PSII-21 Metabolites of <i>Kazachstania slooffiae</i> reduce tight junction integrity in piglet intestinal epithelial cells

Abstract The weaning transition is an inherently stressful event and can cause considerable growth reductions. Kazachstania slooffiae, a fungus identified as a prominent commensal microbe in the gastrointestinal tract of piglets during weaning, has beneficial interactions with other microbial community members associated with piglet health. To test if K. slooffiae may also contribute to host health through direct means, the supernatant fraction or cellular debris fraction of heat-killed K. slooffiae grown in vitro using yeast-peptone dextrose (YPD) was administered to swine intestinal epithelial cells (IPEC-J2 cells from the Leibniz Institute DSMZ). Transepithelial electrical resistance (TEER) was measured before treatment, and then at 4 h, 12 h, and 24 h post-treatment using transwell plates to assess the integrity of tight junctions. After 24 h, FITC-dextran was also used to assess permeability. Lactate dehydrogenase was assayed to measure cell viability, and media and cells were collected for cytokine release and gene expression, respectively. Cells were subjected to one of six treatments: control media (CM), a 1:1 mixture of YPD and CM (MIX), a high dose of YPD culture media from K. slooffiae mixed 1:1 with CM (high media – HM), a 1:100 dilution of HM mixed with CM (low media – LM), a high concentration (1x106 CFU/mL) of heat-killed cellular debris in CM (high cells – HC), or a 1:100 dilution of HC in CM (low cells – LC). When subjected to either MIX or HM, TEER decreased and did not recover relative to cells grown in CM, LM, HC, or LC (P &amp;lt; 0.05). However, permeability of FITC-dextran was greatest in HM relative to all other treatments (P &amp;lt; 0.05). Cell viability was comparable between groups after 24 H (P &amp;gt; 0.05), indicating cell death did not contribute to increases in permeability. Results are pending for cytokine release and gene expression. Together with past data, results shown here with this model suggest that metabolites generated from K. slooffiae growth may positively impact microbial community members rather than support intestinal epithelial cells in the piglet during the weaning transition. Moreover, without a protective mucosal barrier, heat-stable metabolites from K. slooffiae may lead to reductions in tight-junction integrity in the piglet.