Effects of Citrus Pulp and Wheat Bran on Chemical Composition, Fermentation Profile, and Ruminal Degradability of Sunflower Silage

Sunflower (Helianthus annuus L.) is an alternative forage for silage production in tropical systems; however, its high moisture content and limited fermentable carbohydrates may impair fermentation and nutrient preservation. This study evaluated the effects of citrus pulp (CP) and wheat bran (WB) on the chemical composition, fermentation characteristics, dry matter losses, and ruminal degradation of sunflower silage during 21, 42, 63, and 84 days of ensiling. Sunflower forage was ensiled with control (SG), 5% CP (SG + CP), or 5% WB (SG + WB). Ruminal degradation was evaluated using the in situ nylon bag technique with three rumen-cannulated Jersey steers. Citrus pulp increased DM potential degradability (76.30 vs. 70.02%; p < 0.001) and effective degradability (62.17 vs. 57.88%; p < 0.001), while reducing the indigestible fraction (23.69 vs. 29.97%; p < 0.001). For NDF, CP increased potential degradability (89.55 vs. 84.87%; p < 0.001) and reduced the indigestible fraction (10.44 vs. 15.12%; p < 0.001). Wheat bran increased the DM degradation rate (0.21%/h; p = 0.027) and N-NH3 accumulation. Ensiling duration affected DM degradation rate (p = 0.010) and effective degradability (p = 0.013), with the highest values at 42 days. Citrus pulp provided the most consistent improvements in ruminal utilization of sunflower silage.