三种支链氨基酸对小麦秸秆瘤胃体外发酵特性的影响

Effects of three branched chain amino acids on in vitro fermentation characteristics of wheat straw rumen

试验旨在评估3种支链氨基酸(缬氨酸、亮氨酸和异亮氨酸)对小麦秸秆体外瘤胃发酵性能的影响。将缬氨酸、亮氨酸和异亮氨酸分别以0、1、3、5和7 mol/L的浓度加入到瘤胃液中,厌氧培养72 h后,测定瘤胃液的pH、挥发性脂肪酸和氨氮浓度,以及干物质和中性洗涤纤维的降解性。结果:缬氨酸、亮氨酸或异亮氨酸的加入显著提高了挥发性脂肪酸总量(P<0.05),但无显著线性升高效应(P>0.05)。支链挥发性脂肪酸浓度随3种支链氨基酸添加水平的升高表现为显著线性升高(P<0.05)。随着缬氨酸和异亮氨酸的加入,乙酸和丙酸比值显著降低(P<0.05),丁酸浓度显著升高(P<0.05),同时随着亮氨酸添加水平的升高,丙酸和丁酸浓度显著降低(P<0.05)。与此同时,异丁酸浓度随着缬氨酸和亮氨酸添加水平的升高表现为显著线性降低(P<0.05),而异戊酸浓度随亮氨酸或异亮氨酸添加水平的升高表现为显著线性升高(P<0.05)。缬氨酸或异亮氨酸浓度在1 mmol/L时,对中性洗涤纤维的降解能力最大。结论:添加低浓度(1 mmo/L)的缬氨酸、亮氨酸或异亮氨酸,可使小麦秸秆的体外发酵产生较高的挥发性脂肪酸。

The experiment was conducted to evaluate the effects of three branched amino acids(valine,leucine and isoleucine)on rumen fermentation performance of wheat straws in vitro.Valine,leucine and isoleucine were added to rumen fluid at concentrations of 0,1,3,5 and 7 mol/L,respectively.After 72 h of anaerobic culture,the pH,volatile fatty acid and ammonia nitrogen concentrations,as well as the degradability of dry matter and neutral detergent fiber in rumen fluid were determined.Results:the addition of valine,leucine or isoleucine significantly increased the total volatile fatty acid(P<0.05),but there was no significant linear increase effect(P>0.05).The concentration of branching-chain volatile fatty acids increased linearly with the addition of three kinds of branching-chain amino acids(P<0.05).With the addition of valine and isoleucine,the ratio of acetic acid to propionic acid decreased significantly(P<0.05),and the butyric acid concentration increased significantly(P<0.05).Meanwhile,with the addition of leucine,the concentration of propionic acid and butyric acid decreased significantly(P<0.05).At the same time,the concentration of isobutyric acid decreased linearly with the increase of the addition of valine and leucine(P<0.05),while the concentration of isovaleric acid increased linearly with the increase of the addition of leucine or isoleucine(P<0.05).When the concentration of valine or isoleucine is 1 mmol/L,the degradation capacity of neutral detergent fiber is the greatest.Conclusion:adding low concentration(1 mmo/L)of valine,leucine or isoleucine can produce higher volatile fatty acids in vitro fermentation of wheat straw.