Effect of fibre and digestible energy levels on retail cuts, gut characteristics and morphology of growing rabbits

Abstract

The retail cuts, gut characteristics and morphology of rabbits fed with varying dietary fibre and digestible energy (DE) levels were measured in a 70-d feeding trial using 135 weaner rabbits. The experiment was designed as a 3 × 3 factorial arrangement of treatments having 3 levels of dietary fibre (low, optimum and high) and 3 levels of DE (low, optimum and high). The rabbits were allotted to 9 dietary groups consisting of 15 rabbits each. Main effect of fibre and DE showed that dressing out percentage (P < 0.05), chilled carcass weight (P < 0.05) and reference carcass weight (P < 0.01) increased with increasing inclusion levels of fibre. Rabbits fed with (430 – 456 g/kg NDF, 249 - 253 g/kg ADF) had the highest (P < 0.05) weights of thoracic cage, loins, hind part, small intestine, empty caecum and highest (P < 0.05) villus height in the duodenum and jejunum. Rabbits fed (10.5 – 11 MJ/kg) diets had the least (P < 0.05) chilled and reference carcass weight. Interaction effect of fibre and DE showed that rabbit fed (445.70g/kgNDF, 252.10g/kgADF and 8.01MJ/Kg) diet recorded the highest (P < 0.05) chilled carcass weight. Rabbit fed with low fibre (249 – 258 g/kg NDF, 149 - 157 g/kg ADF) diets not withstanding the level of DE had low (P < 0.05) chilled and reference carcass weight. The villus height of the duodenum and crypt depth of the jejunum increased (P < 0.05) with increasing level of dietary fibre irrespective of the level of digestible energy. In conclusion, feeding of (440.41 g/kg NDF, 250.09 g/kg ADF, 10.52MJ/kg) diets to rabbits favoured improved retail cuts, gut characteristics and gut morphology.