Essential oils of Ocimum gratissimum and Zingiber officinale as anesthetics for the South American catfish Pseudoplatystoma reticulatum

Abstract This study evaluated the essential oils of clove-basil (Ocimum gratissimum) and ginger (Zingiber officinale) as anesthetics for the South American catfish Pseudoplatystoma reticulatum and their effects on fish hematology and plasma glucose. For each essential oil, three concentrations were tested (100 mg L−1, 150 mg L−1 and 200 mg L−1) and a control lacking the essential oils was also present. Fish with a mean weight of 40.0 ± 9.9 g were used to provide for 6 replicates per treatment, each fish being a replicate. The times for induction and recovery, as well as the following hematological variables were assessed: Hemoglobin, hematocrit, total number of red blood cells (RBC), total number of white blood cells (WBC), total count of thrombocytes, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH) in addition to plasma glucose. Significant negative relationships (p