Journal of Biology, Agriculture and Healthcare www.iiste.org ISSN 2224-3208 (Paper) ISSN 2225-093X (Online) Vol.8, No.2, 2018 24 Effects of Enzyme Supplementation on the Utilization of Sweet Potato (Ipomoea batatas) Meal Based Diets by Broiler Chickens Lauratu Adamu Kurawa 1* Samson Ogundipe 2 1.F.C.T. College of Education Zuba, P.M.B. 61 Garki, Abuja, Nigeria 2.Department of Animal Science Ahmadu Bello University, Zaria, Nigeria Abstract A feeding trial was conducted to determine the effects and optimum levels of replacing maize with sun-dried sweet potato meal supplemented with a multi-enzyme (SDSPM+EZ) in broiler chicken diets. Four isonitrogenous and isocaloric broiler starter and finisher diets were formulated to replace maize at graded levels of 0, 25, 50 and 75 percent. The starter and finisher diets were fed to three replicate groups of birds for four weeks during each phase. Eighteen and fifteen chicks per replicate were assigned during the two phases respectively in a complete randomized design. In the first phase, chicks fed 25% SDSPM+EZ diet had significantly the best (P<0.05) final body weight (786.80g), daily weight gain (26.71g) and FCR (2.27). Performance was also better for the 50% SDSPM+EZ treatment compared to the control group. There were no significant differences in the feed consumption of the birds with up to 50% SDSPM+EZ replacement of maize. Feed cost (N/kg gain) for birds on all SDSPM+EZ diets were lower than for the control group. During the finisher phase, final body weight, daily weight gain, FCR and feed cost (N/kg gain) improved significantly with increasing level of SDSPM+EZ up to 50% maize replacement. At 75% SDSPM+EZ performance was adversely affected. Weight of carcass and breast cut were significantly higher for the 50% and 25% SDSPM+EZ treatment groups. Trend analysis gave optimum replacement levels of 37.5% and 52.50% SDSPM+EZ for maize in starter and finisher diets. It was concluded that up to 50% of maize in broiler chicken diets can be replaced by SDSPM+EZ with satisfactory performance. Keywords: Broiler chicken, Maize, Multi-enzyme, Sun-dried sweet potato meal, Optimum levels 1.0 Introduction Animal protein is an essential component of a balanced diet. It is however, beyond the reach of many people in the developing countries mainly due to the high cost of animal products like meat and eggs. High cost of poultry products is attributed to the high cost of feeds which according to Ogundipe et al. (2003) accounts for 60-80% of poultry production cost. The poultry industry over the years depends mainly on maize as the source of energy in feeds. Energy sources such as sorghum and maize were reported by Okereke (2012) to constitute the bulk (50% to 55%) of the formulated poultry diets. High demand of maize for human consumption and industrial uses coupled with its fluctuating price contribute significantly to the high cost of feed and poultry products. Nutritionists therefore, continue to search for non- conventional, readily available and cost effective alternatives to maize. Sweet potato (Ipomea batatas) is a cheaper root crop that has less competition with human and was reported to yield more calories per hectare than maize (Mwangi, 2011). Sweet potato is a good source of energy with carbohydrate accounting for 80% to 90% of the dry matter and starch is the main (75% DM) component of the carbohydrate (Dominguez, 1990). Woolfe (1992) also reported that sweet potato and maize have comparable metabolizable energy of 14.8 and 14.5MJ/kg respectively. In most studies carried out with sweet potato (SPM) meal in poultry diets, there were general trends of depressing performance with increasing level of SPM (Agwunobi, 1999; Maphosa et al., 2003; Ayuk and Essien, 2009; Afolayan, 2010). The poor performances were associated with the anti-nutritional factors (ANFs) in the sweet potato. According to Aina and Fanimo (1997) sweet potato contains tannin, phytate, oxalate and trypsin inhibitors which may affect nutrient utilization and depress performance. Addition of exogenous enzymes was reported to inactivate ANFs, improve digestion and enhance nutrients utilization of some feedstuffs (Bedford,1996; Samarasinghe and Wenk, 2000; Meng and Slominski,2005). There is however limited information on the use of exogenous enzyme with sweet potato meal diets. Enzyme supplementation of sweet potato meal-based diets may also deactivate or reduce the ANFs in sweet potato meal and enhance its utilization as a poultry feed ingredient. Considering that sweet potato is cheaper than maize, its inclusion at high levels in broiler chicken diets may lower feed cost and increase availability of poultry meat for human consumption. The main objective of this study was therefore, to evaluate the effects of enzyme supplementation of sun- dried sweet potato meal as a replacement for maize in broiler chicken diets. 2.0 Materials and Methods 2.1 Experimental Site The study was conducted on a research farm at Gwagwalada, Abuja (latitude 8 0 55’22” and 9 0 14’ 34” N and brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by International Institute for Science, Technology and Education (IISTE): E-Journals