Comparative acute toxicity of aloe vera (aloe barbadensis) leaves and roots on fingerlings of african catfish, clarias gariepinus (siluriformes: clariidae)

Thesis Overview

<p> <b><b><b></b></b></b></p><p><b><b><b><b>1.1 &nbsp; &nbsp; Introduction</b></b></b></b></p><p><b><b><b></b></b></b></p><b><b><b><p>The<br>use of plants for healing purpose is getting increasingly popular as they are<br>believed as being beneficial and free of side effect (Leonardo <i>et al</i>., 2000). The use of plant materials as spices,<br>condiments and for medicinal purposes has therefore become more popular and as<br>such more wild plants are being exploited for medicinal purpose. There is therefore no doubt that orthodox<br>medicine itself appears to be strongly anchored on traditional medicine (Nweze,<br>2005). Plants are used for different<br>purposes because some plants contain compounds of various class that have<br>insectidal, piscicidal and molluscicidal properties (Cagauan, 1992). However, the occurrences of these fish poison<br>plants are varied based on location. Different parts of plants which contain<br>toxic substances used in poisoning fish include the roots, seeds, fruits, barks<br>or leaves (Gabriel and Okey, 2009). <br>According to Gabriel and Okey (2009), ichthyotoxic plants used for<br>baiting and stupefying of fish are often crushed and cast into stagnant, slow<br>moving water or spread on mud flats to<br>poison fish. Ichthyotoxic plants have<br>been used as fish poisons or narcosing chemicals by the artisanal fishermen for<br>decades in the harvesting of fish in slow flowing waters (Oribhabor <i>et al</i>., 2014).</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; According<br>to Neuwinger (2004) and Fafioye et al. (2004), the use of fish poison plants<br>and other plant products is one of the methods in traditional methods of fish<br>capture. Plant extracts used as<br>piscicides in capture fisheries and aquaculture are considered advantageous<br>when compared to the back drop of using persistent and synthetic chemicals<br>(Gabriel and Okey, 2009). Phytochemical<br>evaluation indicates that such piscicidal or ichthyotoxic plants contain<br>different active ingredients known as alkaloids such as nicotine, pyrethrum,<br>ryania, rotenone, resin, akuammine, tannins, saponins and diosgenin (Wang and<br>Huffman, 1991). Ichthyotoxins present in these fish poison plants will stun<br>fish when it passes through the gills or in some cases when ingested, it makes<br>the fish to float on the water surface for easy capture (Kritzon, 2003).</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Aloe<br>vera (<i>Aloe barbadensis</i>), a member of<br>the family liliaceae, is a naturally occurring perennial succulent plant that<br>is cactus-like in its characteristics, originating from Northern Africa<br>(Akinyale and Odiyi, 2007). Aloe’s<br>thick, tapered, spiny leaves grow from a short stalk near ground level. Aloe’s relationship to the lily family is<br>evident from the tubular yellow flowers produced annually in the spring that<br>resemble those of the Easter lily (Amit and Shweta, 2016).</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Important<br>pharmaceutical properties that have recently been discovered for the aloe vera<br>gel and whole leaf extracts includes the ability to improve bioavailability of<br>co-administered vitamins on human subjects (Chandan <i>et al</i>., 2007). The<br>biological activities include promotion of wound healing, antifungal activity,<br>hypoglycemic or anti-diabetic effects, anti-inflammatory, anti cancer,<br>immuno-modulatory and gastro-protective properties. Furthermore, an increase in<br>bile flow and bile solids as a result of treatment with the extract suggests<br>stimulation of the secretary activity of the liver cells. The hepatoprotective action is also<br>attributed to preserving the metabolizing enzyme of the liver through an antioxidant<br>activity (Ambrose <i>et al</i>., 1994;<br>Zodape, 2010). In Nigeria, there is a<br>very strong cultural belief in herbal medicare, most often due to the latter’s<br>economic advantage and easier reach compared to the high cost of orthodox<br>medicine. This is more compounded by low<br>literacy levels and often epileptic and grossly inefficient orthodox healthcare<br>delivery system. Since the sudden<br>introduction and widely acclaimed mega-therapeutic potentials of aloe vera and<br>its products in the mid 1990s, and the highly expensive “processed” Aloe vera<br>products, it is a common site to see homestead aloe vera “plantations” at every<br>corner in most towns and villages. This<br>has led to unrecommended and uncontrolled consumption of raw Aloe vera leaves<br>by highly and mighty in the society.</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Reports<br>have been documented in the therapeutic potentials of Aloe vera (Schmidt and<br>Greenspoon, 1993), its toxicity, especially when used parenterally (Brusick and<br>Menge, 1997; Balter, 1992). Report have shown that consumption of Aqueous<br>extract of Raw Aloe vera leaves in the histopathological and biochemical<br>studies in Rat and Tilapia tends to be lethal to fish at as low as 50ppm in<br>water causing 100% mortality within 96 hours (Taiwo <i>et al.,</i>&nbsp;2005). Methanolic extract of Aloe vera’s toxicity have also<br>been tested on rats (Saritha <i>et al.,</i><br>2010). A study on analgesic efficacy and<br>adverse effects of aloe vera in wistar rats have also been carried out (Ghosh <i>et al</i>., 2011). Aloe vera has also been used to study its<br>dietary effects on growth performance, skin and gastro-intestine morphology in<br>rainbow Trout (Oncorhynchus mykiss).</p><p>&nbsp;The African<br>catfish (<i>Clarias gariepinus</i>)<br>belonging to the family clariidae is the most cultivated species in<br>Nigeria. This is attributed to its<br>ability to tolerate a varying range of<br>environmental conditions, high stocking densities under culture condition, fast growth rate,<br>disease resistance, acceptability of artificial feed, high fecundity, good<br>taste and meat quality, ease of artificial breeding, high market value etc (Eyo<br><i>et al.,</i>&nbsp;2014). African catfish (<i>Clarias gariepinus</i>) is one of the highly<br>priced food fish in Nigeria and most parts of the world. An Omnivorous scavenger that eats everything<br>it finds, the African catfish is particularly amenable to the farming practices<br>of smallholders, who comprise the majority of farmers in developing countries<br>(Musa <i>et al.,</i>&nbsp;2012, Ajala and<br>Owoyemi, 2015). African catfish is rated<br>the third most cultured fish in the world (Offem <i>et al.,</i>&nbsp;2010).</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Biologically,<br>the African catfish (<i>Clarias gariepinus)</i>,<br>is undoubtedly an ideal aquaculture species. <br>It is widely distributed, not only in African countries but also in the<br>Netherlands; it thrives in diverse environments, temperate to tropical (Hecht <i>et al.,</i>&nbsp;1996). It is hardy and adaptable principally as a<br>consequence of its air breathing ability, feeds in a wide array of natural prey<br>under diverse conditions, is able to withstand adverse environmental<br>conditions, is highly resistant to diseases, and is highly fecund and easily<br>spawned under captive conditions. It has<br>a wide tolerance of relatively poor water quality and possibly the most<br>exciting feature of the species is its potential for highly intensive culture<br>without prerequisite pond aeration or high water exchange rates and its<br>excellent meat quality (Hecht <i>et al.,</i><br>1996)</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Although<br>this plant, Aloe vera (<i>Aloe barbadensis</i>)<br>have been used in several toxicological studies, little or no information have<br>been documented on its toxic effects in the African catfish (<i>Clarias gariepinus</i>). Also, most of the documented works have been<br>carried out using only the leaves of the plant but in this research, I will be<br>comparing the toxic effect of both the plant’s leaves and roots against the<br>African catfish (<i>Clarias gariepinus</i>).</p><p><b>1.2 &nbsp; &nbsp; Objectives of the study</b></p><p><b></b></p><b><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; The<br>objectives of this research are to:</p><p>a) &nbsp; &nbsp; &nbsp; Investigate the toxicity of Aloe vera (<i>Aloe barbadensis</i>) leaves and roots in <i>Clarias gariepinus</i>&nbsp;fingerlings.</p><p>b) &nbsp; &nbsp; Determine the phytochemical composition of<br>the ichthyotoxic plants, Aloe vera (<i>Aloe<br>barbadensis</i>).</p><p>c) &nbsp; &nbsp; &nbsp; Determine the acute toxicity (LC50)<br>of the aqueous extract of <i>Aloe</i>&nbsp;<i>barbadensis</i>&nbsp;on fingerlings of <i>Clarias gariepinus</i>&nbsp;under 96hours static<br>bioassay.</p><p>d) &nbsp; &nbsp; Compare the toxic effects of Aloe vera (<i>Aloe barbadensis</i>) leaves and roots<br>against <i>Clarias gariepinus.</i></p></b></b></b></b><br> <br><p></p>