Control of Ichthyophthirius multifiliis Infecting African Sharptooth Catfish Clarias gariepinus Using Ocimum gratissimum

Abstract

Ichthyophthiriasis, caused by ciliate protozoa, Ichthyophthirius multifiliis, persists in freshwater fish and affects aquaculture production globally.An experiential study on Clarias gariepinus to investigate the potential of graded concentrations of ethanol leaf extract of O. gratissimum (ELEOG) for control of I. multifiliis (Ich) in a 96 h short bath treatment.A total of 120 ich-infected catfish, Clarias gariepinus were infected with 10,875 theronts and were randomly distributed in triplicates into five groups (A-E).Groups A, B and C (500mg/L chloramphenicol) served as the normal, negative control, and positive control, while groups D and E were treated with 500mg/L and 1,500mg/L ELEOG, respectively.ELEOG controlled the parasitaemia after the seventh-day post-inoculation but persisted after treatment relative to the standard drug, chloramphenicol's significant (P=0.05)performance.However, between 72 h and 96 h post-treatment, both the intensity of theronts and trophonts declined to a non-detectable level at a concentration of 500mg/L ELEOG with linear similarity with the standard drug.A positive and strong relationship was observed between pH and Ich intensity, although no Ich was detected at 5.5.There was no relationship between the temperature (25° C and 29° C) and Ich intensity.O. gratissimum is a good anti-ich plant material favouring 500mg/l and 1500mg/L ELEOG in bath treatment against I. multifilis.