Effect of chicory products with different inulin content on rat caecum physiology

A 4-week experiment carried out on rats addressed the analysis of physiological properties of model casein diets supplemented with 5% cellulose or different preparations of chicory roots: flour, pulp, high- and low-molecular inulin (IN(HM) and IN(LM) respectively). Of all preparations, only pulp did not induce the hypertrophy of caecum walls or an increase in the bulk of caecal digesta. Chicory preparations lowered caecal pH and ammonia concentration (except IN(LM) preparation), evoked increased hydration of caecal digesta and protein content. The highest concentration of volatile fatty acids (VFA) was observed in rats fed a diet containing chicory pulp and IN(HM), whereas the lowest VFA concentration was reported after the administration of an IN(LM)-containing diet. The VFA pool was the highest in rats receiving a diet supplemented with chicory flour. All preparations examined diminished the coefficient of protein digestibility but not decrease nitrogen retention. The lowest levels of glucose and total cholesterol, at concurrently the highest level of HDL fraction, were recorded in serum of rats fed IN(LM). A distinct increase in intestinal wall and intestinal digesta, as well as the highest production of VFA and the lowest pH of caecal digesta indicate that chicory flour ingested to a semi-synthetic diet had the most profitable effect on the functioning of rat caecum, compared with other chicory products. Compared with the IN(HM), the preparation of IN(LM) increased caecal wall hypertrophy without increasing VFA production, still simultaneously increasing ammonia content and pH of caecal digesta, decreasing the total cholesterol concentration and increasing HDL content in serum.