飼料甘藷品種(系)產量比較及其胰蛋白酶活性分析

Abstract

甘藷可加入飼料中作為畜禽類的食物，但甘藷中所含的trypsin inhibitor會降低甘藷蛋白質的代謝利用率，進而限制甘藷作為飼料的應用性，過去的研究結果建議選擇trypsin inhibitor活性較低的甘藷供人類及動物食用。本研究調查台灣常見的飼料用甘藷的trypsin inhibitor活性，結果顯示在飼料甘藷品種 (系) 中，台南18號、台農17與31號甘藷的trypsin inhibitor活性均高於70%，台農10號是目前台灣飼料甘藷使用最普遍的品種，其trypsin inhibitor活性為52.6%。本研究進一步探討3種加熱處理法 (包括水煮、微波及烘烤) ，對甘藷trypsin inhibitor活性的影響，結果顯示水煮處理可有效地降低甘藷的trypsin inhibitor活性，但有些甘藷品種仍會保有部份trypsin inhibitor活性。在飼料甘藷中，品系CYY99-68具備產量高 (66.12 ± 0.85 ton/ha)且trypsin inhibitor活性低 (32.4%) 的優點，可作為飼料用甘藷之用途。 Sweet potatoes have been used to feed animals. However, the trypsin inhibitor of sweet potatoes prevents animals from metabolizing proteins, and that reduces the practical application of using sweet potatoes as animals’ food. Thus, previous studies recommended selecting sweet potatoes with lower trypsin inhibitor activity for food applications. The trypsin inhibitor activity of Taiwanese sweet potato varieties (lines) was analyzed in this study. For animal feed sweet potatoes, the trypsin inhibitor activity of TN18, TNG17, and TNG31 was higher than 70%. On the other hand, the trypsin inhibitor activity of TNG10, the most popular animal feed sweet potato variety in Taiwan, was approximately 52.6%. The influence of thermal processing including boiling, microwaving, and baking on the trypsin inhibitor activity of sweet potatoes was also analyzed in this study. The boiling treatment successfully reduced the trypsin inhibitor activity of sweet potatoes. However, some sweet potatoes retained partial trypsin inhibitor activity after boiling treatment. An experimental line named CYY99-68 had high yield (66.12 ± 0.85 ton/ha) and low trypsin inhibitor activity (approximately 32.4%). Therefore, CYY99-68 was a good sweet potato variety for the purpose of animal feed.