engleski

Effect of levamisole on the number of intestinal goblet cells in weaned pigs experimentally vaccinated against colibacillosisms

Postweaning colibacillosis (PWC) is etiologically complex disease commonly induced by F4ac+ porcine enterotoxigenic (ETEC) Escherichia coli for which no effective vaccine is available. The objective of this study was to determine nonspecific immunomodulatory effect of levamisole in the combination with specific intragastric immunization of weaned pigs with a candidate F4ac+ non-ETEC oral vaccine on the population of the intestinal goblet cells (GC). Pigs were immunized with F4ac+ non-ETEC strain, in combination with or without levamisole. Seven days after that pigs were challenged with F4ac+ ETEC strain and 14 days following the immunization they were euthanatized for sampling of specimens of the small intestine for immunohistochemistry and morphometric analyses. Samples of the ileum were tested for the presence of acidic and neutral carbohydrates, components of mucus produced and secreted by the intestinal goblet cells (GC). The volume density (VV) of the PAS+ and AB+/PAS+ GC was determined using stereological point-counting method. The Vv of the ileal PAS+ GC was the lowest (0.130 ± ; 0.075 mm3) in the pigs that were immunized with vaccine candidate F4ac+ non-ETEC strain. Interestingly, AB+/PAS+ GC Vv were found to be the highest (0.262 ± ; 0.091 mm3) in this group of pigs. The Vv of PAS+ GC was the largest (0.201 ± ; 0.064 mm3) in negative control group of pigs. Pigs from levamisole pretreated group were shown to have the lowest Vv (0.166 ± ; 0.051 mm3) of AB+/PAS+ GC. According to presented data, there is no significant influence of non-specific/specific immunization on nonimmune defence mechanism of intestinal mucosa, as measured by GC Vv in weaned pigs. Hence, it is likely that the production of mucus was not affected and that nonspecific protection of porcine intestine provided by mucus layer was not compromised following peroral immunization against PWC. Also, presumably anti- inflammatory effect of levamisole was observed as the population of ileal mast cells was not considerably affected by non- specific/specific immunization and challenge infection.

goblet cells ; intestine ; specific/non-specific immunization ; colibacillosis ; pigs

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