Effects of <i>Fusarium</i> toxin contaminated wheat grain and of a detoxifying agent on rumen physiological parameters and <i>in sacco</i> dry matter degradation of wheat straw and lucerne hay in wethers

Abstract

Wethers equipped with a rumen fistulae were subjected to four dietary treatments in consecutive experiments. The treatments consisted of rations containing wheat grain and pasture hay at a ratio of 1 to 1 on a dry matter basis. Two wheat grain batches were fed either in the absence or presence of a detoxifying agent (Mycofix^Plus, Biomin GmbH, Herzogenburg, Austria). One wheat grain batch served as the uncontaminated control wheat whereas the other batch contained the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) at concentrations of approximately 10 and 0.76 mg per kg dry matter, respectively.Parameters of rumen fermentation such as the molar ratios of short chained volatile fatty acids and ammonia concentration in rumen fluid remained unchanged in response to dietary treatments whereas the detoxifying agent exerted a rumen pH-buffering effect. This effect was independent of the mycotoxin contamination of the wheat. The pH-differences in rumen fluids collected from wethers fed the MP-supplemented and unsupplemented rations amounted 0.2 to 0.3 on average in the time period between 1.5 and 5 h after feeding.The kinetic profile of the in sacco dry matter degradation revealed a reduced degradation rate for wheat straw incubated in wethers fed the mycotoxin contaminated rations whereas no changes were obvious when lucerne hay was incubated. The detoxifying agent had no effect on the kinetics of dry matter degradation.It can be concluded that feeding of rations containing approximately 4.6 mg of DON and 0.34 mg ZON per kg of complete ration at a reference dry matter content of 88% does not impair rumen fermentation although there was a trend for a decrease in the rate of dry matter degradation of the slowly degradable wheat straw. The pH-buffering effects of the detoxifying agent were mycotoxin independent.KEY WORDS: Fusarium toxin, rumen parameters, in sacco, degradability 438 FUSARIUM TOXIN AND RUMEN PARAMETERS

Effects of concentrate proportion in the diet with or withoutFusariumtoxin-contaminated triticale on ruminal fermentation and the structural diversity of rumen microbial communitiesin vitro

“…Therefore, DON concentrations lower than 5 mg per kg seem to not affect rumen fermentation, with the exception of fibre fractions. This fact was reflected by the unchanged amounts of SCFA both in the present in vitro and earlier in vivo studies (Da¨nicke 2002;Da¨nicke et al 2005). In contrast, higher fermentation rates (Seeling et al 2006) and differences in feed intake (Keese et al 2008b) changed the pattern of SCFA when toxin-contaminated grain was fed.…”

Effects of level of feed intake and Fusarium toxin‐contaminated wheat on rumen fermentation as well as on blood and milk parameters in cows

“…They found a decrease in SCFA production and a reduction in gas production. Dänicke (2002) reported that rumen pH and concentrations of ammonia and SCFA in wethers fed a ration of hay and Fusarium toxin‐contaminated wheat (4.6 mg of DON and 0.34 mg ZON per kg of ration DM) were not influenced by contamination of the wheat. Accordingly, the Fusarium contamination did not modify ruminal pH of dairy cows in the current study (Fig.…”

“…Several studies have shown that Fusarium infection of wheat can lead to alterations of nutrient composition and cell wall compounds of the infected grain because of higher protease, amylase and several non‐starch polysaccharide (NSP)‐degrading enzyme activities (Kang and Buchenauer, 2000; Matthäus et al., 2004). However, knowledge regarding the effects of Fusarium ‐contaminated feed and/or DON and ZON on ruminal nutrient utilization (Dänicke, 2002; Dänicke et al., 2005) and milk composition (Noller et al., 1979; Cote et al., 1986; Whitlow et al., 1986; Charmley et al., 1993; Ingalls, 1996) is still lacking. Moreover, no information is available about effects of a passage‐rate‐dependent ruminal fermentation of Fusarium ‐contaminated feed.…”

Effect of Fusarium toxin‐contaminated triticale and forage‐to‐concentrate ratio on fermentation and microbial protein synthesis in the rumen

“…Immediately before the morning feeding, a lower concentration of acetate with inclusion of FUS was also observed in the present study with cows (data not shown, p = 0.06). Studies with sheep, however, showed no significant effects of Fusarium toxin‐contaminated wheat on the acetate‐to‐propionate ratio (Dänicke, 2002). Variable results in SCFA production could be attributed to interactions of Fusarium toxins with other factors such as the composition of diet, the dosage and duration of toxin exposure and the animal species (Seeling and Dänicke, 2005).…”