Ute Tiemann

In vivo and in vitro effects of the mycotoxins zearalenone and deoxynivalenol on different non-reproductive and reproductive organs in female pigs: A review

This review summarizes the toxicological data on the effects of the mycotoxins zearalenone (ZON), its metabolites, and deoxynivalenol (DON) on different parameters relating to reproductive and non-reproductive organs in female pigs. In vivo, 22 mg ZON kg−1 in the diet cause alterations in the reproductive tract of swine such as in the uterus, and affects follicular and embryo development. ZON and its metabolites have been shown to bind competitively to oestrogen receptors in an in vitro system. The feeding of pigs with a 9 mg DON kg−1-contaminated diet can act on protein synthesis, humoral and cellular immune response depending on dose, exposure and timing of functional immune assay, and affect liver and spleen cell structures. Beside these effects, reproductive alterations were observed in pigs, too. Both in vivo and in vitro exposure to DON decreased oocyte and embryo development. In vitro application of DON to uterine cells inhibits their proliferation rate and modulates the process of translation at a different molecular level when compared with the in vivo application. The histopathological results provide evidence of spleen and liver dysfunction in the absence of clinical signs, especially in pigs fed higher concentrations of Fusarium toxin-contaminated wheat. Prepuberal gilts react more sensitively to DON > ZON feeding compared with pregnant sows. In the liver, histopathological changes such as glycogen decrease and interlobular collagen uptake were only observed in prepuberal gilts, whereas enhancement of haemosiderin was found in both perpuberal gilts and pregnant sows. This review presents some of the current knowledge on the biological activities of ZON and DON in pig. Altogether, ZON affects reproduction of pigs most seriously because it possesses oestrogenic activity. However, DON affects reproduction in pigs via indirect effects such as reduced feed intake, resulting in reduced growth or impairment of function in vital organs such as liver and spleen.

The influence of the mycotoxins deoxynivalenol and zearalenol on in vitro maturation of pig oocytes and in vitro culture of pig zygotes.

The aim of the present study was to investigate the influence of specific toxins on in vitro maturation and embryo culture. alpha- and beta-zearalenol were tested at increasing levels from 3.75 to 90 microM and deoxynivalenol from 0.94 to 7.5 microM in order to evaluate the effect on in vitro maturation rate of porcine cumulus-oocyte complexes. Furthermore, the influence of alpha-zearalenol (3.75-30 microM) was appraised on the developmental competence of in vivo-derived zygotes during 5 days of in vitro culture. All three substances affected maturation and degeneration rates in a dose-dependent manner, but to different extents. Significant differences were obtained at a concentration of 7.5 microM alpha-zearalenol and higher. beta-zearalenol negatively affected the process of oocyte development beginning at a concentration of 30.0 microM (P<0.05). Deoxynivalenol had significant influence on oocyte maturation at a concentration of 1.88 microM (31.4 vs 79.3% for control). Differences in embryonic development in vitro were observed at a concentration of 15 microM alpha-zearalenol (P<0.05). These data demonstrate a negative effect of alpha-zearalenol on embryonic development of zygotes, and a compound-specific, dose-dependent negative effect of the three substances on meiotic progression of porcine oocytes.

Feeding of pregnant sows with mycotoxin-contaminated diets and their non-effect on foetal and maternal hepatic transcription of genes of the insulin-like growth factor system

The insulin-like growth factor (IGF) system regulates foetal and placental growth. It can be influenced by dietary factors, but little is known about the effects of mycotoxin feeding on hepatic levels of the IGF system. The aim was (1) to determine the normal foetal and maternal hepatic transcription of major IGF genes at distinct stages of pregnancy and (2) to find out if the mycotoxins deoxynivalenol (DON) and zearalenone (ZON) affect transcript concentrations. Pregnant sows were fed with naturally contaminated diets from days 35 to 70 (experiment 1), or from days 75 to 110 (experiment 2), or with control diets. Foetal hepatic IGF transcripts were determined at days 70 and 110, maternal transcripts at day 70 by quantitative polymerase chain reaction (qPCR). The highest levels of IGF-I transcripts were found in sows. On the contrary, IGF-II was predominantly expressed in foetuses at day 70. Expression of IGF-IR and IGFBP-3 decreased, whereas that of IGFBP-2 increased towards term. IGF-IIR and IGFBP-1 expression was similar in both foetuses and full-term piglets. IGF-IIR showed reduced levels in the maternal liver. The exposure of pregnant sows to DON- and ZON-contaminated diets significantly reduced the maternal and tended to reduce the weight gain of piglets in experiment 2, but had no effects on hepatic levels of IGF transcripts in both experiments. This suggests that mycotoxin-contaminated diets can induce growth depression in pigs during pregnancy without affecting hepatic transcription of major IGF genes.

Practically relevant concentrations of deoxynivalenol in diets for growing-finishing pigs offered as mash or pellets

Abstract A complete 2×3 two factorial design was applied to investigate the effects of Fusarium-infected wheat (2.5 mg DON/kg, 0, 25 and 50% of the diets), feed processing (mash and pellets) and the interactions thereof on fattening pigs (96, n = 16/group). Feed-to-gain ratio was significantly increased by contaminated wheat (2.65; 2.62 and 2.73 kg/kg for diets containing 0, 25 and 50%Fusarium-infected wheat, respectively) while digestibility of nutrients and metabolizable energy were not affected by the wheat batch. The feed processing also resulted in significant differences in feed-to-gain ratio but was accompanied by significant effects on the digestibility of organic matter and crude fat and on the metabolizable energy. Clinical chemical parameters were not significantly altered by the inclusion of the infected wheat. The lymphocyte proliferation capacity was not significantly affected by any of the experimental factors. A contribution of the feed processing to the variation of the deoxynivalenol (DON) effect may not be deduced from the present results.