Effect of dietary high- and low-methylated citrus pectin on the activity of the ileal microflora and morphology of the small intestinal wall of broiler chicks

1. A study was conducted with broiler chicks to evaluate the effects of die tary high-methylated citrus pectin (HMC) or low-methylated citrus pectin (L MC) on the performance, nutrient digestibility, morphology of the small int estinal wall and ileal microbial activity. 2. Both pectin products were tested at a dietary content of 30 g/kg using a diet based on maize and soya flour. 3. Inclusion of HMC in the diet depressed weight gain and food utilization significantly With a dietary addition of LMC there were only small decrease s in weight gain and food utilisation. 4. Digestibility of dry matter, organic matter, crude fat, starch and amino acids, nitrogen retention and metabolisable energy value were reduced sign ificantly when HMC was added to the diet. The addition of LMC to the diet r educed fat and ash digestibility and metabolisable energy value significant ly. 5. Inclusion of LMC in the diet increased ileal viscosity marginally, whils t HMC had such an effect that the supernatant could not be extracted. Micro bial activity in the ileum, particularly that of Enterococci, Bacteroidacea e, Clostridia and E. coli, was increased significantly with dietary additio n of HMC. Inclusion of LMC in the diet did not greatly affect microbial act ivity as only the number of Clostridia was increased. 6. The addition of HMC to the diet markedly affected the morphology of the intestinal wall and significantly increased the number of goblet cells per 100 villus cells and the sucrase isomaltase activity was increased signific antly. However, the morphology of the intestinal wall was hardly affected b y LMC, whereas the number of goblet cells per 100 villi cells was significa ntly increased. 7. Results of the present study indicate that the inclusion of water-solubl e pectins in diets of chicks changes ileal microbial activity and the morph ology of the small intestinal wall. The magnitude of these changes depends on the degree of methylation of the pectins.