Chicory (Cichorium intybus L) As Fibre Source in Pig Diets Effects on Digestibility, Gut Microbiota and Performance

The aim of this thesis was to increase our understanding about chicory (forage and root) as fibre source for pigs, by studying the effects of diets with inclusion of chicory on digestibility, digestion site, performance, gut microbiota and environment. In total 62 pigs were used, including newly weaned and growing intact pigs and growing post valve t-caecum (PVTC)-cannulated pigs. The weaned pigs were fed cereal-based diets with inclusion of 40, 80 and 160 g/kg of either chicory or ribwort forage. The growing pigs were fed cereal-based diets with inclusion of 80 and 160 g/kg of chicory forage and/or root. The cannulated pigs were fed diets with similar nonstarch polysaccharides (NSP) content, comprising of a basal diet and four diets with one of four fibre sources, two pectin-rich (chicory forage and sugar beet pulp), and two arabinoxylan-rich (wheat bran and grass meal). The results showed that the total tract digestibility of organic matter (OM) and energy of chicory forage was similar to commonly used forage crops. The total tract digestibility of NSP in both chicory forage and root was higher than the NSP digestibility in cereals. Inclusion of 80 g chicory forage/kg did not reduce the digestibility of OM, crude protein and energy. Inclusion of 160 g chicory forage/kg did not reduce growth performance and did not increase gastrointestinal organ weights. Chicory forage and root affected the gut microbiota differently with higher lactobacilli:coliform ratio when combined in the diet which indicates a synergistic effect. Chicory forage increased the abundance of Bacteroides-PrevotellaPorphyromonas in faeces. Increased total amount of fermentable dietary fibre in the diet increased the abundance of the same groups in ileal digesta. The effects of different fibre sources on the microbiota were to a high degree ingredient-specific. The effect on organic acids was NSP-structure specific with increased butyric acid concentration on arabinoxylan-rich diets. The effect of pectinrich diets was dependent on the intra-molecular structure of pectin, with highest proportion of acetic acid on chicory forage diet. In conclusion, these studies shows that there is potential for both chicory forage and root to be used as regular feed ingredients in pig diets.