EVALUATION OF PLANT EXTRACTS FROM BANANA LEAVES AGAINST AEROMONAS HYDROPHILA INFECTION IN NILE TILAPIA (Oreochromis niloticus)

Abstract

This study investigated the pathogenic effects of Aeromonas hydrophila on Nile tilapia (Oreochromis niloticus) fingerlings under controlled experimental conditions at the University Fish Farm, Federal University Dutsin-Ma, Katsina State, Nigeria. Sixty tilapia fingerlings were sourced from Armana Fish Farm and acclimatized for two weeks in polythene tanks, receiving commercial Coppens feed (42% crude protein) twice daily. Fish were randomly assigned into four groups: uninfected control (UNC), infected positive control (IPC), infected-treated with basal diet (ITB), and infected-treated with extract-incorporated diet (ITC). The infection protocol involved intraperitoneal injection of A. hydrophila at a dose of 1×107 CFU/mL, determined through LD50 testing, which established 10^5 CFU/mL as the lethal dose for 50% mortality. Growth performance and survival parameters revealed significant differences among groups. The IPC group recorded the highest final body weight (40.54 ± 0.31 g) but exhibited the lowest survival rate (30.00 ± 0.00%) and highest mortality (70.00 ± 0.00%), reflecting survivorship bias. Feed conversion ratio (FCR) and specific growth rate (SGR) did not differ significantly across treatments. Haematological indices showed limited variation, with only packed cell volume (PCV) differing significantly; ITC recorded lower PCV (17.00 ± 0.21%) compared to ITB (19.00 ± 0.18%). White blood cell count, haemoglobin concentration, red blood cell count, and bacterial load count exhibited non-significant differences, though numerical trends were observed. These findings highlight the complex interaction between infection pressure, survival rate, and dietary intervention, suggesting that while growth metrics may appear enhanced under infection, survival outcomes provide a more reliable measure of treatment efficacy.