Antifouling activity of the methanolic extract of Syringodium isoetifolium, and its toxicity relative to tributyltin on the ovarian development of brown mussel Perna indica

The present study evaluated reproductive toxicity and antifouling activity of methanolic extract of seagrass Syringodium isoetifolium (25 μg/ml) relative to the conventional antifoulant, tributyltin (TBT; 100 ng/l) on the ovarian development of the brown mussel Perna indica. Gonado Somatic Index (GSI) and Digestive Gland Index (DGI) of TBT exposed mussels decreased in comparison with mussels exposed to S. isoetifolium extract. Interestingly, mussels treated with S. isoetifolium showed normal cellular architecture in gills, digestive gland, muscle and ovary. However, TBT increased interfilamental space and fusion of the filaments in gills, disruption in the digestive tubules and reduction in basement membrane thickness. Besides in adductor muscle, TBT induced muscle degeneration, and necrotic muscle layer. In ovary, TBT inflicted the fusion of developing oocytes. TBT had significantly retarded the ovarian development and substantially affected the biochemical constituents leading to an impairment of oogenesis as against the null effects noticed from the S. isoetifolium extract treated mussels. On the ground of eco-friendly properties, the seagrass S. isoetifolium could be used as a source for the production of green antifoulant.

highlights
► Toxicity studies comparing natural and chemical antifoulants are limited.
► Relative reproductive activity (GSI & HSI) was affected due to TBT treatment.
► Cellular level changes in test tissues of TBT exposed mussels were observed.
► Biochemical constituents of mussel were affected because of TBT exposure.
► Syringodium isoetifolium extract exhibited less toxicity than TBT in mussel.