Effect of Feeding Saccharomyces cerevisiae boulardii CNCM I-1079 to Sows and Piglets on Piglets’ Immune Response after Vaccination against Actinobacillus pleuropneumoniae

SIMPLE SUMMARY: The production of high-quality pigs starts with sow nutrition. In this study, we tested the effect of feeding the live yeast Saccharomyces cerevisiae boulardii CNCM I-1079 to sows and their piglets on litter performance and some immunity parameters of piglets vaccinated against Actinobacillus pleuropneumoniae. Our results indicate that feeding lactating sows with the live yeast improves litter growth and weaning weight. For that reason, the pigs are likely better prepared for the challenges they are going to encounter after weaning. The piglets from supplemented sows show higher mucosal protection and less inflammation in the lung after the vaccine, explained by the gut–lung axis, which is defined as the cross-talk between the gut microbiota and the lung. ABSTRACT: The aim of this study was to assess the effect that feeding Saccharomyces cerevisiae boulardii CNCM I-1079 (LSB) to lactating sows and their progeny has on inflammatory response and mucosal immunity after vaccination against Actinobacillus pleuropneumoniae. Sixty-seven Danbred sows were allotted into two treatments when they entered the farrowing room seven days before the expected farrowing date: control (CON: lactation diet) and LSB (CON + 12 × 10(9) colony forming units (CFU)/d until weaning). At weaning, piglets were equally allotted into two experimental diets according to sow diet: control (CON: 2-phase post-weaning diets) and LSB (CON + 2 × 10(9) CFU/kg and 1 × 10(9) CFU/kg in phases 1 and 2, respectively). The piglets were vaccinated at days 26 and 49 post-weaning. Growth performance and number of IgA producing cells and cytokine’s gene expression in lung, lymph node, and intestine samples at day 70 post-weaning were assessed and analyzed in SPSS Statistics 26: performance with a general linear model with sex, room, sow diet, piglet diet, and their interactions as main effects, and immunity with a Kruskal–Wallis test for k unrelated samples. Piglets from LSB-fed sows displayed a higher average daily gain (ADG; p < 0.01) and a heavier body weight (BW; p < 0.05) during lactation, tended (p < 0.1) to be heavier at day 49, and to have a higher ADG between days 26 and 49; had fewer number of IgA producing cells in the lymph node (p < 0.05); and all the cytokines studied were significantly under-regulated (p < 0.05) in the lung. It is concluded that feeding Saccharomyces cerevisiae boulardii CNCM I-1079 to sows improved piglet performance during lactation and showed a clear reduction in the inflammatory status of the lungs after vaccination against A. pleuropneumoniae, suggesting that there was a maternal imprinting effect on mucosal protection and a cross-talk between the gut microbiota and the lung.