Acute lethal toxicity of dried garlic (Allium sativum) powder on orange-spotted grouper (Epinephelus coioides) juveniles under static exposure

Abstract

The present study was carried out to assess the toxic effect and determine the lethal concentration of dried garlic (<em>Allium sativum</em>) powder on the orange-spotted grouper (<em>Epinephelus coioides</em>) juveniles. Laboratory static bioassays were conducted to determine the 96-h LC₅₀ of different concentrations of garlic (0, 30, 60, 90, 120, 150 and 180 mg L^-1) on grouper juveniles (mean weight, 35.4±6.18 g and mean length, 13.2±0.51 cm). The 96-h LC₅₀ was 74.78 mg L^-1 with lower and upper confidence limits of 62.8 and 89.06 mg L^-1, respectively. All fish exposed to 30 to 180 mg L^-1 exhibited rapid movement, faster opercular activity and erratic swimming whereas at higher concentrations (90 mg L^-1 to 180 mg L^-1) fish showed additional behavioral changes such as loss of balance, lethargy, gulping for air and respiratory distress. Water quality parameters were within the recommended acceptable limits. This LC₅₀ value can be used as a baseline reference to generate an effective concentration of garlic for future prophylaxis and treatment for parasitic, viral and bacterial infection in grouper.