Effects of haloperidol on peripheral erythrocytes and brain neurotransmitter levels of juvenile African Sharptooth Catfish Clarias gariepinus.

OBJECTIVE: The study investigated the effects of haloperidol on peripheral erythrocytes and brain neurotransmitter levels of juvenile African Sharptooth Catfish Clarias gariepinus. METHODS: Juveniles were exposed to different concentrations of haloperidol (0.12, 0.24, and 0.48 mg/L) for 15 days and subsequently withdrawn from the drug for 5 days. Blood samples from the fish on days 1, 5, 10, and 15 and after the 5-day withdrawal period were analyzed for mutagenic changes, after which the fish were sacrificed. The brain was sampled for serotonergic and dopaminergic analyses. RESULT: There was formation of micronuclei in the peripheral fish blood, which increased as the duration and concentrations of the drug increased. The drug significantly reduced the serotonin activity but increased dopamine activity. Some of the studied parameters, however, recovered from the effects of the drug after the 5-day withdrawal period. CONCLUSION: Haloperidol is toxic to fish, and its use in the environment should be guarded to avoid adverse impacts on nontarget species like fish.

Mutagenic and physiological responses in the juveniles of African catfish, Clarias gariepinus (Burchell 1822) following short term exposure to praziquantel.

Praziquantel (PZQ) is an acylated quinoline-pyrazine originally developed for veterinary application but now one of the most used anti-helminthic drugs for treatment of certain trematodes and cestodes in both human and other animals. The present study investigated the mutagenic and physiological responses in the juveniles of African catfish, Clarias gariepinus following short term exposure to praziquantel. Based on the 53.52 mg/l 96 h LC50 of PZQ obtained, two sublethal concentrations of 5.35 and 10.70 mg/l of the drug were selected and fish were exposed to these concentrations and control for 15 days. Micronuclei induction in the peripheral blood of PZQ-exposed fish was highest on day 10 but the fish morphological parameters were not affected. The packed cell volume (PCV) was significantly reduced (p<0.05) from day 5 while red blood cells (RBC) and hemoglobin (Hb) significantly declined (p<0.05) on day 15. Macrocytic anemia was observed on day 1 of study and thereafter microcytic anemia developed on day 5 of study. The white blood cell (WBC) was significantly (p<0.05) elevated from day 10 of exposure while values of mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC) were not significantly different (p>0.05) from the control. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glucose levels significantly increased while protein reduced (p<0.05) throughout the exposure period but a mixed trend was observed in the leukocyte differentials. PZQ should be used with caution as sublethal exposure elicited micronucleus induction and alterations of hematological and biochemical parameters in the fish.