在体外模拟瘤胃发酵条件下N-乙酰-DL-蛋氨酸稳定性的研究

Study on the stability of N-Acetyl-DL-Methionine in vitro simulating rumen fermentation system

通过两个试验,研究在体外模拟瘤胃发酵条件下N-乙酰-DL-蛋氨酸的降解率。试验1:N-乙酰-DL-蛋氨酸在pH值6.5、温度为39℃的缓冲液中孵育9h,其降解率为3.3%。试验2:运用瘤胃体外发酵技术研究N-乙酰-DL-蛋氨酸不同添加量对pH值、氨态氮、微生物蛋白动态变化的影响。结果表明,添加0.4、0.6gN-乙酰-DL-蛋氨酸发酵3～6h,均能够显著降低体系的pH值;添加0.6gN-乙酰-DL-蛋氨酸发酵12h能够显著提高氨态氮的浓度;N-乙酰-DL-蛋氨酸在发酵过程中不影响微生物蛋白产量。以上结果显示,N-乙酰-DL-蛋氨酸在体外模拟瘤胃发酵的条件下可以稳定存在。

Two experiments are conducted in this paper to study the degradation rates of N-Acetyl-DL- Methionine in vitro simulating rumen fermentation system. In Exp.1, under the conditions of pH 6.5 and 39 ℃,the degradation rate is about 3.3% after 9 hours of culture. In Exp.2, the kinetic effects of gradient doses of N-Acetyl-DL-Methionine were carried out on pH value and concentrations of ammonia nitrogen and microbial protein. The results indicated： that pH value is reduced significantly by the dosage of 0.4 and 0.6 g respectively after adding 3-6 hours; that the concentrations of ammonia nitrogen is increased significantly by the dosage of 0.6 g after fermenting 12 hours. During the fermentation, the microbial protein was not affected. It is inferred that N-Acetyl-DL-Methionine is stable under the condition of in vitro simulating rumen fermentation system.