EFFECT OF DIRECT-FED MICROBIALS ON RUMEN MICROBIAL FERMENTATION
EFFECT OF DIRECT-FED MICROBIALS ON RUMEN MICROBIAL FERMENTATION
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DOI：
10.3168/jds.s0022-0302(92)77932-6
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发表时间：
1992-06-01
影响因子：
3.5
通讯作者：
NISBET, DJ
中科院分区：
文献类型：
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作者：
MARTIN, SA;NISBET, DJ
添加到反刍动物饲料中的非细菌、直接喂养的微生物通常由米曲霉发酵提取物或酿酒酵母培养物组成，或两者兼而有之。关于直接饲喂微生物对反刍动物饲料利用和生产性能的影响，体内研究结果不一。一些研究表明体重增加，产奶量和饲料成分的全消化道消化率增加，但其他研究表明直接喂养微生物对这些参数的影响很小。在混合瘤胃微生物的体外研究中，直接饲喂微生物的效果也不一致。一些研究人员观察到，直接饲喂的微生物增加了瘤胃中纤维素分解细菌的数量，并刺激了一些发酵终产物的模具生产。这表明直接饲养的微生物可能为瘤胃微生物提供了生长因子。然而，其他研究人员报告说，直接饲喂的微生物对体外纤维消化没有影响。近年来的研究表明，瘤胃优势菌反刍单胞菌在乳酸培养基中的生长以及瘤胃全细胞对乳酸的吸收。米曲霉发酵提取物和酿酒酵母培养物显著提高了反刍动物的食用量。此外，这两种产品都增加了乙酸、丙酸、琥珀酸的产量，总VFA和细胞产量（每摩尔乳酸的细胞克数）。因此，这些直接喂养的微生物似乎提供了可溶性因子，刺激了Sel对乳酸的利用。ruminantium。有证据表明，米曲霉发酵提取物和酿酒酵母培养物的苹果酸含量可能参与了这种刺激。
Nonbacterial, direct-fed microbials added to ruminant diets generally consist of Aspergillus oryzae fermentation extract, or Saccharomyces cerevisiae cultures, or both. Results from in vivo research have been variable regarding effects of direct-fed microbials on ruminant feedstuff utilization and performance. Some research has shown increased weight gains, milk production, and total tract digestibility of feed components, but others have shown little influence of direct-fed microbials on these parameters. In vitro research with mixed ruminal microorganisms likewise has been inconsistent regarding the effects of direct-fed microbials. Several researchers observed that direct-fed microbials increased cellulolytic bacterial numbers in the rumen and stimulated die production of some fermentation end products. This suggests that direct-fed microbials may be providing growth factors for the ruminal microbes. However, other researchers have reported no effect of direct-fed microbials on in vitro fiber digestion. Recent research demonstrated that growth Of the predominant ruminal bacterium Selenomonas ruminantium in lactate medium as well as lactate uptake by whole cells of Sel. ruminantium were markedly increased by an A. oryzae fermentation extract and an S. cerevisiae culture. In addition, both products increased the production of acetate, propionate, succinate, total VFA, and cell yield (grams of cells per mole of lactate). Therefore, it appears that these direct-fed microbials provide soluble factors that stimulate lactate utilization by Sel. ruminantium. Evidence is presented indicating that the malate content of the A. oryzae fermentation extract and S. cerevisiae culture may be involved in this stimulation.