Behavior Changes and LC50 of Dried Garlic (Allium sativum) Acute Toxicity in Nile Tilapia (Oreochromis niloticus) Juvenile [RESEARCH NOTE

Abstract

Plant-based compounds are emerging substitutes for chemical treatments in aquaculture since they are known to cause less harm to both the environment and its organisms. Garlic (Allium sativum) is a popular herb that has a broad range of uses, especially in the control and treatment of bacterial and parasitic diseases. However, its toxicity to tilapia is not well-studied. Hence, this study was conducted to test the toxicity levels of garlic powder in juvenile Nile tilapia (Oreochromis niloticus) by determining the cumulative mortality and median lethal concentration (LC50). Test fish were exposed through immersion in 6 concentrations (150, 200, 250, 300, 350, and 400 mg L-1) of garlic powder with 25% allicin and a control in 96 h static bioassay. Within 24 h, test fish exposed to 250 mg L-1 garlic and above, exhibited abnormal behaviors such as lethargy, gasping for air, and weak responses to environmental stimuli. Cumulative mortality was highest at 100% in 400 mg L-1 garlic at 48 h. Mortalities were dependent on the concentration and duration of exposure. The 96 h LC50 of garlic powder to O. niloticus was 225.86 mg L-1 with lower and upper confidence limits of 210.37 and 242.50 mg L-1, respectively at 27°C.