CHAPTER ONE
         INTRODUCTION
- Background to the Study
Poultry is an important source of protein to the ever-expanding human population. The cost of feed has been identified by farmers as the major constraint in poultry production (Munyawu et al., 1998). The poultry producers have experienced a rise in the cost of production due to the increasing cost of feed. The cost of maize which makes 65 % of the current poultry feeds is very high (Scott, 1995; Mutetwa, 1996). Maize has a lot of industrial and domestic uses, such as bio-fuel, brewing, starch industries and for human food. However, inadequate production of this grain and the intense competition for maize between man, industries and livestock has made poultry rations to be expensive. This situation has forced poultry farms and feed millers to search for alternative feed ingredients which are available in large quantities, cheaper and can substitute for the scarce and expensive maize. Some of these feed alternatives are sweet potato (Ipomoea batatas) and their peels, which have great potentials as energy sources in poultry nutrition.
Prices of poultry products, especially eggs keep rising as a result of the rise in the costs of feed, which constitute between 60-80% of the total production costs (Nuhu et al., 2008). The conventional energy feed sources constitute between 40-65% of formulated poultry diets and have high price tags as a result of their numerous alternative uses (Afolayan, 2010). Among these sources, maize is the most widely employed for poultry feed formulation (Vantsawa, 2001; Afolayan et al., 2012). In order to step down the problem of high and unstable price situation and save the poultry industry from collapse, there is need to broaden the energy source base by assessing unconventional feedstuffs (Afolayan et al., 2012). Maize and sweet potato have comparable metabolizable energy values of 14.5 and 14.8 Kcal respectively (Woolfe, 1992). The digestibility of sweet potato carbohydrate fraction is reported to be above 90% (Ravindran, 1995). However, the level of starch decreases with period of storage and instead the level of reducing sugars, total sugars and total dextrins increase (Woolfe, 1992). Sweet potatoes have also been reported to exhibit trypsin inhibitor activity ranging from 20 to 90 % inhibition (Woolfe, 1992). However, Ravindran (1995) reported that trypsin inhibitor levels present in sweet potato tubers are low and should not be a cause for concern under practical situations. A study carried out in Nigeria recommended 27 and 30 % levels of sweet potato in the starter and finisher diets of poultry, respectively (Agwunobi, 1999). However, Woolfe (1992) reported having replaced 50 to 75% of maize in poultry feed with dried sweet potato flour without adverse effects on the growth of broilers.
The pollution caused by the potato peels as waste product has become an environmental concern. It poses a lot of problems for disposal especially during the wet season as it decays easily and pollutes the environment. Potato is processed into value added products by fast food industries. Sweet Potato is usually peeled during processing either by steam, lye or abrasive peeling methods depending on the type of products desired. However, large quantities of peels are generated which represent a severe disposal problem with increasing awareness and aims of minimizing environmental impact and sustainability (Schieber et al., 2009). Potato peels contain some nutritionally and pharmacologically interesting compounds such as polyphenols and glycoalkaloids which may serve as natural antioxidants and precursors for steroid hormones (Schieber et al., 2009). Potatoes are good sources of energy due to their high carbohydrate content. They also contain some protein and are rich in organic micronutrient such as Vitamin C, B vitamins and an appreciable level of minerals. Sweet potatoes are also a very valuable source of feed for all classes of livestock (Woolfe, 1992). The tubers are relished by pigs and cattle. In 2007, half of the sweet potato tuber production went into animal feeding in United State of America (USA) and United Kingdom (Lebot, 2009; Chittaranjan, 2007). Sweet potatoes can be used on-farm or as an ingredient in commercial compound feeds (Scott, 1992; Gupta et al., 2009). The peels, which are the major portion of processing waste, represent a severe disposal problem to the industry since wet peels are prone to rapid microbial spoilage. Potato peels though a waste product of the food industry is a source of high value compounds (Schieber et al, 2001).
Japanese quails (Coturnix coturnix japonica) are small-sized, early maturing, hardy and prolific birds (Robbins, 1981). They come into egg production between the 5th and 6th week of life, but adult plumage is not attained until the 12th week of age (Martins et al., 1998). The eggs are small, mottled and weigh between 10 and 13g each (Edache et al., 2003a; Musa et al., 2008) with egg fertility and hatchability levels of 90% and 65% respectively (Edache et al., 2003b). The meat and eggs are low in body fat and cholesterol (Schwartz and Allen, 1981) which is of public health significance. Persons prone to high blood pressure and related diseases could consume these products with less risk. Crude protein diet content of 20% has been recommended for optimum egg production in Japanese quails (Edache et al., 2003a; Akpa et al., 2008). The usual high inclusion of maize in poultry diets translates into high cost of feed because of seasonality of production and competition for maize by man (Agbede et al., 2002). According to Bamgbose et al. (2004) maize accounts for about 45 to 55% of poultry feed. This necessitates the need to replace maize either partially or totally in poultry diets to reduce overall cost. Increasing use of alternatives to maize has been recommended (Ani, 2007; Ani and Omeje, 2007; Obikaonu and Udedibie, 2007).
Currently, very few information exist on the use of sweet potato and the peels in Japanese quail diets in Nigeria.
  Justification
The Nigerian poultry industry is faced with a lot of problems that have resulted to a gross shortage of meat to meet the population challenge in the country and there is acute shortage of animal protein in the diet of an average Nigerian (FAO, 2006). This is due to the high cost of conventional protein and energy concentrates, increasing competition between man, industries and livestock for the available grains, price fluctuations and unavailability of the feed ingredients for the formulation of animal feeds (Duru and Dafwang, 2010). Profit maximization cannot be attained unless the birds are fed diets at lowest costs. There is need to search for non-conventional feed resources that are cost-effective, non-toxic and readily available and alternative sources of energy concentrate. Sweet potato and the peels can be a good alternative source of energy in poultry ration.
The main aim of this research is to evaluate the effect of Sweet potato and its peels as alternative energy sources on the growth and laying performance of Japanese quails.
Objectives of the study
The objectives of the study are to investigate: The effect of:
