Metabolism of aflatoxin, ochratoxin, zearalenone, and three trichothecenes by intact rumen fluid, rumen protozoa, and rumen bacteria

Abstract

The effect of rumen microbes on six mycotoxins (aflatoxin B,, ochratoxin A, zearalenone, T-2 toxin, diacetoxyscirpenol, and deoxynivalenol) considered to be health risks for domestic animals was investigated. The mycotoxins were incubated with intact rumen fluid or fractions of rumen protozoa and bacteria from sheep and cattle in the presence or absence of milled feed. Rumen fluid had no effect on aflatoxin B1 and deoxynivalenol. The remaining four mycotoxins were all metabolized, and protozoa were more active than bacteria. Metabolism of ochratoxin A, zearalenone, and diacetoxyscirpenol was moderately or slightly inhibited by addition of milled feed in vitro. The capacity of rumen fluid to degrade ochratoxin A decreased after feeding, but this activity was gradually restored by the next feeding time. Ochratoxin A was cleaved to ochratoxin a and phenylalanine; zearalenone was reduced to a-zearalenol and to a lesser degree to Izearalenol; diacetoxyscirpenol and T-2 toxin were deacetylated to monoacetoxyscirpenol and HT-2 toxin, respectively. Feeding of 5 ppm (5 mg/kg) of ochratoxin A to sheep revealed 14 ppb (14 ng/ml) of ochratoxin A and ochratoxin a in rumen fluid after 1 h, but neither was detected in the blood. Whether such conversions in the rumen fluid may be considered as a first line of defense against toxic compounds present in the diet is briefly discussed.

Growth, haematology, blood constituents and immunological status of lambs fed graded levels of animal feed grade damaged wheat as substitute of maize

“…Feeding ADW to lambs did not affect their health and growth, though mycotoxins contaminated cereals were reported to cause health and production problems. However, ruminant animals are more tolerant to dietary mycotoxins, and among the ruminant species, sheep has grater potential for mycotoxins tolerance (Kiessling et al, 1984;Battacone et al, 2003). The inclusion of ADW 353 g/kg diet replacing 75% maize in the diet of lambs exhibited better performance, However, the ADW inclusion at a level of 470 g/kg diet which totally replaced maize, caused growth depression approximately 19% and 33% compared to control and 353 g ADW diets respectively.…”

Plasma and Urinary Levels of Zearalenone and α‐Zearalenol in a Prepubertal Gilt Fed Zearalenone

“…DAS was identified according to Romer et al (1978). Zearalenol was identified according to Kiessling et al (1984). No DAS or zearalenol could be detected in the purified zearalenone.…”

“…The physiological activity of zearalenone and its oestrogenic congeners can be explained by the competition with 17P-oestradiol for the specific binding sites of the oestrogen receptor (Kiang et al 1978;Boyd & Wittliff 1978) and by interference with steroid-metabolizing enzymes (Kiessling & Pettersson 1978;Thouvenot & Morfin 1980;Olsen et al 1981). The purpose of the present investigation was to study the levels of zearalenone and a-zearalenol in blood plasma and their excretion into urine, during and after a low-dosage feeding.…”

“…The reduction of zearalenone is catalysed by 3ahydroxysteroid dehydrogenase (EC 1.1.1.50. ), which occurs as at least two multiple forms with different pH optima and subcellular locations (Kiessling & Pettersson 1978;Olsen et al 1981).…”

Occurrence, prevention and remediation of toxigenic fungi and mycotoxins in silage: a review

“…Rumen protozoa as well as rumen bacteria can metabolize various mycotoxins. 39 -42 However, the detoxifying capacity of the ruminal microflora is limited and varies with changes in the dietary composition or as a consequence of metabolic diseases like rumen acidosis. 1,41,43,44 Furthermore, as multiple mycotoxins such as patulin, roquefortine C, monacolins, beauvericin and enniatins exhibit antimicrobial properties, chronic exposure to such antimicrobial mycotoxins may disturb the ruminal microbiota and result in rumen acidosis, decreased feed efficiency and productivity, and even in clinical diseases like mastitis.…”