Efficacy of temperature, and two commonly used molluscicides and fertilizers on fasciola gigantica eggs

ABSTRACT

This study .evaluated the effect of temperature, molluscicides [Copper sulphate and Niclosamide], fertilizers [Superphosphate and Ammonium sulphate] on the hatchability of Fasciola gigantica eggs. The results showed that hatchability decreased to 4% when eggs were incubated in bile secretion at 37°C for 5 days and to 1.4% for 10 days, but few eggs incubated in water at 37°C hatched. Bile secretion at 37°C was a poor medium for in-vitro egg preservation. But, hatching occurred only when eggs were transferred to water at 26°C. Temperature fluctuation from 26-4°C or from 32- 4°C had an inhibitory effect on embryos development [35.2% and 32.3%, respectively] as compared to controls [60% and 63.9%, respectively]. The incubation period [19 and 17 days] was higher than controls [14 and 12 days, respectively]. The LC50 and LC9o of Copper sulphate and Niclosamide against Biomphalaria alexandrina and Lymnaea natalenesis had no toxic effect on Fasciola eggs. The higher concentrations of Copper sulphate [30ppm] and Niclosamide [Ippm] slightly lower eggs hatchability rate than controls. The rate decreased by increasing the exposure time from 3 to 6 hours with both molluscicides. Ammonium sulphate had a lethal effect on eggs, but Superphosphate had some inhibitory effect on egg development, which increased by increasing Superphosphate concentration or with the prolongation of the exposure time