Abstract: Yeast β-glucans may have beneficial effects on the immune response of gilts and their litter through immunomodulation from the gastrointestinal tract. Thus, the objective of this study was to evaluate the effect of the inclusion of β-glucans in the diet of replacement gilts during the adaptation, gestation and lactation phases on their response and the response of their litter to vaccines against Parvovirus and Leptospirosis, as well as its effect on parity performance and immune parameters of colostrum and milk. In two trials, gilts were randomly assigned to one of two treatments: with or without the inclusion of β-glucans at 300 g/ton in the basal diet. Gilts consumed the experimental diets during the adaptation period in the first experiment (EXP1) and from d 75 of gestation until d 10 of lactation in the second experiment (EXP2). Blood samples were collected from sows and from their piglets. In addition to blood collections, colostrum and milk were also collected in EXP2, and the reproductive performance of sows at the first farrowing was evaluated. Qualitative data were analyzed by chi-square, and quantitative data were evaluated using ANOVA or Kruskal-Wallis, according to their normality. There was an effect of treatment in EXP2 on the IgA and IgM concentrations and mitogenic activity in colostrum (P < 0.05), and for IgA in milk from sows (P < 0.05). For parvovirus and Leptospira spp. antibodies, in the two experiments, there was no difference between treatments (P > 0.05), as well as for reproductive parameters. Thus, under the experimental conditions of this study, it is possible to conclude that including 300 g/ton β -glucans in the diet of first-parity sows can increase the concentration of IgA in their colostrum and milk, as well as the proliferation of intestinal epithelial cells, while decreasing the concentration of IgM in their colostrum, but not in milk.