Effects of graded levels of Fusarium toxin contaminated maize in diets for female weaned piglets

A dose response study was carried out with piglets to examine the effects of increasing amounts of Fusarium toxins in the diet on performance, clinical serum characteristics, organ weights and residues of zearalenone (ZON) and deoxynivalenol (DON) and their metabolites in body fluids and tissues. For this purpose, Fusarium toxin contaminated maize (1.2 mg ZON and 8.6 mg DON per kg maize) was incorporated into a maize based diet for piglets at 0, 6, 12.5, 25 and 50% at the expense of control maize. The experimental diets were tested on 100 female piglets allotted to 20 boxes (five animals per box) covering a body weight range of 12.4 +/- 2.2 kg to 32.5 +/- 5.6 kg. Voluntary feed intake and, consequently, body weight gain of the animals receiving the highest proportion of Fusarium toxin contaminated maize were significantly decreased while the feed conversion ratio was not affected by the treatment. The mean weight of the uterus related to the body weight of the animals of the same group was increased by almost 100% as compared to the control. For this group, significantly decreased values of total serum protein were determined, while the serum activity of the liver enzyme glutamate dehydrogenase and the serum concentration of the follicle stimulating hormone were decreased for all treatment groups receiving 6% contaminated maize or more in the diet. Serum concentrations of immune-globulins were not consistently altered by the treatment. Corresponding to the dietary exposure, increasing concentrations of ZON and alpha-zearalenol were detected in the bile fluid, liver and in pooled urine samples. The metabolite beta-zearalenol was detected only in bile fluid. The total concentration of ZON plus its metabolites in bile fluid correlated well with the diet contamination ( r = 0.844). DON was found in serum, bile fluid and pooled urine samples while de-epoxy-DON was detected only in urine. The serum concentration of DON correlated well with the respective toxin intake 3 - 4 h prior to slaughtering ( r = 0.957). For all mentioned analyses of residues it has to be noted that toxin residues were detectable even if negligible concentrations were present in the diet.