Abstract
BACKGROUND AND AIM: The global ban on antibiotic growth promoters (AGPs) in poultry production has intensified the search for effective phytogenic alternatives. Curcuma xanthorrhiza Roxb., commonly known as Javanese turmeric, exhibits antimicrobial and antioxidant properties attributed to its bioactive compounds, including xanthorrhizol and curcumin. This study evaluated the potential of a novel adjuvant extract (adjuvant C. xanthorrhiza Roxb. [ACX]) derived from C. xanthorrhiza Roxb. to replace AGPs in broiler diets. This study aimed to assess the in vitro antimicrobial and antioxidant activities of ACX and determine its efficacy as a growth-promoting feed additive in broiler chickens relative to AGPs. MATERIALS AND METHODS: ACX was produced through double extraction of dried C. xanthorrhiza rhizomes and standardized for xanthorrhizol and curcuminoids using high-performance liquid chromatography. In vitro assays determined the minimum inhibitory concentration (MIC) and minimum fungicidal concentration against Escherichia coli and Aspergillus flavus, and antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl assay. A total of 420 Cobb CP707 broilers were allocated to seven dietary treatments, including a negative control, a virginiamycin-positive control, and five graded ACX concentrations (20-320 ppm). Growth performance, carcass traits, internal organ weights, digestive tract dimensions, and ileal microbiota were assessed over a 35-day feeding trial. RESULTS: ACX demonstrated antimicrobial activity (MIC = 80 μg/mL) and antioxidant potential (half-maximal inhibitory concentration = 57.3 μg/mL). Supplementing with 20 ppm ACX increased body weight by 7% and improved feed conversion ratio by 8% compared to control birds. Unlike AGPs, ACX supplementation did not increase feed intake, suggesting enhanced nutrient utilization. ACX also reduced abdominal fat and liver weight, with minimal impact on carcass yield or immune-related organs. Microbiota analysis revealed increased abundance of Firmicutes and decreased abundance of Proteobacteria in ACX- and AGP-fed groups, without disrupting microbial diversity. CONCLUSION: ACX supplementation at 20 ppm effectively enhanced broiler performance, reduced fat deposition, and modulated gut microbiota, offering a promising phytogenic alternative to AGPs. These findings support the integration of C. xanthorrhiza Roxb. extract into poultry nutrition strategies aimed at sustainable production.