Dietary secoisolariciresinol diglucoside crude extract improves growth through modulating rumen bacterial community and epithelial development in lambs

Abstract BACKGROUND Flaxseed lignans, types of polyphenolic compounds, primarily consist of secoisolariciresinol diglucoside (SDG). Natural plant extracts are becoming increasingly important as feed for ruminant animals. An underutilized plant bioactive component, SDG shows promising benefits for young ruminant production. The objective of this study was to assess the impact of SDG on rumen fermentation using an in vitro rumen simulation technology. Additionally, we tested the effects of SDG (0.20 g kg −1 body weight) on rumen development and production performance of lambs in a production setting. RESULTS The in vitro addition of 100 mg L −1 SDG demonstrated significant regulatory effects, with a notable decrease in the acetate/propionate ratio ( P < 0.05). Feeding trials revealed that SDG significantly increased average daily feed intake and average daily weight gain ( P < 0.05), and reduced the acetate/propionate ratio ( P < 0.05). This led to a significant increase in the relative abundance of Eubacterium ruminantium ( P = 0.038) and Butyrivibrio ( P = 0.002). Furthermore, it promoted rumen development and upregulated the relative expression of mRNA of Cyclin E1 and CDK2 in rumen epithelial cells ( P < 0.05). CONCLUSION The SDG extract optimizes the composition of rumen microbiota and the development of rumen epithelial cells, promoting the growth of pre‐weaning lambs. The SDG additive exhibits potential as a novel growth promoter for ruminant animals, offering a promising solution for sustainable livestock production. © 2024 Society of Chemical Industry.