Ultrastructural changes in the digestive system ofIndoplanorbis exustus(Gastropoda: Planorbidae) exposed to the molluscicides, niclosamide andBrassaia actinophylla

The adult snails, Indoplanorbis exustus were exposed to the synthetic molluscicide, niclosamide, and the crude – aqueous extract of Brassaia actinophylla at the LC50 concentrations (0.009 mg/ 1 and 23.73 mg/1, respectively) for 24 hours. The results showed relatively similar ultrastructural changes in the digestive system of snails exposed to niclosamide and B. actinophylla. The general cytological alterations that occurred in the epithelia of esophagus, intestine and digestive gland were the formation of blebs, increased fusion of vacuoles, infolding and thickening of basal lamina, formation of myelin-like figures, degranulation and dilation of rough endoplasmic reticulum, swelling of mitochondria and cristae, and an increase in mucus production. Most of these reactions were more severe in snails treated with B. actinophylla than those exposed to niclosamide.