The Effect of Different Enzyme Substrates on the Performance of Broilers Fed Peeled Cassava Root Meal (PCRM) Based Diet

1.0 Introduction
A serious competition exists between the feed industry and other channels in the food chain (especially man) over conventional feed ingredients such as maize and soyabean. This has resulted in the high cost and scarcity of these conventional feedstuffs. Poultry feed producers are thus faced with the task of finding alternative feedstuffs that will not compromise quality. The search for such alternatives has exercised Animal Nutritionists in Nigeria for over a decade (Onyimonyi and Okeke, 2002; Onyimonyi and Onukwufor, 2003; Oke et al., 2005; Onyimonyi and Okeke, 2005; Tuleun et al., 2005).
Cassava, has been used as an alternative energy source and its inclusion in diets for poultry has been extensively studied (Tewe and Egbunike 1992, Eruvbetine 1995, Adegbola, 1977). Nigerian cassava production is by far the largest in the world; a third more than production in Brazil and almost double the production of Indonesia and Thailand. The Food and Agriculture Organization of the United Nations estimated 2002 cassava production in Nigeria to be approximately 34 million tonnes(FAO, 2004). The trend of cassava production reported by the Central Bank of Nigeria put the highest estimate of production at 37 million tonnes in 2000 (FMANR, 1997).
The third series provided by (PCU, 2003) had the most conservative estimate of production at 28 million tonnes in 2002. Nigeria's production was targeted at 40 million tonnes by 2005 and 60 million tonnes by 2020 (IITA, 2002). Nigeria, being the world's largest producer of cassava should be able to utilize its vast potential to provide enough of the tuber, not only for human consumption, but also for animal feed, industrial use and export. In animal feed, it can be used as flour after being peeled or chipped with the peels and ground before use. Studies have shown that levels as high as 20% could be used in diets for layers (Tewe and Egbunike 1992) and 40% in broilers (Eruvbetine and Afolami, 1992) and 10% in replacement pullets (Eruvbetine et al., 2002). Onyimonyi and Okeke (2005) reported that 20 percent of the maize content of the diets of grower pigs can be replaced by cassava peelmeal without any deleterious effect on the carcass, organ characteristics and no pathological effects was observed.