A review: Effects of saponin on ruminal fermentation, nutrient utilization, body weight and methane mitigation in ruminants

Abstract

Saponins are plant secondary compounds found in shrubs and trees. While saponins derived from plants have been employed to regulate methanogenesis conducted by archaeal methanogens in the rumen, the outcomes have shown variability. Saponins divided into two groups based on their structure: triterpene and steroid glycosides. Saponins offer benefits like membrane-permeabilizing, immunostimulant, and hypocholesterolaemic properties, some saponin-containing plants can be toxic. In animal nutrition, saponins play both positive as well as negative roles. They can enhance ruminal fermentation by acting as defaunating agents, improving N-use efficiency, Reduces methane emission and potentially boosting animal performance by affecting nutrient utilization and their body weights. Moreover, studies have indicated that saponins can hinder protein digestion in the gut by interacting with cholesterol in the cell membrane, leading to cell rupture and selective elimination of ruminal protozoa. This mechanism is believed to enhance nitrogen utilization efficiency and potentially contribute to increase in animal performance. Saponin also possess antimicrobial activities and manipulating the microbial ecosystem. Overall, saponins have diverse effects, making their impact on animal health and performance complex. In conclusion, saponin proves efficacious in reducing In vivo enteric methane emissions from ruminants while concurrently improving nutrient digestibility, with an optimal utilization level not surpassing 0.5- 1% of dry matter.