环的转移增加。本研究探讨了高浓度日粮中添加活酵母细胞稳定瘤胃 pH 值是否会影响绵羊 OA 的毒代动力学。绵羊喂食由 70%浓缩饲料和 30%草青贮（干物质基础）组成的日粮，不添加或添加活酵母细胞（酿酒酵母 CNCM I-1077）。经过 3 周的适应期后，动物口服 OA（2.46mg）污染的小麦。尽管活酵母细胞加速了因喂养而降低的瘤胃 pH 值的恢复，但未记录到对 OA 的瘤胃降解率和全身可利用性有影响。基于体外研究，活酵母细胞及其活酵母细胞壁提取物已被认为是一种霉菌毒素结合剂。然而，在绵羊中添加活酵母细胞对 OA 的排泄模式没有影响，表明 OA 与酵母成分的结合可能在反刍动物中受到限制。就 OA 的毒代动力学而言，我们的结果与早期结果一致，表明绵羊胃肠道中 OA 的水解作用明显低于先前描述的，特别是如果 OA 与富含浓缩饲料的日粮一起摄入。我们的研究表明，在选择的条件下，作为改善动物生产性能的饲料添加剂注册的活酵母细胞产品的喂养对 OA 的毒代动力学没有影响。
