Abbreviations: ADFI, average daily feed intake; ADG, average daily gain; BC, pigs weaned from basal-fed sows and unchallenged; BE, pigs weaned from basal-fed sows and enterotoxigenic Escherichia coli K88-challenged on days 9 and 10 post-weaning; BW, body weight; cDNA, complementary DNA; CD, crypt depth; EAST1, enteroaggregative Escherichia coli heat-stable enterotoxin 1; ETEC, enterotoxigenic Escherichia coli; G:F, gain:feed ratio; GCN, gene copy number; GI, gastrointestinal; IFN-γ, interferon-γ; LT, heat-labile enterotoxin; qPCR, quantitative real-time PCR; PW, post-weaning; SAS, Statistical Analysis System; SC, pigs weaned from seaweed extract-supplemented sows and unchallenged; SE, pigs weaned from seaweed extract-supplemented sows and enterotoxigenic Escherichia coli K88-challenged on days 9 and 10 PW; STb, heat-stabile enterotoxin b; SWE, seaweed extracts; TGF-β1, transforming growth factor-β1; VH, villus height