Ensiled or oven-dried green tea by-product as protein feedstuffs: Effects of tannin on nutritive value in goats
Ensiled or oven-dried green tea by-product as protein feedstuffs: Effects of tannin on nutritive value in goats
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DOI：
10.5713/ajas.2007.880
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发表时间：
2007-06-01
期刊：
影响因子：
--
通讯作者：
Yokota, Hiro-omi
中科院分区：
文献类型：
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作者：
Kondo, Makoto;Kita, Kazumi;Yokota, Hiro-omi
以山羊为试验动物，研究了笼养和烘干绿色茶副产品（GTB）作为蛋白质饲料的营养价值。为了阐明茶单宁对体外消化率的影响，使用聚乙二醇（PEG）作为单宁结合剂。青贮和干GTB都含有31.9%至32.6%的粗蛋白（CP）的干物质（DM）的基础上。豆粕和苜蓿干草中的酚类物质和单宁含量较低或未检测到，但青贮和干燥的GTB中的酚类物质和单宁含量较高（7.3-10.1% DM作为总可提取单宁）。体外瘤胃蛋白质消化率排序为：豆粕>苜蓿草块>青贮GTB =干GTB。这些饲料的蛋白质过瘤后消化率与瘤体内消化率呈相似趋势，但青贮GTB的消化率显著高于干GTB。PEG的添加提高了两种GTB在瘤胃和瘤胃后的蛋白质体外消化率，表明单宁抑制了GTB的潜在蛋白质消化率。添加PEG对青贮和干GTB蛋白质瘤胃消化率的提高差异不显著，但青贮GTB的瘤胃后消化率增加百分比高于干GTB。在体内消化率试验中，将青贮和干燥的GTB作为豆粕和苜蓿干草块的部分替代品提供给山羊。以DM为基础，以5-10%的比例向山羊提供GTB不会影响营养物质的消化率、瘤胃pH值、挥发性脂肪酸和氨浓度。然而，GTB掺入饲料的进食时间比基础饲料的进食时间长。当GTB青贮饲料分别以总饲料的5%和10%水平提供时，完全进食饲料所需的时间是对照饲料的1.4和1.6倍。这些结果表明，在营养价值方面，青贮和干燥的GTB可作为山羊豆粕和苜蓿干草块的部分替代品。由于适口性降低，建议将GTB以DM的5%掺入饲料中。
Ensiled or oven-dried green tea by-products (GTB) were evaluated in goats for their nutritive potential as protein feedstuffs based on in vitro and in vivo digestibility. To elucidate the effects of tea tannin on in vitro digestibility, polyethylene glycol (PEG) was used as a tannin binding agent. Both ensiled and dried GTB contained 31.9 to 32.6% of crude protein (CP) on a dry matter (DM) basis. Phenolics and tannins in soybean meal and alfalfa hay were low or not detected, but they were high in both ensiled and dried GTB (7.3-10.1% DM as total extractable tannins). In vitro protein digestibility in the rumen ranked: soybean meal > alfalfa hay cube > ensiled GTB = dried GTB. The protein digestibility post-ruminally of these feedstuffs showed a similar trend to that in the rumen, but the digestibility of ensiled GTB was significantly higher than that of dried GTB. Addition of PEG improved the in vitro protein digestibility of both kinds of GTB in the rumen and post-ruminally, indicating that tannins suppressed the potential protein digestibility of GTB. The increased protein digestibility by PEG addition was not significantly different between ensiled and dried GTB in the rumen, but the percentage increment of ensiled GTB was higher than dried GTB post-ruminally. In the in vivo digestibility trial, ensiled and dried GTB were offered to goats as partial substitutes for soybean meal and alfalfa hay cubes. Offering both GTB to goats as 5-10% on a DM basis did not affect nutrient digestibility, ruminal pH, volatile fatty acids, and ammonia concentration. However, the eating time of the GTB-incorporated diet was longer than that of the basal diet. It took 1.4 and 1.6 times longer than the control diet, to eat the diet completely when GTB silage was offered at 5 and 10% levels, respectively, of the total diet. These results show that ensiled and dried GTB are useful as partial substitutes for soybean meal and alfalfa hay cubes for goats with respect to nutritive value. Because of lessened palatability, it is recommended that GTB be incorporated into the diet at 5% on a DM basis.