Enhancing Rumen Efficiency and Reducing Methane Emissions with South Sulawesi Seaweed as Feed Additives

Livestock methane emissions contribute significantly to global warming, necessitating the exploration of sustainable feed additives to enhance rumen efficiency and reduce environmental impact.This study investigates the potential of South Sulawesi seaweeds as feed additives to improve rumen fermentation efficiency and reduce methane emissions in ruminants.Seven seaweed species-Eucheuma cottoni, Eucheuma denticulatum, Caulerpa sp.(cultivated and non-cultivated), Gracilaria sp., Halimynea sp., and Sargassum sp.-were evaluated at inclusion levels of 0, 5, 10, and 15% in complete feed formulations using a factorial in vitro design.Key parameters such as dry matter degradation (DMD), organic matter degradation (OMD), ammonia concentration (NH), volatile fatty acids (VFAs), gas production, and methane (CH) output were measured.The highest DMD and OMD were observed with Sargassum sp. and Gracilaria sp. at the 15% inclusion level, suggesting enhanced nutrient utilization.Gracilaria sp. and Halimynea sp.produced the highest VFAs, indicating efficient fermentation.Methane production was significantly lower with Sargassum sp. and Eucheuma cottoni, likely due to bioactive compounds such as tannins and saponins.Non-cultivated species exhibited higher bioactive compound levels than cultivated ones, potentially influenced by environmental factors.These findings demonstrate that seaweed inclusion at 15% optimizes rumen efficiency and reduces methane emissions, presenting a sustainable strategy for improving livestock productivity while mitigating climate change impacts.