1.1 Background of the study
Aquaculture is an important weapon in the global fight against malnutrition and poverty, especially in developing countries (Tacon, 2011). The consumption and demand for fish as a cheap source of protein is increasing in Africa due to the country’s poverty. Fish farming or culture (an aspect of aquaculture) is an integral part of the overall agricultural production system in Nigeria. The main species cultivated in Nigeria are tilapias, catfish and carp; However, the African catfish (Clarias gariepinus) is the most widely bred (Agbede et al., 2013). A number of studies looked at different sources of protein for fish feed, but the results were inconsistent. Unfortunately, attempts by feed manufacturers and nutritionists to replace the fishmeal component of practical fish feeds with alternative sources of protein have generally resulted in decreased feed efficiency and growth (Tacon and Jackson, 2015).
The African catfish (Clarias gariepinus) remains the most cultured species in Nigeria and is appreciated by consumers for the quality of its meat. The African catfish is an excellent species for aquaculture, as it is omnivorous, grows fast, and tolerates relatively poor water quality (Amisah et al., 2019). The fish is mostly cultured in earthen ponds. However, it can be cultured in other systems, such as tanks and hapas. With the recent breakthrough in its culture and management, a good number of entrepreneurs have picked up interest in its commercial culture, while numerous citizens culture it in homestead ponds, at their backyards, sometimes in polyculture with tilapia (Oreochromis niloticus). Live-catfish market is now a common site in many cities and towns, all over Nigeria. The product is mostly smoked and the fresh one is used in making ‘pepper soup’, which is a delicacy in many metropolitan restaurants.
In spite of the above progress, the success story of aquaculture in Nigeria is still largely dependent on imported extruded feed using the limited foreign exchange of the state. Feed inputs thus constitute up to 40%-60% of the total farming cost. This scenario is unacceptable, as it reduces the profit margin of the farmer. Hence, various researches are on-going, especially in the area of feed development. The main focus in fish feed research is to replace or substitute the often imported, expensive fish meal component, with readily available, cheaper, alternative source of protein.
A number of crop materials are being investigated for their potential to supplement or even replace fish meal (Chris, 2011; Bello and Nzeh, 2013; Booth and Wickens, 2018; and Pillay, 2014). Moringa oleifera has been identified to hold the potential to make contributions to fish culture.
Moringa Oleifera is a member of moringaceae a miraculous and multipurpose tree that thrive in both tropical and subtropical condition (Richter & Becker, 2013). Moringa oleifera leaves contain 2 times the protein of yoghurt, 7 times the vitamin C of oranges, 3 times the potassium of bananas, 4 times the vitamin A of carrots and a lot more calcium than is available in milk (Fahey, 2005). Despite the high crude content of Moringa leaf meal, there is little information regarding the utilization of Moringa leaves in fish feed. However, it has been found that Moringa leaves could be constituted in dietary protein of fish feed (Richter & Becker, 2013).
Moringa leaves have unique qualities that make it a potential replacement for soybean meal or fish meal in non-ruminant diets.
According to (Onimisi et al., 2017). M. oleifera can be included up to 30% in rabbit diet without any adverse effect on the growth performance. It can also be included up to 20% in the diets of laying birds without any adverse effect on their production and performance (Kakengi et al. 2017). Moringa leaves meal contains 27.51% crude protein, 19.25% crude fibre, 2.23% crude fat, 7.13% ash, 76.53% moisture, 43.88% carbohydrate and 1296.00 Kj/g calories (Oduro et al., 2008). The leaves are non-toxic and found to be loaded with nutrients necessary for the growth and development of animals.
Several studies have shown that M. oleifera leaves are highly medicinal as they perform several functions such as being antibacterial (Egbuikwem and Sangodoyin, 2013), antifungal (Prston et al., 2010), antidiabetic, antitumor, anti-ulcer, antioxidant, anti-cancer as they are used in the treatment of the digestive system. Medicinal plants contain a vast range of pharmacologically active ingredients as each herb has its own unique combination and properties. Herbs contain ingredients which possess several effects that are combined in the one medicine (Phondani et al., 2010; Kamboj, 2000). Moringa seed powder has antibacterial properties that make it useful as a natural clarifier for water purification systems and fish ponds (Aruna and Srilatha, 2012).
In Nigeria, there is awareness creation campaign as to the value of this leaf and people have started to eat it and grow it in backyards. Because information is scanty on the utilization of Moringa leaves as feed supplement for fish, the present study will investigare the feasibility of using varying levels of Moringa oleifera leaves as a protein source in the diet of African cat fish Clarias gariepinus.
1.2 Statement of the problem
The failure of aquaculture to meet the challenge of closing the widening gap between fish supply and demand in Nigeria, results from a number of factors including lack of quality feeds. Compost cribs and occasional animal droppings are usually the main feed input in ponds. These, however, can only promote limited growth and further growth is restricted by insufficiency of nutrients from primary production (Omole, 2016). Further growth is only possible through provision of supplementary feed to sustain the increased demand for nutrients.
The high cost and fluctuating quality as well as the uncertain availability of fish meal have led to the need to identify alternative protein sources for fish feed formulation (Lawson, 2015). Therefore, in order to attain more economically, sustainable, environmentally friendly and viable production, research interest has been directed towards the evaluation and use of non-conventional sources of plant protein. Researchers of aquaculture industries aim at exploring alternative, cheaper protein sources for use as fish meal replacers in aqua feeds. The decrease in global production of fish meal clearly demonstrates that the sustainability of this industry will depend on the sustained supply of plant proteins for aqua feeds. Currently fish farmers use cereal bran, kitchen leftovers and green leaves as fish feed.
Instability in the fishmeal supply has led to sharp increases in price beyond the reach of many resource-poor fish farmers. Moreover, there are ethical concerns about feeding fish to non-piscivorous fish (Ogunji and Warith, 2011). Also, there are social concerns over feeding farmed fish with wild fish which could be used directly for human consumption (Olaniyi et al., 2013). This somewhat contradicts the anticipated role of aquaculture in food security and augmenting dwindling supplies from natural stocks particularly in nutritionally deficient areas of the world.
Several studies have shown that vegetable protein sources have high potentials for supplying fish with required protein needed for their maximum productivity (Nwanna et al., 2008). Some of the plant protein sources that have been investigated in an attempt to find substitutes for fish meal in the diets of fishes include; Leucaena, Leucaena leucocephala, Sesbania, Sesbania sesban, Sweet potato, Ipomoea batata, Mulberry, Morus sp., alfalfa, Medicago sativa, Acacia, Acacia auriculiformis, Papaya, Carica papaya, Water hyacinth, Eichornia crassipes, Duckweed, Lemna polyrhiza, Duck lettuce, Ottelia alismoides, Water snowflake, Nymphoides indicum and Peanut, Arachis hypogaea (Ghasi et al., 2010). In most of these studies the leaf meals could only replace < 25% of fishmeal protein.
Recently, researchers have increasingly been paying attention to Moringa (M. oleifera Lam). Moringa is an indigenous plant found growing wild in Northern India and Pakistan. It was introduced into South- East Asia during the early eras, and now cultivated throughout the tropics. In many places, it is also found more or less naturalized. It holds a considerable potential for becoming an ingredient for animal and fish because of its high nutritional quality that is comparable to other feed protein source. This study therefore will examine the effect of varying levels of Moringa oleifera leaves on the growth performance and protein level of African catfish (Clarias Gariepinus).
1.3 Objectives of the study
The main objective of the study is to examine the Effect of varying levels of Moringa oleifera leaves on the Growth performance and protein level of African catfish (Clarias gariepinus).
Specifically, the study sought to examine:
- The growth performance, nutrient utilization and survival parameters of Cat Fish (Clarias gariepinus) fed with varying inclusion level of Moringa oleifera.
- The initial and final carcass proximate composition of Clarias gariepinus fed with different inclusion levels of Moringa oleifera leaf meal (MOLM).
- The water quality parameter of the experimental tanks’ growth fed with varying inclusion level of Moringa oleifera.
1.4 Significance of the study
Moringa is said to be the new hope in efforts at minimizing malnutrition and various related ailments. The leaves of this plant have been reported to have high amounts of essential amino acid with the right balance, as well as high amounts of minerals and vitamins (Fuglie, 2019).
Moringa oleifera is a highly valued plant, distributed in many countries of the tropics and subtropics. It is a non-leguminous tree with a high crude protein in the leaves (251g/kg DM) and negligible content of tannins and other anti-nutritional factors. It has an impressive range of medicinal uses with high nutritional value. Different parts of this plant contain a profile of important minerals, and are a good source of protein, vitamins, -carotene, amino acids and various phenolics. Every part of moringa tree is said to have beneficial properties that can serve humanity. Nutritional analysis indicates that Moringa leaves contain a wealth of essential, disease preventing nutrients. They even contain all of the essential amino acids, such as methionine, cystine, tryptophan, as required by aquatic animals. This is unusual for a plant source. Based on a number of reports on the nutritional/medicinal values of moringa, it is being promoted as a “healthful” food, used traditionally to combat a number of common ailments. Since the dried leaves are concentrated, they contain higher amounts of many of the nutrients, except Vitamin C. Leaves and pods of Moringa therefore, offers an alternative source of protein to fish.
In view of the potentials of M. oleifera, this work will focus on the effect of varying levels of Moringa oleifera on the growth performance and protein level of the African catfish (Clarias gariepienus).
1.5 Scope of the study
This study will investigare the effect of varying levels of Moringa oleifera on the growth performance and protein level of the African catfish (Clarias gariepienus). The study will be carried out in Uyo, Akwa Ibom state while the experiment will be carried out in the laboratory at the Faculty of Agriculture Farm, University of Uyo, Uyo, Nigeria.
1.6 Limitation of the study
In executing this study, the researcher encountered some constraints that affected the progress of the research. These constraints were insufficient finances, inadequate time, unavailability of materials and the effect of Covid-19 pandemic.