Feeding high fibre diets changes luminal environment and morphology in the intestine of sows ☆ A. Serena ⁎ , M.S. Hedemann, K.E. Bach Knudsen Department of Animal Health, Welfare and Nutrition, Danish Institute of Agricultural Sciences, Research Centre Foulum, DK-8830 Tjele, Denmark Abstract Sows were fed three diets varying in type and level of dietary fibre (DF). The low fibre diet (LF; 17% DF) was based on wheat and barley. In the two high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF; ∼ 44% DF), the cereal part of the diet was substituted with different co-products (sugar beet pulp, potato pulp, pectin residue, pea hull, brewer's spent grain, and seed residue). The diets were fed for a four-week period to 12 sows (4 for each diet). Sows were stunned 4 h post-feeding, and digesta and tissue samples were collected from various parts of the small and large intestines. The carbohydrate load to the large intestine was 538–539 g/d when feeding the high DF diets and 190 g/d when feeding diet LF. Feeding sows the high DF diet containing large proportion of soluble DF resulted in a lower dry matter content of digesta (23 contra 28%), a higher tissue weight (2.9 contra 2.0 kg), and a higher crypt depth (492 contra 330 μm) and area (23,201 contra 15,751 μm 2 ) in the colon compared with the low DF diet. In conclusion, increasing the amount of DF in the diet for sows resulted in an increased amount of digesta entering the large intestine which influences the functional properties of digesta. Furthermore, a high DF diet with a high proportion of soluble DF increases tissue weight, crypt depth and crypt area in the midcolon compared to a low fibre diet. © 2007 Elsevier B.V. All rights reserved. Keywords: Co-products; Carbohydrates; Luminal environment; Morphology; Sows 1. Introduction Although sows have a high potential capacity to ferment dietary fibre (DF; non-starch polysaccharides + lignin) (Bach Knudsen and Jørgensen, 2001), they are usually fed concentrate diets. Increased DF levels have consequences for the site of digestion as a smaller proportion of carbohydrates in the form of starch is enzymatically digested in the small intestine, while larger proportions as non-starch polysaccharides (NSP) are fermented by bacteria in the large intestine to produce short-chain fatty acids. Among the co-products characterized, pea hull, seed residues, brewer's spent grain and pectin residue are all characterized by a relatively high content of insoluble DF, whereas sugar beet pulp and potato pulp are characterized by a high content of soluble DF. Consequently, these co-products have different physi- cochemical properties, which may have different physicochemical properties in the gastrointestinal tract and therefore influence the digestibility characteristics. The aim of the present investigation was to study the influence of type and level of DF on the luminal environment and morphology in the gastrointestinal Livestock Science 109 (2007) 115 – 117 www.elsevier.com/locate/livsci ☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. Tel.: +45 98991136; fax: +45 89991378. E-mail address: anja.serena@agrsci.dk (A. Serena). 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.105