Enzymatic and fecundity evaluation of Fasciola hepatica exposed to different doses of γ- irradiation in Ethiopian sheep

Abstract

The upshot of γ-irradiated Fasciola hepatica infection on the activity of plasma glutamate dehydrogenase (GLDH) and γ-glutamyl  transpeptidase (GGT) was evaluated in 36 sheep infected with a single dose of 30, 60, 120, and 240 grays and those kept as negative and positive control over 17 weeks. During this period, serum and faecal samples, as well as body weight gains, were taken at weekly intervals. Furthermore, the effects of the irradiation dose (500) for oral vaccination and on the recovery of adult flukes were assessed following primary infection. Eggs were first detected in the faeces of infected sheep on week 8 post-infection. The parasite viability was severely  affected by doses of γ-irradiation of 120 Gy or 240 Gy. In the aforementioned doses, relatively low numbers of mature flukes of about 60 (17.1%) and 38 (10.8%) were recovered than the control group, respectively. The sensitized lambs also showed less hepatic damage  compared with the controls as indicated by lower levels of the serum enzyme glutamate dehydrogenase and γ- glutamyl transferase  significant body weight loss was observed between weeks 6 and 8 post-infection followed by a steady increase of the mean weight of  infected animals across time. In conclusion, vaccination of sheep with γ irradiated metacercariae of F. hepatica appeared to affect the number and development of the fluke population resulting in reduced hepatic damage during migration, reduced fecundity after patency, as measured by worm and egg counts, levels of serum glutamate dehydrogenase and γ- glutamyl transferase.