Time-dependent effects of graded levels of Fusarium toxin-contaminated maize in diets for female piglets
The study was conducted to evaluate the effect of graded levels of the Fusarium toxins zearalenone (ZEA) and deoxynivalenol (DON) in diets for female piglets during 29 days of treatment on the development of performance, organ weights, clinical serum characteristics, differential blood counts and vulva morphology. For this purpose, 120 female weaned piglets with an initial mean bodyweight of 8.9±1.6 kg, were assigned to 5 feeding groups (n=24). The piglets of groups 1 to 5 received diets containing 0, 1.25, 2.5, 5 and 10% naturally contaminated maize instead of control maize, resulting in 0.01, 0.05, 0.08, 0.17 and 0.29 mg ZEA/kg, and 0.03, 0.59, 1.27, 2.01 and 4.52 mg DON/kg feed, respectively. After 1, 3, 8, 15, 22 and 29 days, 20 piglets (four piglets from each group) were slaughtered. Animals of group 5 consumed at least 20% less feed than animals of the other feeding groups. Body weight gain was significantly reduced in group 5 in the last week compared to group 2 and 3. Relative visceral organ weights were not affected by the treatments, but they mostly showed some minimal time dependent alterations. Uterus weights tended to be decreased in group 5 on day 15 of the experiment. Though not significant, signs of hyperoestrogenism such as swelling of the vulva became more pronounced with increasing time of exposure. Histopathological examination of organ specimens did not reveal any toxin related lesions. Total leukocytes, differential blood count and stimulation index of peripheral blood mononuclear cells were not affected by the diet, however, the proportion of lymphocytes increased while neutrophils decreased during the experiment independent of treatment. Clinical chemical serum characteristics were not affected by the treatments, however, they were somewhat affected by time. In conclusion, the dose related effects of ZEA and DON on performance and signs of hyperoestrogenism seemed to be dependent on exposure time.