Ensiling sorghum with unsalable pumpkin improves feed digestibility with minimal influence on the rumen microbial population using the rumen simulation technique

• Published in: Applied microbiology and biotechnology Vol. 105; no. 8; pp. 3289 - 3300
• Main Authors: Forwood, Daniel L., Caro, Eleonora, Holman, Devin B., Meale, Sarah J., Chaves, Alex V.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2021; Springer; Springer Nature B.V
• Subjects: Acetic acid; Analysis; Animal Feed - analysis; Animals; Biomedical and Life Sciences; Biotechnology; Cucurbita; Diet; Digestibility; Digestion; Dry matter; Fatty acids; Fermentation; Fungi; Gas production; Genomics; Life Sciences; Microbial activity; Microbial Genetics and Genomics; Microbial populations; Microbiology; Microorganisms; Oil and gas production; Propionic acid; Proteomics; Pumpkins; Relative abundance; RNA, Ribosomal, 16S - genetics; RNA, Ribosomal, 16S - metabolism; rRNA 16S; Rumen; Rumen - metabolism; Rumen fermentation; Silage; Sorghum; Transcriptomics; Volatile fatty acids; Switzerland; Microbial diversity; Rumen fermentation; Unsalable vegetables; RUSITEC
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-021-11220-2

This study aimed to determine the influence of sorghum ensiled with unsalable pumpkin at 20 or 40% dry matter (DM) basis on rumen fermentation characteristics and rumen microbial communities using the rumen simulation technique (RUSITEC). The experiment used a completely randomised design including silages comprising (1) 100% sorghum; (2) 80% sorghum + 20% DM pumpkin; or (3) 60% sorghum + 40% DM pumpkin. Each RUSITEC run ( n = 2) was 15 d long, including 6 d of adaptation and 9 d of sampling. Dry matter digestibility (DMD) was measured on d 8 and 10–13. Gas production was measured daily, whereas methane and volatile fatty acids (VFA) production were measured from d 7–15. Solid-associated microbes (SAM) were collected on d 5, 10 and 15, whereas liquid-associated microbes (LAM) were collected after 15-d incubation. The V4 region of the 16S rRNA gene and the ITS1 region were sequenced to identify archaeal, bacterial and fungal communities. Ensiling 40% DM pumpkin with sorghum increased DMD and decreased the ratio of acetate to propionate ( P ≤ 0.01). Both bacterial SAM and LAM communities were dominated by Megasphaera , and had the highest relative abundance ( P = 0.03) with 40% DM pumpkin after 5 d incubation in the SAM community, while species of the Aspergillus genus dominated fungal SAM and LAM communities with 20 or 40% DM unsalable pumpkin. Therefore, ensiling up to 40% DM unsalable pumpkin with sorghum produces a high-quality ruminant feed with minimal influence on the rumen microbial population. Key points • Including 40% DM unsalable pumpkin decreased acetate:propionate • Ensiling unsalable pumpkin with sorghum increases digestibility in a RUSITEC • Rumen microbial communities were slightly influenced by unsalable pumpkin inclusion