Responses of pigs fed wheat naturally infected with Fusarium graminearum and containing the mycotoxins 4-deoxynivalenol and zearalenone

Abstract

Wheat naturally infected with Fusariurn graminearurn on a farm in south-eastern Queensland contained mean concentrations of 23 mg 4-deoxynivalenol (DON) kg-1 and 4 mg zearalenone (ZEA) kg-1. No other mycotoxins were detected. The wheat was incorporated into diets containing DON ranging from 0-14 mg kg-1 and corresponding ZEA concentrations. Diets were fed in two experiments to a total of 66 pigs of an improved synthetic breed (half each sex, initial liveweights about 27 kg). The first experiment lasted 14 days and tested short-term responses, while the second was a growth trial lasting up to 14 weeks. Pigs were fasted for 24 h before the diets were first offered. In the first experiment, the pigs ate readily for 10-15 min and thereafter sparingly or not at all for several hours. Vomiting commenced in pigs consuming the most DON after 10-20 min and continued for the next hour. A similiar pattern was seen in the growth trial. In total, vomiting was observed in 13 pigs on the first day of feeding, but not thereafter. Vomiting was accompanied by signs of abdominal distress and teeth grinding. This was followed by marked feed refusal, the extent being related linearly to increasing DON concentrations, so that pigs offered the most DON lost weight during the growth trial. Voluntary feed intake was depressed by about 6% for each 1 mg kg-1 of dietary DON, although some tolerance developed over time. Slight diarrhoea was noted in some pigs, and a few females showed oestrogenic effects due to the ZEA. The feed refusal was well correlated with that obtained by other workers using purified DON. Feed conversion was not adversely affected until DON concentrations exceeded about 8 mg kg-1.

Effective use in livestock feeds of mouldy and weather-damaged grain containing mycotoxins—case histories and economic assessments pertaining to pig and poultry industries of Queensland

“…No vomiting occurred but voluntary feed intakes (VFI) were only half of those of pigs on control feed. Except for failure to cause vomiting, these results were similar to those we had obtained with equivalent concentrations of deoxynivalenol in wheat (Williams et al 1988). However, in contrast to the deoxynivalenol results, a worsened feed conversion contributed to a greater impact on growth rate.…”

“…data). The effect of deoxynivalenol on pigs is to reduce feed intake without affecting feed conversion except at >8 mg kg-l. We have calculated that voluntary feed intake is depressed by 6% for each 1 mg kg-' of dietary deoxynivalenol in the early stages of feeding, although some tolerance develops over time (Williams et al 1988). Performance over the 20-50 kg period and the cost of this to a pig farmer can be seen in Table 4.…”

“…Concentrations of 1-5 mg kg-' will induce pseudo-oestrus in about 4-7 days (Young et al 1981;Blaney et al 1984a;Williams et al 1988). Concentrations of 5-20 mg kg-' may reduce fertility of sows and boars (Chang 1979).…”

A review of potential contaminants in Australian livestock feeds and proposed guidance levels for feed

“…Young female pigs appear to be the most susceptible class of animal to ZEA, where oestrogenic effects can be produced at concentrations of 0.2 mg/kg in the total diet although these effects are more consistent at 1 mg/kg (Williams et al 1988;Williams and Blaney 1994). In some field cases, effects are associated with even lower concentrations (0.1 mg/kg) and it appears that once young pigs have ingested sufficient ZEA to induce pseudo-oestrogenism that lower concentrations can maintain that condition (Biehl et al 1993).…”

“…The tolerance of pigs to both DON (Williams et al 1988) and NIV (Williams and Blaney 1994) in naturally contaminated grain in Australia has been tested. Results were similar in type and magnitude to those reported elsewhere.…”