Assessment of Pletekan Leaf Extract (Ruellia tuberosa L.) as an Antibacterial Feed Additive for Broiler Chickens (Gallus gallus domesticus L.) Infected with Salmonella sp.

The use of synthetic antibiotics as antibiotic growth promoters (AGPs) in broiler chickens raises concerns over antibiotic residues and bacterial resistance, necessitating safer natural alternatives. Ruellia tuberosa L. contains various secondary metabolites with potential antibacterial properties; however, its in vivo efficacy against Salmonella sp. remains poorly documented. This study aimed to analyze the phytochemical composition of R. tuberosa leaf extract and evaluate its antibacterial activity against Salmonella sp. in broiler chickens. A Completely Randomized Design (CRD) was employed with eight treatments: a positive control (tetracycline), a negative control (Tween-80), and six extract concentrations (125, 250, 375, 500, 625, and 1000 ppm), each replicated four times. Salmonella sp. counts in feces were assessed using the Most Probable Number (MPN) method with three serial dilutions (10⁻¹, 10⁻2, and 10⁻³), followed by confirmatory testing. The highest mean Salmonella sp. count was at 125 ppm (1.1775 MPN/g) and the lowest in the negative control (0.3 MPN/g). It was concluded that R. tuberosa leaf extract at 125-1000 ppm was not effective as an antibacterial agent against Salmonella sp. in broiler chickens in vivo.