Clinical impact of deoxynivalenol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol on the severity of an experimental Mycoplasma hyopneumoniae infection in pigs

BACKGROUND: The mycotoxin deoxynivalenol (DON) is highly prevalent in cereals in moderate climates and therefore pigs are often exposed to a DON-contaminated diet. Pigs are highly susceptible to DON and intake of DON-contaminated feed may lead to an altered immune response and may influence the pathogenesis of specific bacterial diseases. Therefore, the maximum guidance level in feed is lowest in this species and has been set at 900 μg/kg feed by the European Commission. This study aimed to determine the effect of in-feed administration of a moderately high DON concentration (1514 μg/kg) on the severity of an experimental Mycoplasma hyopneumoniae (M. hyopneumoniae) infection in weaned piglets. Fifty M. hyopneumoniae-free piglets were assigned at 30 days of age [study day (D)0] to four different groups: 1) negative control group (NCG; n = 5), 2) DON-contaminated group (DON; n = 15), 3) DON-contaminated and M. hyopneumoniae-inoculated group (DONMHYO; n = 15), 4) M. hyopneumoniae-inoculated group (MHYO; n = 15). The piglets were fed the experimental diets ad libitum for five weeks and were monitored during this period and euthanized at day 35 [27 days post infection (DPI)] or 36 (28 DPI). The main parameters under investigation were macroscopic lung lesions (MLL) at euthanasia, respiratory disease score (RDS) from day 8 until day 35, histopathologic lesions and log copies of M. hyopneumoniae DNA detected by qPCR, determined at the day of euthanasia. RESULTS: No significant difference was obtained for MLL at euthanasia, RDS (8-35), histopathologic lung lesions and log copies of M. hyopneumoniae DNA in the DONMHYO and MHYO group and consequently, no enhancement of the severity of the M. hyopneumoniae infection could be detected in the DONMHYO compared to the MHYO group. CONCLUSIONS: Under present conditions, the findings imply that feed contaminated with DON (1514 μg/kg) provided to weaned pigs for five weeks did not increase the severity of an experimental M. hyopneumoniae infection. Further research is needed to investigate the impact of DON on M. hyopneumoniae infections in a multi-mycotoxin and multi-pathogen environment.