Effect of feeding regime on the metabolism of ochratoxin a during thein vitroincubation in buffered rumen fluid from cows

Abstract

Pure ochratoxin A (OA) was added to buffered rumen fluid collected from two fistulated cows and incubated under anaerobic conditions. Both animals were fed six diets containing grass, grass silage or hay, and two different amounts of concentrate consisting of barley and soybean meal. Four incubations per animal and diet were carried out at consecutive days. The concentration of OA declined exponentially to a very low or non-detectable level under all conditions examined, with half-lives at 0.51 to 2.76 h. The disappearance of OA was accompanied by the appearance of ochratoxin alpha (O alpha) with an average amount of O alpha formed relative to the disappearance of OA near 100%, independent of diet and animal. Based on four incubations per animal and diet the rate of OA disappearance was affected (P < 0.1) by the origin of rumen fluid from two animals, as well as by the type of basic component and amount of concentrate in the diet, with interactions between these factors. The disappearance of OA mostly was accelerated (P < 0.1) by replacing grass silage or hay by fresh grass and by increasing the content of concentrate from 10 to 50% of dry matter. It is concluded that the capacity of the rumen to detoxify OA is not limited by the yield of Oa from OA but is strongly dependent on animal and diet.

Relevance of the <i>Fusarium</i> toxins deoxynivalenol and zearalenone in ruminant nutrition. A review

“…This assumption is consistent with results of several in vitro studies with ochratoxin A (Müller et al, 1998(Müller et al, , 2001Özpinar et al, 1999). Müller et al (2001) added pure ochratoxin A to rumen fluid from cows which were fed six diets containing grass, grass silage or hay and two different amounts of concentrate consisting of barley and soyabean meal. The authors observed a disappearance of ochratoxin A accompanied by an appearance of ochratoxin α in the rumen fluid by replacing grass silage or hay by fresh grass and by increasing the level of concentrate in the total diet.…”

A Review on Mycotoxins in Food and Feed: Malaysia Case Study

“…Such effective deactivation explains the high tolerance of ruminants to OTA exposure (Hult and others ; Fink‐Gremmels ). Sometimes, small amounts of OTA may be found in milk that can be due to a protein‐rich diet that drastically affects the cleavage capacity by rumen microorganisms (Breitholtz‐Emanuelsson and others ; Muller and others ; Fink‐Gremmels ).…”

Mycotoxins in cattle feeds and carry-over to dairy milk: A review

“…This effective deactivation explains the high comparable high tolerance of ruminants to ochratoxin A exposure (Hult et al 1976;Pettersson et al 1982). Drastic changes in the feed composition, and a high percentage of protein-rich concentrates in the daily diet modify, however, the cleavage capacity of rumen microorganisms (Xiao et al 1991;Muller et al 2001), which explains why incidentally small amounts of ochratoxin A could be detected in milk (Skaug 1999).…”