Department of Animal Production Technology, Federal College of Agriculture, P.M.B.7008, Ishiagu, Ebonyi State, Nigeria.
Biotechnology Programme, National Root Crops Research Institute, P.M.B, 7006, Umudike, Abia State, Nigeria.
Trop Anim Health Prod. 2021 Mar 15;53(2):207. doi: 10.1007/s11250-021-02656-9.
The competition for maize and soybean between humans and livestock for food has led to an increase in the cost of livestock feeds. Therefore, this has necessitated the search for alternative non-competitive feedstuffs in order to partially replace maize and soybean in small ruminant diets. The use of cassava products as a partial replacement for maize and soybean in small ruminant diet has been investigated. Cassava is a tropical crop, and its fodder is rich in crude protein (CP), minerals and vitamins with about 85% of the CP fraction exist as true protein. Cassava by-products are also high in nutrients and could contribute significantly to the nutritional needs of sheep and goats. Specifically, cassava leaves are high in CP (25.10%) with an amino acid composition similar to soybean. Evidence also exist that ruminal degradability of cassava fodder is similar to that of maize and soybean with comparable outflow rates (75%). However, the use of cassava fodder in livestock production is limited by the presence of cyanogenic glucosides (linamarin and lotaustralin) that releases hydrogen cyanide (HCN) known to cause pathophysiological changes in the liver of sheep and goats. Importantly, several processing techniques are well known to reduce or eliminate the concentrates of cyanogenic glucosides in cassava with great success. Blood chemistry and production indices of sheep and goats fed differently processed cassava by-product-based diets have been evaluated by different authors. This review revealed that cassava root sievate meal, cassava root meal and cassava peel meal are low in CP (2.29, 3.40 and 7.05%, respectively), while cassava leaf meal is high in CP (32.43%). Feed conversion efficiency of sheep and good fed cassava leaves were 9.49 and 11.24, respectively, indicating that goats utilize cassava leaves better than sheep. It is concluded that cassava by-products are low in quality protein and should be supplemented with other rich protein sources before their use in ruminant diets.
人类和家畜对玉米和大豆作为食物的竞争导致了牲畜饲料成本的增加。因此，为了部分替代小反刍动物日粮中的玉米和大豆，有必要寻找非竞争性饲料。人们已经研究了将木薯产品作为小反刍动物日粮中玉米和大豆的部分替代品。木薯是一种热带作物，其饲料富含粗蛋白（CP）、矿物质和维生素，其中约 85%的 CP 以真蛋白形式存在。木薯副产品也富含营养物质，可以极大地满足绵羊和山羊的营养需求。具体来说，木薯叶的 CP 含量很高（25.10%），其氨基酸组成与大豆相似。也有证据表明，木薯饲料的瘤胃降解率与玉米和大豆相似，流出率相当（75%）。然而，由于木薯饲料中存在氰苷（亚麻苦苷和卡茄碱），会释放出氢氰酸（HCN），已知这会导致绵羊和山羊的肝脏发生病理生理变化，因此其在畜牧业中的应用受到限制。重要的是，有几种加工技术可以成功地降低或消除木薯中氰苷的浓度。不同作者已经评估了用不同加工方法处理的木薯副产品饲料喂养绵羊和山羊的血液化学和生产指标。这篇综述表明，木薯根筛渣粉、木薯根粉和木薯皮粉的 CP 含量较低（分别为 2.29%、3.40%和 7.05%），而木薯叶粉的 CP 含量较高（32.43%）。用木薯叶喂养绵羊和山羊的饲料转化率分别为 9.49 和 11.24，表明山羊比绵羊更能有效地利用木薯叶。结论是，木薯副产品的蛋白质质量较低，在用于反刍动物日粮之前，应补充其他富含蛋白质的来源。
