In this review, the methods to measure fibre and soluble fibre fractions have been briefly presented; we have referred to soluble fibre as the difference between Total Dietary Fibre (TDF) and Neutral Detergent Fibre (NDF) due to its simplicity to be obtained and the numerous studies that measured it; the effects of soluble fibre on performance, digestive efficiency and physiology, caecal activity and health of growing rabbits have been reviewed by a meta-analysis of studies available in literature, also with the aim of elucidating the relationships with other dietary nutrients. The level of soluble fibre affects the digestive utilizations of soluble and insoluble fibre fractions at ileum and caecum, ileal and caecal microbiota and caecal fermentations by modifying the amount and the type of substrate reaching the caecum. The increase of soluble fibre has a positive effect on the reduction of mortality in growing rabbits affected by epizootic rabbit enteropathy, which could be related to the high fermentability of soluble fibre, the changes exerted in the intestinal microbiota, and an enhanced gut barrier function just after weaning. A minimal supply around 12% of soluble fibre (as fed) is recommended in diets for postweaning and growing rabbits containing about 30% NDF and 18% ADF. These conclusions are linked to the use of sugar beet pulp as primary source of soluble fibre and should be confirmed with other soluble fibre sources
