发生大量的蛋白水解,游离氨基酸可以通过在stylo(Stylosanthesguianensis)青贮期间脱羧降解为生物胺。青贮饲料中的高生物胺浓度对反刍动物的健康有害。这项工作的目的是(1)分析生物胺和氨基酸的浓度,细菌组成,和自然发酵型青贮饲料的发酵概况,(2)摸索甲酸或糖添加剂对这些青贮参数的影响,(3)进一步揭示了青贮胺与发酵参数之间的相关性,氨基酸,和细菌。用蒸馏水(对照)处理新鲜切碎的铁柱,甲酸(4mL/kg),和糖(20g/kg)并发酵28天。结果表明,腐胺(321毫克/千克干物质),尸胺(384毫克/千克干物质),发酵28天后,酪胺(127mg/kg干物质)的浓度迅速增加,并在对照青贮饲料中占主导地位。在青贮时施用甲酸和糖,尤其是酸化剂,显著减少腐胺,尸体,酪胺,和总生物胺浓度与对照处理相比(p<0.0001)。巴布氏杆菌,对照青贮饲料中的主要细菌是黄牛和副肠球菌,与对照处理相比,两种添加剂的应用显着降低了它们的相对丰度(p<0.001)。相关分析表明,腐胺,尸体,酪胺与pH呈正相关,丁酸,非蛋白氮,氨氮(p<0.01)。这些胺也与巴布丁酸梭菌有显著的相关性,西巴里亚和副肠杆菌(p<0.001)。腐胺,尸体,酪胺是主要的生物胺,巴布林是自然发酵青贮中的主要不良细菌。C.巴布利丁酸,西巴氏杆菌和副肠氏杆菌与腐胺呈正相关,尸体,和酪胺的形成。甲酸或糖的应用显着减少了不良细菌种群,并改善了发酵和卫生质量。这些发现为进一步阐明发酵过程中主要生物胺形成的微生物机制奠定了基础。
Substantial proteolysis occurs and free amino acids can be degraded to biogenic amines by decarboxylation during stylo (Stylosanthes guianensis) ensiling. High biogenic amine concentrations in silage are harmful to the health of ruminant animals. The purposes of this work were to (1) analyze the biogenic amines and amino acids concentrations, bacterial composition, and fermentation profile of spontaneously fermented stylo silage, (2) explore the effect of formic acid or sugar additive on these silage parameters, and (3) further reveal the correlations between silage amines and fermentation parameters, amino acids, and bacteria. Freshly chopped stylo was treated with distilled water (control), formic acid (4 mL/kg), and sugar (20 g/kg) and fermented for 28 days. The results indicated that putrescine (321 mg/kg dry matter),
cadaverine (384 mg/kg dry matter), and tyramine (127 mg/kg dry matter) rapidly increased in concentration and become predominant in the control silage after 28 days of fermentation. Applying formic acid and sugar at ensiling, especially the acidifier, significantly decreased putrescine,
cadaverine, tyramine, and total biogenic amine concentrations compared with the control treatment (p < 0.0001). Clostridium pabulibutyricum, Weissella cibaria and W. paramesenteroides were the predominant bacteria in the control silage, and the application of both additives remarkably lowered their relative abundance in comparison with the control treatment (p < 0.001). Correlation analysis showed that putrescine,
cadaverine, and tyramine were positively related to pH, butyric acid, non-protein nitrogen, and ammonia nitrogen (p < 0.01). These amines also had significant correlations with C. pabulibutyricum, W. cibaria and W. paramesenteroides (p < 0.001). Putrescine,
cadaverine, and tyramine were the main biogenic amines and C. pabulibutyricum was the predominant undesirable bacterium in naturally fermented stylo silage. C. pabulibutyricum, W. cibaria and W. paramesenteroides were positively related to putrescine,
cadaverine, and tyramine formation. The application of formic acid or sugar significantly reduced the undesirable bacterial population and improved the fermentation and hygienic quality of the stylo silage. These findings lay the foundation for further elucidating the microbial mechanism underlying the main biogenic amine formation during fermentation of stylo silage.