Toxicological Evaluation of Ethanol Extract of Adenium obesum Stem Bark in African Catfish, <i>Clarias gariepinus</i>

Abstract

ABSTRACT:The toxicity of ethanol extract of Adenium obesum stem bark as a tool for aquaculture pond management prior to the stocking of desired fish species was evaluated in Clarias gariepinus over a 96-h exposure. The fish were exposed to 6.25 mgL -1 , 7.50 mgL -1 , 8.20 mgL -1 , 8.80 mgL -1 and 10.00 mgL -1 of the extract and a control in an acute static toxicity bioassay after performing a range finding test to determine the median lethal concentration (LC 50 ) of the extract. Exposed fish showed signs of changed behaviours with adaptive responses, respiratory distress and nervous compromise, including mortality in some of the exposed fish. The appearance and intensities of the observed signs were concentration and exposure period-dependent. An LC 50 value of 7.35 mgL -1 was established for the extract in the exposed fish where mean mortality was significantly (p<0.05) concentration and exposure period-dependent. The toxic nature of the extract in the exposed hardy fish can be exploited for effective aquaculture pond management against some unwanted predatory and weed aquatic organisms. However, the indiscriminate use of higher extract concentrations could seriously jeopardise the biodiversity of any aquatic environment. @JASEM

Acute toxicity evaluation of water extract stem barks of Balanites aegyptiaca on adults of three different fish species

“…These two plants have been used for fishing in the ALNP and B. aegyptiaca is grown near the river sides of the area and largely used as an effective fishing method during the dry season. This is in agreement with the study of Neuwinger (2004) and Abalaka et al (2014) in which B. aegyptiaca was in the first listing order among the piscicide plants widely used in Africa. Therefore, the efficacy of this commonly used plant piscicide was evaluated and found to be more toxic than other plant piscicides evaluated on different fish species (Neuwinger, 2004;Absalom et al, 2013;Alhou et al, 2016).…”

“…All fishes subjected for higher concentration levels appeared in a more distressed condition at first, jumping over the surface and gasping air then they became inactive followed by loss of balance and finally sank to the bottom. The behavioral responses against acute concentration of B. aegyptiaca observed in the current studies are in tandem with earlier findings of Ufodike and Omoregie (1994), Absalom et al (2013), Abalaka et al (2014) and Alhou et al (2016). However, at lower concentrations (that is 15.0 and 17.5 mgL -1 ), such physical distress was recorded only for B. nurse within a short time of exposure and the other test fishes showed such behavioral actions after long exposure.…”

“…The decline in pH with time may be due to the production of acidic products of metabolism by the plant material in water. Electrical conductivity increased across the different concentration level, this may be due to the chemical composition of B. aegyptiaca responsible for conductivity (Abalaka et al, 2014).…”

“…This was a real situation of what happened in the actual river when this plant was used for fishing by which the first species that comes out and dazed easily were Cyprinidae and Alestidae, Distichodontidae, Schilbeidae, Bagridae but finally Mochokidae, Clariidae and very rarely Arapaimidae in the ALNP area. This relative difference for piscicide tolerance may be due to the presence of some elaborative breathing organs in the catfish families and an intricate physiology in some fishes that is able to detoxify ichthyotoxins to a level of insignificant toxicity (Abalaka et al, 2014).…”

Investigation of seaweed extracts as a source of treatment against bacterial fish pathogen

“…Maxium survival was observed in the ethanol extarct while lower survival was observed in the aqueous extract as shown in the ( fig 1). (Abalaka et al, 2014) studied the toxicity of ethanol extract of Adenium obesum stem bark in Clarias gariepinus over a 96-h exposure period. The fishes were exposed to different concentrations of 6.25 mgL -1 , 7.50 mgL -1 , 8.20 mgL -1 , 8.80 mgL -1 and 10.00 mgL -1 of the extracts.…”