production values of birds fed 10% sweet potato peel meal (82.31days) was statistically similar with birds fed 0% sweet potato diets (82.31). There was no mortality recorded during the grower and laying phase. Inclusion of sweet potato and sweet potato peel meals in the diets of Japanese quails did not result in any detrimental effect on overall performance. Thus substituting maize with sweet potato meal at 10% inclusion and sweet potato peel meal at 10% inclusion in Japanese quails diet resulted in enhanced growth and egg production performance at the least cost. At the growing phase, diets containing sweet potato meal at 10, 20 and 30% levels of inclusion reduced cost of production by 1.97%( 0.62), 3.21% ( 1.01) and 5.35% ( 1.68) respectively while diets containing 10 and 30% sweet potato peel meal reduced the cost of production by 59.04% ( 18.55) and 66.58% ( 66.58) respectively.

1.0                                                       INTRODUCTION

1.1       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

1

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

2

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,