Two probiotics were evaluated for their impact on neutral detergent fiber (NDF) and acid detergent fiber (ADF) as well as in vitro dry matter disappearance (DMD) of palm kernel cake (PKC), as a source of dietary protein and/or energy for ruminants. The treatments were four different rations: CS (control), PS (PKC as source of energy), P (PKC as source of energy and protein), and PC; two commercial probiotics formulas (ZAD and ICEC-Trol) were applied with four applications (control: without probiotic, Z: ZAD, ZI: combination of ZAD + ICEC-Trol, and I: ICEC-Trol). Using Cornell Net Carbohydrate and Protein System (CNCPS) v6.5, the experimental diets’ chemical analysis and fermentability were assessed. Adding the ZAD + ICEC and ICEC was improved (P < 0.05) DM disappearance (15%), NDF digestibility (14%), and ADF digestibility (26%). Using the CNCPS indicated that PS, P, and PC rations were higher in NDF than CS ration by about 28%, and CS and PC rations were higher in NSC, NFC, and total carbohydrate (CHO) by 34, 33, and 9% respectively more than PS and P rations. CS and PC rations occurred improvement in fermentability in organic matter, total carbohydrate, and starch by 19.5, 18.5, and 16.5%, respectively. In conclusion, using probiotics with PKC resulted in a greater elimination of dry matter disappearance and improved NDF and ADF degradation, and feeding ruminants palm kernel cake as a source of protein or energy and supplementing their diets with probiotics.
