Biomorphometric and hematobiochemical alterations in the juvenile african catfish Clarias gariepinus exposed to propranolol.

Propranolol (PRO) is a beta-blocker drug used for the treatment of anxiety, chest pain, migraine and tremors. The present study investigated whether sublethal concentrations of PRO have effects on the body condition, biochemistry, and hematology of Clarias gariepinus juveniles. The 96-h median lethal concentration (LC₅₀) of the drug, which was established through an acute toxicity study, was 9.48 mg/L. Based on these values, the fish were exposed for 21 days to the control and sublethal concentrations of 1.90, 0.95, and 0.63 mg/L, which are equivalent to the 1/5th, 1/10th, and 1/20th of the LC₅₀ of PRO, respectively. After 21 days of exposure, the fish were removed from the toxicant and kept in toxicant-free water for 7 days to recover. The standard length and body weight of each fish were measured after each exposure period. The condition factor (CF) and hepatosomatic index (HSI) were not significantly affected by the drug. The red blood cell (RBC) count, hemoglobin (Hb) count and packed cell volume (PCV) decreased from day 7 to 21 at the tested concentrations, while the white blood cell (WBC) count significantly increased. There were alterations in the mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin (MCH) in the exposed groups compared to those in the control group. When neutrophil counts increased, the lymphocyte counts decreased, but the monocyte, basophil cell and eosinophil cell counts were not affected. Among the liver enzymes, only aspartate aminotransferase was significantly stimulated in the groups that were exposed to the drug. The protein and glucose levels of fish exposed to the drug decreased. Most of the studied parameters returned to their original values after the 7-day recovery period. The information provided in the current study will be helpful in the monitoring of PRO contamination in aquatic environments.