In Vitro Pre-Cecal Digestion and Cecal Degradation of Pea Hulls, Artichoke Bracts, Date Flesh, and Date Pits for Rabbit Nutrition

Rising feed costs and the need for more sustainable livestock production have increased interest in co-products as alternative feed resources for rabbits. However, their nutritional value may be underestimated when evaluated only through pre-cecal enzymatic digestion, without considering cecal degradation. This study comparatively characterized pea hulls, artichoke bracts, date flesh, and date pits (three independent sources each, n = 3) and evaluated their nutritional potential using a sequential in vitro procedure combining pre-cecal enzymatic digestion with cecal degradation. Date flesh, characterized by high non-fibrous carbohydrate and low fiber, showed the highest pre-cecal enzymatic dry matter and organic matter digestibility (89.44% and 89.58%, respectively), with minimal additional contribution from cecal degradation. Pea hulls contained the highest crude protein (24.97% of dry matter) and showed high additional degradation of structural carbohydrates during the cecal phase, reaching cumulative neutral detergent fiber and acid detergent fiber digestibility (47.18% and 41.90%, respectively). Artichoke bracts showed moderate pre-cecal enzymatic digestibility and substantial additional utilization during cecal degradation. Date pits had the highest fiber, lignin, and tannin concentrations and the lowest pre-cecal enzymatic digestibility, although cecal degradation partially improved their nutrient utilization. Overall, these in vitro results suggest that cecal degradation can contribute substantially to the digestibility of residual structural carbohydrates in fiber co-products.