Abstract

In poultry production, the transition to antibiotic-free systems has resulted in an increased demand for effective natural growth promoters. The present study aimed to evaluate the effectiveness of a mash-form feed additive made from microwave-extracted ginger, turmeric, and teak leaf phytobiotics, combined with a multi-strain bacterium as a probiotic, administered at graded inclusion levels in broiler chickens. A 35-day feeding experiment was conducted with 300 broiler chickens, arranged in a completely randomized design with five dietary treatments and five replicates per treatment. In the first group, chickens received only the basal diet and served as the control (T0). The treatment groups received the basal feed top-dressed with the phytobiotic and probiotic additive at inclusion levels of 0.2% (T1), 0.4% (T2), 0.6% (T3), and 0.8% (T4). Measurements of performance, including body weight gain (BWG), feed conversion ratio (FCR), performance index, and income over feed cost (IOFC), were collected and analyzed. High-performance liquid chromatography confirmed the presence of key bioactive compounds, such as curcumin and 6-gingerol. The inclusion of 0.2% bacterium as a probiotic additive resulted in optimal BWG, FCR, and the highest IOFC, indicating that this level was biologically effective and economically efficient. In contrast, higher inclusion levels of bacteria as probiotics led to reduced performance, likely due to polyphenol-induced mineral binding and issues with feed palatability. The co-administration of probiotics may enhance the bioavailability of curcumin and promote a healthier gut environment. The present findings highlighted the potential of phytobiotic-probiotic combinations as alternatives to antibiotic growth promoters when used at optimal dose levels.