Soluble fibre, starch and protein level in diets for growing rabbits: Effects on digestive efficiency and productive traits

Abstract From 29 d of age until slaughter (78 d), 246 hybrid rabbits were divided into six experimental groups and fed six diets ad libitum according to a bi-factorial arrangement with two soluble fibre-to-starch ratios (0.5 and 1.1), obtained by replacing starch (from 178 to 130 g/kg) with soluble fibre (from 84 to 141 g/kg), and three levels of crude protein (139, 154, and 172 g/kg diet). Growth traits were recorded on all rabbits; total tract apparent digestibility coefficients (CCTAD) were measured on 72 rabbits. Gut traits were obtained from further 36 rabbits slaughtered at 38 d of age. The increase in the soluble fibre-to-starch ratio increased (P