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

الملخص EN

This study evaluated the effect of temperature, molluscicides (Co-pper sulphate and Niclosamide), fertilizers (Superphosphate and Am-monium sulphate) on the hatchability of Fasciola gigantica eggs.

The results showed that hatchability decreased to 4 % when eggs were in-cubated in bile secretion at 37ºC for 5 days and to 1.4 % for 10 days, but few eggs incubated in water at 37ºC hatched.

Bile secretion at 37ºC was a poor medium for in-vitro egg preservation.

But, hatching occurred only when eggs were transferred to water at 26ºC.

Tempera-true fluctuation from 26-4ºC or from 32- 4ºC 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 LC90 of Copper sulphate and Niclosamide against Biom-phalaria alexandrina and Lymnaea natalenesis had no toxic effect on Fasciola eggs.

The higher concentrations of Copper sulphate (30ppm) and Niclosamide (1ppm) slightly lower eggs hatchability rate than co-ntrols.

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 de-velopment, which increased by increasing Superphosphate concentration or with the prolongation of the exposure time.