S.S. VUTUKURU, DEEVEKA ZAMARE, SNEHA MURALIDHARAN,KALPANA CHAWLA AND J. VENKATESWARA RAO
Abstract
Moringa oleifera (Moringaceae) seed powder contains polyelectrolytes which constitute activeingredients for water purification and is being employed as a bio-coagulant. Indiscriminate use of such materials to purify water can be toxic to various cultivable aquatic species. The present workassessed the lethal and sub-lethal effects of the aqueous suspension of M. oleifera seeds usingzebra fish model. Static bioassays were carried out on Danio rerio exposed to differentconcentrations of aqueous extract and the 96-h median lethal concentration (LC50) was found to be308 mgL-1 and 1/10th of this viz. 30.8 mgL-1 was considered as sub-lethal concentration. Toxicmanifestations such as hyper secretion of mucus, surfacing, darting movements, loss of balance,irregular swimming patterns were noticed in the fish exposed to lethal concentration. M. oleiferaseed extract was found to be toxic and induced mortality in fish from 24 h to 96 h, demonstratinga linear and positive correlation with both the concentration and duration of the exposure. Thepresent study also examined the toxic effects of seed powder suspension on vital biochemicalconstituents such as glycogen and total protein content in gill and muscle tissues of the fish.Significant decrease (p<0.05) was observed in glycogen and protein at the end of 96 h in gill andmuscle tissues both in lethal and sub-lethal exposures suggesting that aqueous extract of M.oleiferaseeds is moderately toxic even at low doses.