Ascaridia galli infection of pullets and intestinal viscosity: consequences for nutrient retention and gut morphology

Abstract

1. Pullets were given a control diet or a diet supplemented with a non-starch-polysaccharide hydrolysing enzyme preparation (NSP-enzyme) from weeks 6 to 14 of age to induce differences in the viscosity of the small intestinal ingesta. Half of each feeding group (n = 25) was infected with 250 embryonated Ascaridia galli eggs at an age of 6 weeks. 2. At 14 weeks of age, before the pullets were slaughtered, a balance experiment was conducted, to sample ingesta for viscosity measurements. Also, tissue samples of jejunum and ileum were taken for morphometrical and histopathological studies. 3. An infection of pullets with A. galli reduced the viscosity of the jejunal ingesta at high initial levels of viscosity after feeding the NSP-enzyme unsupplemented diet. 4. The faecal A. galli egg output by the pullets expressed as eggs per g excrement (EpG) was significantly reduced in infected pullets given the NSP-enzyme supplemented diet. Also, the number and length of worms was less in these pullets. 5. The tunica muscularis of the jejunum was significantly thickened, this effect being more pronounced at a low intestinal viscosity. 6. NSP-enzyme addition resulted in an increased length of jejunal villus and was paralleled by a decrease in jejunal viscosity. 7. Histopathology of jejunal and ileal sections revealed no pathological alterations. 8. The apparent retention of organic matter was increased after enzyme addition while parasite infection exerted no effect.