Prospects of Leaf and Root Extracts of Drumstick Tree (Moringa oleifera) as Eco-friendly Organic Piscicide to Eradicate the Unpleasant Fishes from Culture Ponds

Abstract

This study investigates the piscicidal properties of the Moringa oleifera plant, focusing on its raw and dry leaf and root extracts, and their effects on the experimental fish species Heteropneustes fossilis (Bloch). Conducted under standard laboratory conditions, the experiment aimed to determine the lethal concentration (LC50) values of various extracts to evaluate toxicity levels. Extracts from Moringa oleifera were prepared using three different solvents: absolute ethyl alcohol, 50% ethyl alcohol, and distilled water. The toxicity of these extracts was assessed by determining the LC50 values, which indicate the concentration required to kill 50% of the test fish population. The absolute ethyl alcohol extract from dry leaves exhibited the highest toxicity, yielding the lowest LC50 value. The order of toxicity from the extracts was observed as follows: for the leaf extracts, absolute ethyl alcohol showed the highest toxicity, followed by 50% ethyl alcohol, and distilled water. In terms of root extracts, absolute ethyl alcohol again ranked highest in toxicity, followed by distilled water and then 50% ethyl alcohol. Histopathological examinations revealed significant alterations in the tissues of the fish exposed to these extracts. The gill tissue demonstrated notable damage, including detachment of the epithelial layer and injury to gill arches and filaments. The liver exhibited disorganized parenchymal structures, vacuole formation, and signs of hyperplasia. Additionally, the intestinal mucosa displayed ruptures, swelling in the muscularis layer, and small vacuoles in the sub-mucosa. The findings indicate that the absolute ethyl alcohol extract of Moringa oleifera leaves is more toxic than other forms, with noticeable detrimental effects on the gill, liver, and intestinal tissues of Heteropneustes fossilis. The toxic nature of these extracts was further corroborated through phytochemical analyses and behavioral observations of control fish. This study highlights the potential risks associated with the use of Moringa oleifera as a piscicide and underscores the need for caution in its application in aquatic environments. Further investigations are warranted to identify the specific toxic compounds responsible for these adverse effects and to understand their mechanisms of action.