ANAESTHETIC EFFECTS OF NUTMEG (Myristica fragrans) on Clarias gariepinus FINGERLINGS

Abstract

This study was carried out to determine the anaesthetic effects of ethanolic extracts of nutmeg powder on C. gariepinus. 250 healthy fingerlings ( 25.20 ± 0.03g ) were exposed to five varying test concentrations (1ml/ L, 2ml/ L, 3ml/ L, 4ml/ L and 5ml/ L of ethanolic extract of M. fragrans under America standard bio-assays procedure. Indices such as water quality parameters (pH, Conductivity, Dissolved oxygen and conductivity), haematology parameters (PCV, Hb, RBC, WBC, MCV, MCH and MCHC), histology examinations (gills, liver and kidney), behavioural responses and LC 10 were observed and recorded. Data collected were subjected to Analysis of variance while the median lethal concentration was determined using Probit analysis. The effect of ethanolic extract of M. fragrans increased with increase in concentration; the induction time decreased while the recovery time increases. The experimental fish displayed rapid opercular movement, erratic swimming, hyperventilation and loss of reflex during exposure to ethanolic extract of M. fragrans at different time duration as concentration increased. The temperature, pH, Dissolved oxygen and conductivity in the experimental tanks showed no significant difference before induction but there was significant difference (P<0.05) after induction (introduction of extract). Blood parameters (PCV, Hb, RBC) showed a decreasing trend, WBC showed increasing trend while MCV, MCH and MCHC were sinusoidal across treatments. Histological examination of the gills showed normal gill architecture (1ml/ L – 3ml/ L) while slight alteration of normal gill rakers, inflammation and swelling of the lamellae were observed at 4ml/ L – 5ml/ L; kidney showed slight hyperplasia of Bowmans capsule (1ml/ L- 3ml/ L) while lymphocytic infiltration, vacuolation, inflammation and necrosis were observed at 4ml/ L – 5ml/ L; Liver showed normal architecture (1ml/ L – 3ml/ L) while inflammation, hemolysis and hepatocytes degeneration were observed at 4ml/ L – 5ml/L. LC 10 obtained after 72hrs was 6.50ml/ L. Mortality of the test fish at 1ml/ L- 4ml was 0% while at 5ml/ L was 10%. Thus, this study revealed 3ml/ L safe level as anaesthesia with total recovery potentials. Therefore, ethanolic extracts of M. fragrans is recommended as anaesthesia for fish during handling operations such as transportation, sorting, weighing, surgical operations and also during treatment for disease.