Antifungal Efficacy of Lemongrass Essential Oil Against Aspergillus fumigatus Isolates from Poultry in Katsina State

Aspergillosis caused by Aspergillus fumigatus is a common respiratory disease in commercial poultry in northern Nigeria, particularly during the dry harmattan season when dusty conditions favour spore dissemination. In Katsina State, North West Nigeria, conventional antifungal drugs such as amphotericin B are expensive and often inaccessible on small-scale farms. Essential oils extracted from aromatic plants including lemongrass have demonstrated broad-spectrum antifungal activity in in vitro studies. This study evaluated the antifungal efficacy of Cymbopogon citratus essential oil against Aspergillus fumigatus isolates recovered from infected broiler chicks in Katsina. Fungal isolates were obtained from tracheal swabs and lung lesions of dead birds and identified by microscopy and cultural characteristics. Minimum inhibitory concentration of lemongrass essential oil was determined by broth microdilution according to the Clinical and Laboratory Standards Institute methodology. Amphotericin B served as the positive control. Lemongrass essential oil inhibited all 15 isolates tested, with minimum inhibitory concentration values ranging from 0.25 to 2.0 mg/mL. Amphotericin B MIC ranged from 0.5 to 4.0 micrograms/mL. Minimum fungicidal concentration for lemongrass oil was consistently one dilution above the MIC. Gas chromatography-mass spectrometry identified citral as the major constituent at 78.2 percent of the oil composition. These results suggest that lemongrass essential oil has promising antifungal activity against Aspergillus fumigatus and warrants further investigation as an affordable biosecurity tool for poultry farms in Katsina and similar arid-zone settings. Keywords: lemongrass, Aspergillus fumigatus, antifungal, poultry, Katsina.