ABSTRACT. Composition of glycoconjugates was examined in small intestines naturally infected with Isospora suis in preweaned pigs by use of 21 biotinylated-labeled lectins with avidin-biotin-peroxidase complex method. As compared with control pig, staining of 18 lectins altered in jejunal villus brush border and goblet cells of pigs naturally infected with I. suis. These results indicate that I. suis infection alters carbohydrate residues on the jejunal intestines.

ABSTRACT. Lectin staining pattern in Peyer's patches of porcine ileum was studied using twenty one biotinylated-labeled lectins as cell markers which were visualized with avidin-biotin-peroxidase complex method (ABC). WGA appears to be a selective marker for tingible body macrophages in the porcine germinal centers. ConA may be a positive marker for the lymphoid tissues, whereas 9 lectins (DBA, SBA, SJA, s-WGA, PNA, ECL, UEA-I, PHA-E, and PHA-L) may be negative markers for the lymphoid tissues in all areas. KEY WORDS: histochemistry, lectin, Peyer's patch.

ABSTRACT. Composition of glycoconjugates were investigated in Escherichia coli 09:K103:NM, 987P+ ST + -infected lower small intestines of 1-week-old pigs by the use of twenty one biotinylated-labelled lectins with avidin-biotin-peroxidase complex method. Piglets with experimental group were inoculated by feeding 5 ml of culture inoculum (5 × 10 9 colony-forming units/ml) with 15 ml of milk replacer. At the onset of diarrhea, experimental piglets and time-matched control piglets were euthanatized using electrocution, necropsied, and tested by lectin histochemistry. As compared with control, staining intensity of seven lectins altered in ileal villus brush border and goblet cells of pigs inoculated with the pathogen.-KEY WORDS: Escherichia coli, histochemistry, lectin.Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea and death in preweaned pigs. The organism has 2 types of virulence factors: fimbrial adhesions and enterotoxins. Of these fimbrial adhesions, 987P is the predominant adherence factor in piglets up to 2 weeks old [9]. Age resistant to 987P is well-understood and piglets older than three weeks appear to be resistant to infection with the strains of E. coli that express the 987P fimbriae [8]. ETEC possess fimbriae that bind to receptors on the brush border of intestinal epithelial cells. These receptors are carbohydrate moieties (often D-galactose, Nacetylglucosamine, N-acetylgalactosamine or Nacetylneuraminic acid) of glycoproteins, glycolipids, proteoglycans or mucins [4,7].Lectin was used to investigate interaction between 987P and the receptors in the intestinal surface [3,4]. Glycoconjugates of intestinal mucins prevent attachment of pathogenic bacteria by modulating their adherence to the intestinal enterocytes [10]. However, little is known about the glycoconjugate composition of intestines in response to E. coli infection.The objective of the present study was to examine whether the alteration of glycoconjugate in lower small intestine with E. coli bearing 987P infection with lectin histochemistry. To determine the specific changes in intestinal glycoconjugates, the lectin-binding capacity to 21 different sugars residues was investigated in the ileum of the pigs experimentally inoculated with the pathogen.Porcine enterotoxigenic E. coli 09:K103:NM, 987P + ST + were used in this study [12]. E. coli 09:K103:NM were tested for 987P fimbriae by slide agglutination with anti-987P serum before use [13]. Thirty two 1-week-old Large White-Landrace crossbred piglets purchased from a commercial swine farm were randomly assigned to experimental and control group. Each group consisted of 16, 1-week-old conventional piglet, respectively. Piglets with experimental group were inoculated by feeding 5 ml of culture inoculum (5 × 10 9 colony-forming units/ml) with 15 ml of milk replacer. Piglets with control group were administered 15 ml of milk replacer only. Piglets were examined 3 times per day post-inoculation (PI) for clinical signs.The experimental piglets and time-matched control piglets ...