Feed characteristics and potential effects on rumen microbiome of ensiled seaweeds for dairy cows

• Published in: Book of Abstracts of the 72nd Annual Meeting of the European Federation of Animal Science
• Main Authors: Yen, Y., Weisbjerg, Martin Riis, Viswanath, K., Novoa-Garrido, M.
• Other Authors: Strandberg, E., Pinotti, L., Messori, S., Kenny, D., Lee, M., Hocquette, J.F., Cadavez, V.A.P., Millet, S., Evans, R., Veldkamp, T., Pastell, M., Pollott, G.
• Format: Conference Object
• Language: English
• Published: Wageningen Academic Publishers 2021
• Subjects: Norway; Northern Norway
• Online Access: https://pure.au.dk/portal/da/publications/feed-characteristics-and-potential-effects-on-rumen-microbiome-of-ensiled-seaweeds-for-dairy-cows(c8248117-8c50-4b02-9792-e32d5318cfdb).html; https://doi.org/10.3920/978-90-8686-918-3

Seaweed silage has potential to be an alternative feed ingredient for dairy cows. This study aims to evaluate the feed characteristics of ensiled seaweed, by performing chemical analysis and digestion examinations on Saccharina latissima and Alaria esculenta, preserved frozen or using various ensiling treatments (16 °C, 3 months) including: (1) NoA: no additives; (2) FA: 0.4% formic acids; (3) BI: lactic acid bacteria (LAB) inoculant; (4) BI30: LAB inoculant, and the biomass was prewilted to 30% dry matter (DM). Further, the microbiome of rumen fluid after 48 hours in vitro incubation with seaweed silages was analysed using16S rRNA sequencing. The seaweed was seeded at northern Norway (N68, E15) in autumn 2018, harvested in June 2019, and processed within 24 hours. Average DM content was low (9.4% without prewilting). The overall ash and crude protein contents were 243 and 111 g/kg DM, respectively. Without additives (NoA), silage pH failed to reach below 4.5. Acetate was the major volatile fatty acids found in all silages, while lactate was only detected in silages with LAB inoculant. The organic matter in vitro digestibility using rumen fluid (OMD) and indigestible NDF (iNDF) varied between species (P<0.001) and treatments (P<0.05). In FA treatments, the highest OMD (Alaria: 319 g/kg DM, Saccharina: 546 g/kg DM) and the lowest iNDF were observed (Alaria: 165 g/kg DM, Saccharina: 76.4 g/kg DM). The effective protein degradation at 5% passage rate (EPD5) and total protein digestibility using mobile bag were both low and not improved by silage treatments. The highest EPD5 was found in BI30 Saccharina (460 g/kg CP), while the highest digestible rumen bypass protein was found in frozen Saccharina (180 g/kg CP). Overall, S. latissima demonstrated higher digestibility and thus nutrients value comparing to A. esculenta. The microbiome analysis is still ongoing and expected to be available before the conference.