Li Ting, OuYang Kehui, Qiu Qinghua, Zhao Xianghui, Liu Chanjuan
Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang Jiangxi 330045, China.
Anim Biosci. 2024 Oct;37(10):1738-1750. doi: 10.5713/ab.24.0026. Epub 2024 May 7.
This study investigated the impact of Aspergillus niger lysing polysaccharide monooxygenase (AnLPMO) on in vitro rumen microbial fermentation of rice straw.
AnLPMO was heterologously expressed in Escherichia coli. Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy analyzed the surface structure of rice straw after AnLPMO treatment. Two in vitro experiments, coupled with 16S highthroughput sequencing and quantitative real-time polymerase chain reaction techniques, assessed the influence of AnLPMO on rumen microbial fermentation of rice straw.
AnLPMO exhibited peak activity at 40°C and pH 6.5, with a preference for rice straw xylan hydrolysis, followed by Avicel. AnLPMO application led to the fractional removal of cellulose and hemicelluloses and a notable reduction in the levels of carbon elements and C-C groups present on the surface of rice straw. Compared to the control (no AnLPMO), supplementing AnLPMO at 1.1 to 2.0 U significantly enhanced in vitro digestibility of dry matter (IVDMD, p<0.01), total gas production (p<0.01), and concentrations of total volatile fatty acids (VFA, p<0.01), acetate (p<0.01), and ammonia-N (p<0.01). Particularly, the 1.4 U AnLPMO group showed a 14.8% increase in IVDMD. In the second experiment, compared to deactivated AnLPMO (1.4 U), supplementing bioactive AnLPMO at 1.4 U increased IVDMD (p = 0.01), total gas production (p = 0.04), and concentrations of total VFA (p<0.01), propionate (p<0.01), and ammonia-N (p<0.01), with a limited 9.6% increase in IVDMD. Supplementing AnLPMO stimulated the growth of ruminal bacterial taxa facilitating fiber degradation, including Proteobacteria, Spirochaetes, Succinivibrio, Rikenellaceae_RC9_ Gut_Group, Prevotelaceae_UCG-003, Desulfovibrio, Fibrobacter succinogenes, Ruminococcus albus, R. flavefaciens, Prevotella bryantii, P. ruminicola, and Treponema bryantii.
These findings highlight AnLPMO's potential as a feed additive for improving rice straw utilization in ruminant production.
本研究调查了黑曲霉裂解多糖单加氧酶（AnLPMO）对稻草体外瘤胃微生物发酵的影响。
AnLPMO在大肠杆菌中进行异源表达。采用傅里叶变换红外光谱和X射线光电子能谱分析AnLPMO处理后稻草的表面结构。通过两个体外实验，结合16S高通量测序和定量实时聚合酶链反应技术，评估AnLPMO对稻草瘤胃微生物发酵的影响。
AnLPMO在40°C和pH 6.5时表现出峰值活性，优先水解稻草木聚糖，其次是微晶纤维素。AnLPMO的应用导致纤维素和半纤维素部分去除，稻草表面碳元素和C-C基团水平显著降低。与对照（不添加AnLPMO）相比，添加1.1至2.0 U的AnLPMO显著提高了体外干物质消化率（IVDMD，p<0.01）、总产气量（p<0.01）以及总挥发性脂肪酸（VFA，p<0.01）、乙酸（p<0.01）和氨氮（p<0.01）的浓度。特别是，1.4 U AnLPMO组的IVDMD提高了14.8%。在第二个实验中，与失活的AnLPMO（1.4 U）相比，添加1.4 U的生物活性AnLPMO提高了IVDMD（p = 0.01）、总产气量（p = 0.04）以及总VFA（p<0.01）、丙酸（p<0.01）和氨氮（p<0.01）的浓度，IVDMD有限增加了9.6%。添加AnLPMO刺激了瘤胃中促进纤维降解的细菌类群的生长，包括变形菌门、螺旋体门、琥珀酸弧菌属、理研菌科_RC9_肠道菌群、普雷沃氏菌科_UCG-003、脱硫弧菌属、产琥珀酸丝状杆菌、白色瘤胃球菌、黄化瘤胃球菌、布氏普雷沃氏菌、瘤胃普雷沃氏菌和布氏密螺旋体。
这些发现突出了AnLPMO作为饲料添加剂在提高反刍动物生产中稻草利用率方面的潜力。
