Sucrose concentration alters fermentation kinetics, products, and carbon fates during in vitro fermentation with mixed ruminal microbes
Sucrose concentration alters fermentation kinetics, products, and carbon fates during in vitro fermentation with mixed ruminal microbes
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DOI：
10.2527/jas.2006-014
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发表时间：
2007-06-01
影响因子：
3.3
通讯作者：
Weimer, P. J.
中科院分区：
文献类型：
--
作者：
Hall, M. B.;Weimer, P. J.
利用3种浓度的Sue和1种浓度的从稗草中分离的NDF在体外分批培养中与瘤胃接种物一起发酵，评价了蔗糖（Suc）浓度对发酵动力学和产物的影响。固定量的培养基和接种物是蛋白质来源，因此蛋白质：Suc随着Sue的增加而降低。在随机完全区组设计（n = 28）中，从48小时内的气体产生计算动力学，并且在时间设计（n = 84）中，在裂-裂图中，每4小时取样24小时，评价产物产率。以发酵瓶为实验单位。增加Sue使快速发酵（P < 0.01）和缓慢发酵（P < 0.01）组分的滞后时间增加，并有降低快速发酵组分产气速率的趋势（P = 0.07）。气体产量从缓慢的部分线性下降，增加苏（P = 0.02），这表明在NDF发酵减少。蔗糖是主要底物：！发酵8小时。微生物CP（MCP）生产的最大检测！发酵8小时。在检测到的MCP最大值，MCP生产线性增加（P = 0.02）和总有机酸（乳酸，乙酸，丙酸和丁酸的总和; mmol）趋于线性增加（P = 0.07）与增加苏。0和4 h的最大乳酸产量增加（P = 0.01），Sue的乳酸产量呈线性增加趋势（P = 0.09）。在检测到MCP最大值时，利用Sue C的产物（总有机酸、MCP、CO2、CH 4、糖原）中的C产量随着Sue增加而线性下降，总产物（P = 0.01）和有机酸（P = 0.01）呈线性下降，MCP呈下降趋势（P = 0.12）。这可能是随着Sue的增加，微生物的分解代谢效率增加的函数，如乳酸盐产量增加所证明的，或者C用于未测量的产物。从最低到最高的Sue含量，产物C产率分别为1.28、0.98和0.81。值> 1表示来自培养基的C的掺入，可能来自AA和肽。结果支持的前提，直接影响苏浓度和蛋白质：苏改变发酵产物的产量。底物浓度改变了发酵产物和动力学，可能是由于与运行条件的相互作用，建议明确定义底物和发酵条件，以确定结果如何整合到我们的反刍动物营养知识中。
Effects of sucrose (Suc) concentration on fermentation kinetics and products were evaluated using 3 concentrations of Sue, with 1 concentration of isolated NDF from Bermudagrass fermented together in batch culture in vitro with rumen inoculum. Fixed amounts of medium and inoculum were the protein sources, so protein:Suc decreased with increasing Sue. Kinetics were calculated from gas production over 48 h in a randomized complete block design (n = 28), and product yield was evaluated with sampling every 4 h for 24 h in a split-split plot in time design (n = 84). Fermentation vial was the experimental unit. Increasing Sue increased the lag time of rapidly (P < 0.01) and slowly fermented (P < 0.01) fractions and tended to decrease the rate of gas production from the rapid fraction (P = 0.07). Gas production from the slow fraction decreased linearly with increasing Sue (P = 0.02), suggesting a decrease in NDF fermentation. Sucrose was the predominant substrate at :! 8 h of fermentation. Maxima for microbial CP (MCP) production were detected at! 8 h of fermentation. At detected MCP maxima, MCP production increased linearly (P = 0.02) and total organic acids (sum of lactate, acetate, propionate, and butyrate; mmol) tended to increase linearly (P = 0.07) with increasing Sue. Maximum lactate production at 0 and 4 h increased (P = 0.01), and yield of lactate from Sue tended to increase, linearly (P = 0.09) with increasing Sue. At detected MCP maxima, yield of C in products (total organic acids, MCP, CO2, CH4, glycogen) from utilized Sue C declined linearly for total products (P = 0.01) and organic acids (P = 0.01) and tended to decline for MCP (P = 0.12) as Sue increased. This may be a function of increased catabolic inefficiency of microbes with increasing Sue, as evidenced by increasing yields of lactate, or the use of C for products not measured. Product Cyields were 1.28,0.98, and 0.81 from lowest to greatest Sue inclusion, respectively. Values > 1 indicate incorporation of C from the medium, likely from AA and peptides. The results support the premises that direct effects of Sue concentration and perhaps protein: Sue alter yields of fermentation products. That substrate concentration altered fermentation products and kinetics, possibly due to interactions with the run conditions, advises the clear definition of substrates and fermentation conditions to determine how the results integrate into our knowledge of ruminant nutrition.