Effect of different levels of concentrate on ruminal microorganisms and rumen fermentation in Nellore steers
Effect of different levels of concentrate on ruminal microorganisms and rumen fermentation in Nellore steers
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DOI：
10.1080/1745039x.2015.1117562
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发表时间：
2016-01-02
影响因子：
2
通讯作者：
Berchielli, Telma T.
中科院分区：
文献类型：
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作者：
Granja-Salcedo, Yury T.;Ribeiro Junior, Carlos S.;Berchielli, Telma T.
本试验旨在研究不同精料水平对肉牛采食量、消化率、瘤胃发酵和微生物区系的影响。采用4 × 4拉丁方双设计试验，对8头装有瘤胃套管的Nellore阉牛进行试验。日粮处理由四种不同比例的精粗饲料组成：干物质30：70、40：60、60：40和80：20%，分别得到日粮30、40、60和80。粗饲料为玉米青贮，精饲料由玉米、豆粕和尿素组成。有机物和粗蛋白质的表观消化率与精料比例呈线性相关（p=0.01），但精料水平的提高不影响纤维的消化率。在饲喂饲料80的动物中观察到最低的瘤胃pH值，从饲喂后6小时起保持低于pH 6.0，而在其他饲料中，在饲喂后12小时之前瘤胃pH值不低于6.0。饲喂日粮80后，瘤胃中的氨浓度显著最高。较高的日粮精料水平导致丙酸浓度线性增加，乙酸与丙酸的比例线性降低（p
The aim of this study was to investigate the effect of different dietary levels of concentrate on feed intake, digestibility, ruminal fermentation and microbial population in steers. Eight Nellore steers fitted with ruminal cannulas were used in a double 4x4 Latin square design experiment. The dietary treatments consist of four different proportions of concentrate to roughage: 30:70, 40:60, 60:40 and 80:20% in the dry matter, resulting in Diets 30, 40, 60 and 80, respectively. The roughage was corn silage, and the concentrate was composed of corn, soybean meal and urea. Apparent digestibility of organic matter and crude protein showed a linear association with concentrate proportion (p=0.01), but the increased concentrate levels did not affect the digestibility of fibre. The lowest ruminal pH-values were observed in animals fed with Diet 80, remaining below pH 6.0 from 6h after feeding, while in the other diets, the ruminal pH was below 6.0 not before 12h after feeding. After feeding Diet 80, the ammonia concentration in the rumen was significantly the highest. Higher dietary concentrate levels resulted in a linear increase of propionic acid concentrations, a linear reduction of the ratio acetic acid to propionic acid (p