The study aimed to determine the effect of probiotics derived from Kumpai Minyak grass silage isolates on the chemical characteristics, microbiology, and mineral composition through the feces of pegagan ducks. The study was conducted for sixteen weeks. The samples used were four hundred five-month-old female gotu kola ducks. The treatments given were untreated ration (Con) and basic ration supplemented with 0.2% (P2), 0.4% (P4), 0.6% (P6), and 0.8% (P8) probiotic silage of Kumpai Minyak grass. The observed variables were chemical characteristics (Moisture, pH, NH3, NO3, NO2), Microbiology (Lactic acid bacteria and Escherichia Coli colonies), and Mineral Composition (Ca, P, K, Mg and Zn). The results showed that treatment P8 was the best treatment, and had a significant effect on all parameters observed compared to other treatments. However, the P2, P4 and P6 treatments showed insignificant effects compared to Con. The high value of probiotic treatment is due to its ability to inhibit pathogenic bacteria and optimize the digestive tract, thereby increasing the digestibility and absorption of feed nutrients.

Index Terms- Probiotic, fecal, pegagan ducks, silage.