Attempted Experimental Reproduction of Porcine Periweaning-Failure-to-Thrive Syndrome Using Tissue Homogenates

Porcine periweaning failure-to-thrive syndrome (PFTS) is characterized by anorexia and progressive debilitation of newly weaned pigs, of which some also demonstrate repetitive oral behaviour. Although no relevant porcine pathogens have been shown to be causally associated, inoculation of susceptible pigs using tissue homogenates is needed to rule out infectious etiologies. Eight snatched-farrowed porcine-colostrum-deprived (SF-pCD) pigs were inoculated with tissue homogenates made from PFTS-affected pigs orally, or combined orally, intraperitoneally (i.p.) and intramuscularly (i.m.) at day (D) 14 of age (INOC). On D21, i.p. and i.m. inoculation were repeated. Four sham-inoculated pigs served as control (CTRL). Three INOC pigs developed mixed bacterial septicemia between the first and second inoculation. All other pigs survived until termination on D49. Average daily gain (ADG) and the frequencies of diarrhea did not differ between INOC and CTRL pigs D14 and D29. Additionally, the progressive debilitation characteristic of PFTS was not observed in any pig, and repetitive oral behaviour was observed in both groups. In conclusion, PFTS was not experimentally reproduced by the current experimental approach providing evidence that PFTS may not have an infectious etiology.