Para avaliar os efeitos do processamento de milho extrusado, 63 leitões hibridos comerciais, machos castrados e fêmeas, foram desmamados aos 21 dias de idade (7,18 + 1,0 kg). Distribuídos em bloco ao acaso com três tratamentos (milho moido em peneira 3,0 mm, milho moído em peneira 1,0 mm e milho extrusado moido em peneira 1,0mm) e sete repetições. O milho utilizado foi oriundo do mesmo lote. As dietas experimentais foram formuladas a base de milho e farelo de soja para conter 3400 kcal/kg de EM e 1,45 g/kg de lisina digestível para o periodo do experimento (21 aos 35 dias). O processamento do milho não influenciou (P>0,05) o peso final, ganho de peso diário (GPD) e consumo de ração diánio (CDR). No entanto, os animais que receberam milho extrusado apresentaram melhor (P0,05). Junto ao colón, foram quantificadas as Bactérias Totais e Enterobacteriaceae que não apresentaram diferença significativa (P>0,05) nas concentrações. No entanto, a presença de Lactobacillus spp tendeu (P=0,07) a ser inferior nos animais alimentados com milho extrusado, quando comparado com milho 3 mm. Dietas compostas por milho extrusado proporcionam aos leitões melhor saúde e morfometria intestinal, assim como melhor conversão alimentar. Palavras-chave: Extrusão. Milho. Epitélio intestinal. Conversão alimentar. Leitões.The study aimed at evaluating the effects of corn processing (grinding and extrusion) on performance and intestinal parameters in weaned pigs. To accomplish our goal, 63 piglets (21 days-old, 7.18 + 1.0 kg BW) were randomly allocated (7 pens/treatment, 3 pigs/pen) to one of the three treatments: coarse com, coarsely ground com (hammer mill 3.0 mm screen); fine corn, finely ground corn (hammer mill 1.0 mm screen); extruded corn, extruded corn and finely ground (hammer mill 1.0 mm screen). Corn used wasfrom the same corn batch. The experimental period lasted 14 days and pigs had free access to feed and water. Diets were formulated with similar ME (3400 kcal/kg) and SID Lys (14.5 2 /kg) as recommended by Rostagno et al. (2011). Data analyses were performed using the GLIMMIX procedure of SAS. Pigs fed fine and extruded corn diets had better FCR (P < 0.05) than coarse corn group. Corn processing did not influence other performance variables. Duodenum and jejunum villus height and villus height: crypt depth ratio of pigs fed extruded corn were higher (P < 0.05) than pigs fed fine corn diet, with no difference from coarse corn fed pigs. Crypt depth was not affected by com processing. Duodenum mRNA expression of zonula occludens-1 (P < 0.05) and ocludin-1 (P = 0.07; tendency) were greater in pigs fed extruded than fine corn diets, with no difference from coarse corn diet. Corn processing did not affect mRNA expression of tight junction protein in the jejunum. There was a tendency (P = 0.07) for lower Lactobacillus group quantification in the colon of pigs fed extruded corn diet, while there was no significant effect of the experimental treatment over total Bacteria and Enterobacteriaceae. In conclusion, piglets fed finely ground or extruded com diets had better FCR than coarse corn group. However, pigs fed extruded corn diets had improved gut morphology and tight junction expression, therefore, extruded com would be more suitable for weaned piglets. Keywords: Extrusion. Corn. Feed conversion. Intestinal epithelium. Piglets
