Li Mao, Lv Renlong, Zhang Lidong, Zi Xuejuan, Zhou Hanlin, Tang Jun
Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China.
Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, Key Laboratory of Germplasm Resources of Tropical Special Ornamental Plants of Hainan Province, College of Forestry, Hainan University, Danzhou, China.
Front Microbiol. 2021 May 26;12:670764. doi: 10.3389/fmicb.2021.670764. eCollection 2021.
The safe and effective storage of forage are very important. As an important storage method, ensiling can keep fresh forage for a long time with less nutritional loss. Melatonin has antioxidant and bacteriostasis, usually used as a natural preservative. The influence of melatonin on silage microbial or fermentation quality has not been clarified. In the present study, we aimed to clarify whether melatonin affected stylo () silage quality via microbiota and metabolites. Melatonin addition significantly improved the silage fermentation quality, including the increased contents of lactic acid and total acid (244.18-255.81% and 63.95-78.97%, respectively), as well as the decreased in pH and butyric acid content compare with control group. Moreover, 16S rRNA sequencing indicated that melatonin addition enhanced the silage microbial diversity indices (such as increase in Shannon indices but decrease in Simpson indices), and significantly shaped the composition of silage microbiota (such as increased abundances of , , , and , and decreased abundance of ). Melatonin addition also dramatically affected the metabolites of sylo silage, such as raised malonic acid and some amino acid metabolism(glycine, threonine, methionine and ornithine), while reduced nucleic acid metabolism(2-deoxyuridine and thymine) and carbon metabolism(allose and 2-deoxy-D-glucose). Collectively, our results confirmed that the lowest melatonin addition (5 mg/kg) could improve the fermentation quality, and the potential mechanisms might be associated with the microbiota and metabolites in stylo.
牧草的安全有效储存非常重要。作为一种重要的储存方法，青贮可以使新鲜牧草长时间保存且营养损失较少。褪黑素具有抗氧化和抑菌作用，通常用作天然防腐剂。褪黑素对青贮微生物或发酵品质的影响尚未明确。在本研究中，我们旨在阐明褪黑素是否通过微生物群和代谢产物影响柱花草青贮品质。添加褪黑素显著改善了青贮发酵品质，包括乳酸和总酸含量增加（分别增加244.18 - 255.81%和63.95 - 78.97%），与对照组相比，pH值和丁酸含量降低。此外，16S rRNA测序表明，添加褪黑素提高了青贮微生物多样性指数（如香农指数增加但辛普森指数降低），并显著塑造了青贮微生物群的组成（如 、 、 、 和 的丰度增加，而 的丰度降低）。添加褪黑素还显著影响了柱花草青贮的代谢产物，如丙二酸和一些氨基酸代谢（甘氨酸、苏氨酸、蛋氨酸和鸟氨酸）增加，而核酸代谢（2 - 脱氧尿苷和胸腺嘧啶）和碳代谢（阿洛糖和2 - 脱氧 - D - 葡萄糖）减少。总体而言，我们的结果证实，最低剂量的褪黑素添加量（5 mg/kg）可改善发酵品质，其潜在机制可能与柱花草中的微生物群和代谢产物有关。
