Effects of Quinoa Secondary Metabolites on In Vitro Fermentation and Gas Production

Livestock methane emissions are a significant source of greenhouse gases. The aim of this study was to investigate the secondary metabolites of different strains of silage quinoa and their impact on methane emissions from livestock farming. In this study, we evaluated the chemical composition, fermentation quality, secondary metabolite content, and in vitro gas production of eight quinoa lines, 093, 137, 231, 238, 565, 666, 770, and 811, grown in saline and alkaline areas of the Yellow River Delta. The results showed that crude protein, EE, and crude ash content ranged from 8.84% to 10.69%, 1.98% to 2.38%, and 17.00% to 23.14%, respectively. The acidic and neutral detergent fiber content of these eight quinoa varieties ranged from 49.31% to 61.91% and 33.29% to 37.31%, respectively. Line 093 had the highest total saponin content, while Line 231 exhibited the highest flavonoid content. Methane yield was significantly and negatively correlated with tannin, saponin, and flavonoid content, whereas carbon dioxide yield showed a positive correlation with saponin and flavonoid content. Among all lines, 770 and 811 demonstrated the lowest methane production, indicating strong in vitro inhibition of methanogenesis. These findings suggest that feeding quinoa silage to ruminants has the potential to reduce greenhouse gas emissions.