Technical note: Development of a feed matrix as inoculum in infection studies in piglets.

Current methods used for oral administration of pathogens to piglets are stressful for the animals because of fixation and use of inoculation methods such as oral gavage. In the present study an alternative way to challenge piglets with Typhimurium (ST) is investigated. The strategy was to incorporate the in a feed matrix, which is fed to the piglets and eaten voluntary. Different types of feed matrices were tested for their absorption capacity, handling properties, and palatability to piglets. Furthermore, the viability of ST in feed matrices was studied. The ST could be incorporated in ladyfinger biscuits; a 2-cm piece absorbs 1 mL of culture media. The ladyfinger biscuits were very well accepted by the piglets. After a short training period, the piglets consumed the -incorporated biscuits out of the feeding trough. In this way the animals were infected in a more natural way and without stress. The safety of farm workers was also increased because the incorporated ST results in less spoilage and spreading of ST during the infections. Results indicated that the ST cell count was reduced by only 0.2 log unit to 8.7 log cfu per inoculum after 24 h at 4°C incorporation of ST into the biscuits, which is sufficient for an infection study and indicates excellent viability of the . The viability was also indicated by increased fecal shedding of ST. Thus, it is concluded that ladyfinger biscuits are a suitable matrix to challenge piglets with ST.