CHAPTER ONE
INTRODUCTION
BACKGROUND OF THE STUDY
Recently, the fear about the future availability of energy feeds for use in the farm animal diets, around the world has been evident of discussion at various meetings and conferences as revealed by Anigbogu and Adekule-Agbale (2013).The relevance of animal protein in human and animal nutrition cannot be over emphasized (Owen et al., 2009, Owen and Amakiri, 2009). In recent times, there is significant short fall between production and supply of animal protein to feed the increasing world population (Anigbogu and Adekule-Agbale, 2013; Akpan, et al., 2009). To ameliorate this unacceptable trend, efforts have been directed towards boosting the micro-livestock sector. In Africa, annual quantity of fibrous agricultural residue which is a component of municipal organic waste (MOW) available was put at about 340 million tonnes (Belewu and Popola, 2007). In Nigeria, large amount of sawdust that made up part of municipal organic waste produced annually is estimated to be 30,643,230m2 (Babyemi and Dauda, 2009), and are not utilized for animal feed energy purposes. This results to poor waste disposal in the municipalities, which contributes to environmental pollution that constitutes public nuisance and eyesore according to Anigbogu and Madu-Ijeoma (2016) and Anigbogu and Obioma (2015). In Nigeria, this enormous amount of sawdust represents valuable material for future biotechnology exploitation for animal feeds. If this huge amount of sawdust could be recycled or converted to useful feed stuff such as Life-enzyme, based on the findings of Anigbogu and Madu-Ijeoma (2016), our environment will be cleaned of pollution, thereby help to improve human health (Anigbogu and Ezekwe 2013; Belewu and Popola 2007).
In the South-East Nigeria, the scarcity of feed for farm animal husbandry has been a constraint militating against the animal industry, while there has been abundance of sawdust from the wood-milling industries causing pollution (Anigbogu and Ibe, 2005). There has been calls for research on the use of sawdust as suitable feeds in the farm animal feeding system, to help improve animal production, health and to control our environment of pollution as revealed by Anigbogu et al.(2011a). The limitation in the use of sawdust as feed is that, it contains about 62.1% crude fiber, a ligno-cellulosic plant material that has crystalline nature of the cellulose and recalcitrance of lignin (Anigbogu, 2011). This lignin constitutes a physical barrier to the utilization of sawdust. Though, the physical barrier of lignin could be broken down either by physical, chemical or biological treatments (Anigbogu and Ezekwem 2013). Based on the findings of Anigbogu (2011), the biological treatment of fibrous materials is not entirely new, and the biotechnological techniques are gradually being introduced in the field of animal nutrition and production throughout the globe. The introduction of the recent microbial technology using efficient microbes on the innovation of solid-state fermentation (SSF) technology based on the findings of Anigbogu et al.(2009a), and Anigbogu et al.(2011b) may be appropriate for the biological conversion of ligo- cellulosic wastes, such as sawdust to valuable feed resources, and to make enzyme hydrolysis more available in the rumen, this is found (Anigbogu and Madu-Ijeoma, 2015).
The giant African snail (Achatina fulica) known to be omnivorous in nature; has diastic microbes in its specialized crop with symbiotic microorganisms ‘composition. This helps in the breakdown of polysaccharide into simple sugars in the crop. The crop contains a whole series of enzymes, including a cytase (cellulose splitting enzyme), which digest complex carbohydrates and plant cell walls to liberate their contents into valuable feed nutrients mainly protein and energy (Anigbogu et al. 2018).
Globally, it has been noted that, wildlife has great potential for meat production and serves as important source of highly needed animal protein for human race, and are widely accepted as food. The Cane rat (Thryonomys swinderianus) a hystricomorphic rodent, is widely distributed in the African sub-region and been exploited in most areas as source of food and animal protein. It is the most preferred and most expensive meat in the sub-region (Abioye et al. 2008). Feeding is the most essential factor of Cane rats in production captivity, since feed quality and quantity determines the level of output of animals under the intensive husbandry as noted by Adu (2002), and Olomu et al.(2003). In captivity husbandry of Cane rat, poor nutrition leads to sickness and mortality, especially among the young where low weight at birth and maturity has always been a problem. The poor availability of quality grasses and legumes and other feed resources has been recognized to make feeding a major problem, especially in the dry season (Yeboah and Simpson, 2004). So far, the knowledge in feeding Cane rats remains fundamental, and the feeding method used has proven to be inadequate for growth and reproduction (Yeboah and Adamu, 1995).
Grass being a major feed for Cane rat production, is generally poor in protein, high in fiber and low in digestibility, and generally is being constrained by inadequate supply of quality nutrients (Afocha and Anigbogu, 2011b).This is because of its poor metabolism (Alawa and Oyarole, 2004). Furthermore, in an attempt to reduce or eliminate the problem of feed scarcity, other feed resources like agro and industrial by-products which constitute a major bulk of municipal organic wastes, should be exploited as feeds for livestock and poultry (Anigbogu and Uchealor, 2014).
1.2 STATEMENT OF PROBLEM
Globally, wildlife has great potentials for meat production and serves as an important source of the highly desired animal protein to the people of Africa, both in urban areas and rural communities (Fonweban and Njiwe, 1990). The preference for such merit or the meat of commercially available game animals is widely accepted (Baptist and Mengah, 1986). However, with ever increasing human population and obvious protein shortage in Africa, there is the need for an exploration of other means to provide readily accepted meat or short terms basis.
Among the wild rodents, the cane rat, or cane rat or cane cutter is the most preferred (Goffey, 1981). Cane rat (Thryonomys swinderianus) is a wild hystricomophic rodent widely distributed in the African sub-region and exploited in most areas as a source of animal protein (NRC, 1991). Being the most preferred and one of the most expensive meats in West Africa including Nigeria, Togo, Benin, Nigeria and Cote d’ Voire (Baptist and Mensah, 1998; Asibey and Addo, 2000), it constitutes to both local and export earning of most West Africa countries (NRC, 1991; Yeboah and Adamu, 1995). To alleviate this problem, attempts are being made in the sub-regional to domesticate the grass cutter (NRC, 1991; Addo, 2002) and make it more readily available, gain economic benefit and also reduce the environmental destruction that accompanies its collection from the wild. Efficiently producing grass cutters in captivity demands that adequate nutrition is provided to ensure high productivity. However, grass cutter especially in the dry season poses a major challenge to produce in Nigeria.
Despite the role cane rat rearing plays in the livelihood of most Nigerians and the contribution to the daily protein intake, if continued, cane rat meat cause a source of food-borne illnesses especially under the condition in which animals are handled, slaughtered, transported and sold in Nigerian markets. Prescott, et al., (2002) shown that food items especially meat, are not only of high nutritional value to those who consume them but often are ideal culture media for microbial growth, meat is one of the most perishable foods, indicates composition is ideal for growth of a wide range of spoilages bacteria (Mayr, et al., 2003).
Mukhopadhyay et al., (2009) also reported that fresh raw meat like cane rat meat has been implicated for a number of meat borne infections and intoxications in several countries. This is because both pathogenic and non-pathogenic organisms live in the gastro intestinal tract (GIT) of cane rat which can be transformed onto the meat under faulty and poor processing conditions.
The advocacy for domestication of cane rat becomes stronger as it accepts indoor housing with about 90% of animals acclimatizing to domestic housing within three months (Asibey and Addo, 2000), with the acceptability of the meat among Nigerians, regardless of their religious of faith and social status further underscores the importance of domesticating this animal.
Due to the insatiable demand for the cane rat meat, some people have resorted to use poisons as bait to catch wild cane rat and this poses a serious health threat.
The inadequate supply of animal protein in developing countries has been attributed to inadequate production and high cost of conventional sources of animals protein (poultry, goat, meat, beef, mutton and pork) and cane rat meat, hence, an average Nigerian consumes only about a quarter of his minimum daily protein requirement (Oke, et al., 2004). To this end there has been increase in the consumption of bush meat. This increase has bridged the supply and demand protein gap (Abulude, 2004).
1.3 OBJECTIVES OF THE RESEARCH
The main aim of this study is to carry out a microbial evaluation in the unit operation of the processing of cane rat. The specific objectives of this study are to:
1. Determine the microbial status of fresh cane rat
2. Determine the critical control points at which microbes are likely to contaminate the fresh cane rat along processing line.
Isolate, identify and characterize the micro organisms present in the fresh cane rat during processing.