AUTHOR=Bao Yuhong , Yangzong Zhaxi , Yuan Zhenjie , Shi Ruizhi , Feng Ke , Xin Pengcheng , Song Tianzeng 

TITLE=The microbial communities and natural fermentation quality of ensiling oat (Avena sativa L.) harvest from different elevations on the Qinghai-Tibet Plateau

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1108890

DOI=10.3389/fmicb.2022.1108890

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Ensiling whole-crop oat (<italic>Avena sativa</italic> L.) has attracted a growing interest in the Qinghai-Tibet Plateau. The study aimed to investigate the microbial community and chemical composition of fresh and ensiling oat harvested from six different elevations of the Qinghai-Tibet Plateau.</p></sec><sec><title>Method</title><p>The oat (<italic>A. sativa</italic> L. cv. Qingyin No<italic>.</italic> 1) was planted in six different sites across Qinghai-Tibet Plateau (BM, Bomi County; BY, Bayi County; DZ, Dazi County; BR, Biru County; SC, Suo County; SN, Seni County), where the elevations were in the range of 2,800–4,500 m above sea level (a. s. l.). Oat was harvested at the milk stage and ensiled for 90 days.</p></sec><sec><title>Results</title><p>The highest crude protein (CP) and lowest water-soluble carbohydrate (WSC) were observed in fresh oat of SN and BM, respectively, however, no distinct gradient trend in WSC and CP concentrations along the elevation gradient. The lowest LAB counts in fresh oat from the highest elevational regions of SN. After 90 days of ensiling, the pH in all oat silages was lower than 4.2, and silages from SC and SN showed a lower pH and butyric acid concentration, and higher lactic acid (LA) concentration than silages of other regions. The oat silage from BR showed the lowest LA concentration and the highest pH. The bimodal distributions of fungal and bacterial richness in fresh oat along the elevation gradient were observed, while the elevation gradients did not affect the fungal Shannon index in fresh oat. <italic>Dioszegia</italic>, <italic>Cladosporium</italic>, and <italic>Vishniacozyma</italic> were the prevalent fungal genus in fresh oat, while <italic>Wickerhamomyces</italic>, <italic>Candida</italic>, and <italic>Saccharomyces</italic> dominated the fungal communities of silages. <italic>Wickerhamomyces</italic> and <italic>Candida</italic> were the dominant genera in oat silages from BM and SC, respectively. <italic>Erwinia</italic>, <italic>Paenibacillus</italic>, <italic>Pseudomonas</italic>, <italic>Leuconostoc</italic>, and <italic>Exiguobacterium</italic> dominated the bacterial community of fresh oat, while <italic>Lactobacillus</italic> and <italic>Kosakonia</italic> were the dominant bacterial genus in oat silages. <italic>Pantoea</italic> was the most dominant bacterial genus in fresh oat from low-elevational regions (BM, BY, and DZ). Oat from SN exhibited the best fermentation quality although fresh oat of SN hosted the lowest LAB counts, indicating that high-efficient LAB might be present in fresh oat sampled from high altitudes.</p></sec>