Prevalence of Henneguya Chrysichthys and Its Infection Effect on Chrysichthys Nigrodigitatus Fecundity

Abstract

Four Hundred (400) samples of Chrysichthys nigrodigitatus were examined for Henneguya chrysichthys using methods described for gill examination, egg separation and histopathology. Monthly prevalence ranged from 5(14.7%) to 17(51.5%). Highest monthly parasite intensity (5 parasites /kg) was recorded in the month of June and July while highest mean condition factor (0.9900 kg/cm³) was observed in the month of July. 88 (22.0%) and 47 (11.8%) prevalence were recorded for wet and dry seasons respectively. More females (17.3 %) hand infection than males (16.5 %). Infection was highest in 41-50cm, 61cm-70cm and 61cm-70cm in the low moderate and high infection categories. Eighty (20.0%) of 238 (59.5 %) females examined were gravid. 57 (14.3%) of gravid females examined were infected. Absolute fecundity range of 3,865 eggs to 28,675 eggs and 3,601 eggs to 24,699 eggs and relative fecundity of 366 and 251 were recorded for uninfected and infected fish respectively. Oocyte diameter varied between 1.0mm and 3.6mm and 0.3mm and 1.8mm for uninfected and infected gravid females. Histological examination revealed distorted connective tissue elements, flaccid oocytes with some oocytes without nucleus in the ovarian tissue of infected gravid females. F=2.813 L ^2.3 and F=2.761 L ^2.1 were obtained for fecundity length relationship for uninfected and infected gravid female Chrysichthys. The results are discussed.

Keywords: Prevalence, Histopathology Fecundity, Gravid, Oocytes.