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草业学报 ›› 2022, Vol. 31 ›› Issue (7): 76-84.DOI: 10.11686/cyxb2021245

• 研究论文 • 上一篇    下一篇

晾晒、添加物及不同温度对象草青贮发酵品质和微生物的影响

田静(), 尹祥, 樊杨, 李鑫琴, 张建国()   

  1. 华南农业大学南方草业中心,广东 广州 510642
  • 收稿日期:2021-06-17 修回日期:2021-09-16 出版日期:2022-07-20 发布日期:2022-06-01
  • 通讯作者: 张建国
  • 作者简介:E-mail: zhangjg@scau.edu.cn
    田静(1994-),女,安徽阜阳人,在读博士。E-mail: 1803155313@qq.com
  • 基金资助:
    国家自然科学基金项目(31971764);广东省现代草牧业(羊)产业技术体系(2019KJ127)

Effects of wilting and additives on the fermentation quality and dominant microbial genera in Napier grass silage at different temperatures

Jing TIAN(), Xiang YIN, Yang FAN, Xin-qin LI, Jian-guo ZHANG()   

  1. South Pratacultural Research Center,South China Agricultural University,Guangzhou 510642,China
  • Received:2021-06-17 Revised:2021-09-16 Online:2022-07-20 Published:2022-06-01
  • Contact: Jian-guo ZHANG

摘要:

华南地区气候潮湿多雨,象草收获时水分含量高,单独青贮发酵品质较差。通过晾晒(水分含量由83.19%降至75.11%)、添加10%玉米粉或2%蔗糖,探究象草在不同温度(20、30和40 ℃)下青贮的发酵特性和微生物组成。研究结果表明:温度对象草各处理的青贮饲料的发酵品质有显著影响。晾晒后原材料的水溶性碳水化合物含量显著降低,青贮后发酵品质变差,尤其在30 ℃,pH达到5.85,乳酸含量只有1.56% DM,乙酸含量为2.10% DM,NH3-N含量高达25.09% TN。对照和添加物处理的青贮饲料均随青贮温度升高,乙酸含量增加。晾晒后在20和30 ℃时青贮,产气量显著高于40 ℃或未晾晒处理。此外,象草青贮前的细菌多样性较丰富,青贮后主要是肠杆菌属和乳球菌属,尤其是20 ℃青贮的相对丰度较高,且晾晒处理在20和30 ℃青贮肠球菌属的相对丰度高于40 ℃。因此,在华南地区,象草原料中添加玉米粉或蔗糖可以降低环境温度对象草青贮发酵品质的不良影响,阴湿条件下晾晒未发挥积极效果。

关键词: 象草, 青贮, 晾晒, 贮藏温度, 细菌多样性

Abstract:

Due to the moist, humid climate in South China, the moisture content of harvested Napier grass is high, and the fermentation quality of silage, when ensiled directly, is poor. In this study, Napier grass was wilted (moisture content decreased to 75.11% from 83.19%) and 10% corn flour or 2% sucrose was added, to explore the fermentation characteristics and microbial fermentative community during ensiling at different temperatures (20, 30 and 40 ℃) for 60 days. It was found that temperature had significant effects on the fermentation quality of Napier grass silages. Wilting decreased the water-soluble carbohydrate content of pre-ensiled Napier grass and the fermentation quality of silages, especially when ensiled at 30 ℃, as indicated by a high pH of 5.85, low lactic acid content of 1.56% DM, an acetic acid content of 2.10% DM, and an NH3-N content of 25.09% TN. The acetic acid production of both the untreated Control and silages with additives increased with increase in ensiling temperature. The gas production of wilted silages ensiled at 20 and 30 ℃ was significantly higher than that at 40 ℃ or for unwilted silages. In addition, the bacterial diversity of Napier grass before ensiling was higher than its silage. After ensiling, the microorganisms found on Napier grass were dominated by the genera Enterobacter and Lactococcus, especially when ensiled at 20 ℃. The relative abundance of Enterococcus in wilted silage at 20 and 30 ℃ was higher than at 40 ℃. In summary, adding corn flour and sucrose can decrease the negative influence of environmental temperature while wilting under humid conditions did not have a positive effect on the fermentation quality of Napier grass silage in South China.

Key words: Napier grass, silage, wilting, storage temperature, bacterial diversity