Palabras clave: Intestino delgado, MAPK, productos proinflamatorios, transporte intestinal. Abstract. With the abrupt weaning mortality of lactobacillus is induced and E. coli population is increased, which release proinflammatory products from their wall cell such as lipopolysaccharide (LPS). LPS activates a coordinated series of signs that involve the MAPK family, initiating a cascade of reactions that interrupt nutrient transport processes and can progress to multiple organic failure. The aim of this study was to determine the effect of adding ex vivo different levels of lipopolysaccharide of E. coli on lysine absorption in weaned pigs. The experiment was carried out with 16 weaned pigs 21 days old. Animals were fed during 10 days with a basal diet with milk and some of its derivatives. Pigs were sequentially slaughtered on days one, five, seven, and 10 after weaning, and jejunum extraction was realized to which the following substances were added: Lysine 0.91 mg mL -1 , LPS from E. coli (0.3 µg) and two MAPK pathway inhibitor (a) 203580 (10, 20 y 50 mM) (b) U-0126 (10, 20 y 50 mM). The addition of either 20 mm MAPK inhibitors significantly increased the uptake of lysine (P<0.01). Animals with 10 days post-weaning showed the highest percentage of absorption (P<0.01). As conclusion the lipopolysaccharides of E. coli contribute to the disruption of intestinal transport mechanisms of lysine.