Effect of the high fibre (8%) layer diets on digestive tract integrity

Although fibre is regarded by many nutritionists as a mere diluent of poultry diets, new experimental evidences suggest that the dietary fibre positively influences the digestive tract integrity. A 5-week feeding trial was conducted on 200 Tetra layers (28 weeks) assigned to 5 groups, housed in an experimental hall under controlled environmental conditions (temperature: 23.81±1.54°C; humidity: 64.76±11.93%), and 16h/24h light regimen. The control group (C) received a conventional diet (2780 kcal/kg metabolizable energy; 17.5% crude protein; 4.39% crude fibre). Compared to C formulation, E1 formulation included 23% sunflower meal, which increased the dietary fibre (8%). The other 3 experimental diet formulations differed from E1 formulation by the presence of phytoadditives or cellulolytic enzymes: E2 (0.015% enzyme); E3 (0.015% phytoadditive) and E4 (0.015% enzyme+0.015% phytoadditive). At the end of the experiment 30 hens were sacrificed (6 hens/group) to obtain jejunum samples for histological parameters. The results of the intestinal measurements revealed significantly (P≤0.05) lower values for experimental groups compared to C group. The lowest values registered for E1 group: villus height (583±99.74µm) and crypt depth (126±36.19µm). Mucosa thickness increased significantly (P≤0.05) in E3 group (275±70 µm) compared to C group (173±66.08 µm)