ABSTRACT

An experiment was conducted to investigate the effects of using two different enzyme substrates on the performance of broilers fed peeled cassava root meal (PCRM), in a 3 x 3 factorial arrangement in a completely randomised design experiment. One hundred and eighty-nine broiler chicks aged 14 days were assigned to nine experimental diets where PCRM replaced maize at 0, 50 and 75 percent levels. The diets were formulated to be roughly isonitrogenous and isoenergetic containing starter (15-36 days; 24% CP, 2800 Kcal/kg-1 ME) and finisher (37-58 days; 21% CP, 2800 Kcal/kg-1 ME) and 200ppm of enzyme (Nutrase xyla and Roxazyme G) were added to the diets. Results indicated that Nutrase xyla and Roxazyme G supplementation increased ADFI in the starter and finisher phases at all levels of PCRM inclusion (P<0.05). The effect of nutrase xyla and roxazyme G

supplementation on FCR was positvely significant in the finisher phase (P<0.05). Roxazyme G supplemented diet at 50% PCRM had the best least cost value in terms of feed cost per kg weight gain. There was an increase in dressed weight percentage in nutrase xyla and roxazyme G supplemented diets at 50% PCRM (P<0.05). Nutrase xyla supplemented diet had increase significant effect (P<0.05) on dry matter and metabolizable energy retention. Nutrase xyla and roxazyme G supplemented diets had no significant effect (P>0.05) on edible organs (heart and gizzard). It is concluded that enzyme supplementation on PCRM-based diet had tremendous beneficial effect on production parameters.

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.