本研究之目的為開發國內生產之樹薯，作為替代進口玉米為家禽飼料之原料，以因應全球氣候變遷造成穀物減產的影響。本研究蒐集台灣高雄(K)、台南玉井(Y)、桃園(T)及南投地區之烏枝仔(D)、白骨(W)、黃金(M)、麥芽(G)等四種民間種植之樹薯，分別分析其組成成分。依據成分及產量之考量因素，選擇以種植面積較大之台南玉井之樹薯進行後續實驗。試驗分兩階段，實驗動物為愛拔益加之白肉雞。試驗一以台南玉井種植之樹薯，於雞隻4、6及13週齡各進行一次代謝試驗。試驗二為生長試驗，400隻肉雞分為4組，分別餵飼不同濃度之樹薯。依據NRC(National Research Council）1994年肉雞之標準及樹薯成分配製肉雞育雛料、生長料及肥育料。每期飼料又分為四組，其中樹薯取代玉米成分之0、10%、20%及30%。紀錄並分析雞隻之飼料消耗量、體重、飼料效率，隨機抽樣進行屠體分切比較及官能品評。試驗一結果顯示樹薯於白色肉雞之真代謝能(TME, True Metabolizable Energy)為3628 kcal/kg。試驗二結果顯示肉雞飼養到達上市體重時，以30%樹薯取代玉米之雞隻體重顯著低於其他組 (P<0.01)，飼料效率亦明顯較差。所有餵飼樹薯之雞隻於育雛期時之增重雖較控制組低，但於生長期及肥育期結束時，除了30%取代率組以外，都能趕上控制組的體重，且飼料效率亦沒有顯著差異。屠體性狀分析顯示各組間之部位分切率皆無顯著差異，且肉質之官能品評分析亦顯示餵飼樹薯不影響肉質。綜言之，本研究揭示樹薯可用於取代肉雞飼量中之玉米，取代率可達20%而不會影響肉雞之生長表現、屠體性狀及肉之品質。
The purpose of this study is to develop the locally grown cassava as poultry feed substitutes for corn in order to solve the crop shortage due to the climate change. Cassava from different region of Taiwan were collected during the year of 2012 and were analyzed for their compositions. Two experiments were conducted using cassava from Yuchin, Tainan. Experiment one was designed to determine metabolizable energy (ME) of cassava. Experiment two was designed to investigate replacement rate of cassava using 400 broilers and tested for four different cassava levels in the diet. ME of cassava for broiler was found to be similar to corn (3628 kcal/kg). In experiment two, cassava were used to replace 0, 10%, 20% and 30% of corn in starter diet, growing diet and finishing diet. Four hundred broilers were divided into four groups and replacing with feeds containing different levels of cassava. Feed consumption and body weight gain of the broilers were recorded each week and the feed conversion rate (FCR) was calculated. Results showed that the body weight of the 30% cassava replacing group chicken were lower than other groups (P<0.01) and the FCR was not as good as other groups. At the end of the brooding period, the body weight of control group was greater than all cassava replacing chickens; however, as the chickens grew toward the end of growing and finishing period; there was no significant difference of FCR between the cassava replacing groups and the control group. In summary, without affecting the growth performance, carcass characteristics and meat quality of the broilers, cassava can be used as broilers feed substitutes for corn in concentration up to 20%.
