Effect of Scrophularia striata extract on efficiency of degradation, concentration of phenolic and flavonoid compounds and antioxidant activity in ruminal fluid using a rumen simulation technique (RUSITEC)

Extract of Scrophularia striata (ES) was tested as a feed additive for improving the efficiency of ruminal degradation of nutrients, concentration of total phenolic and flavonoid compounds and antioxidant activity using the rumen simulation technique (RUSITEC). Twelve fermentation units (vessels) were set up for 2 experimental runs each lasting 10 d wherein the last 5 days served for sampling. Treated vessels were supplied with no additive (Control), 10 mg/d monensin (Monensin), and 480 and 960 mg/d of ES, respectively. Both levels of ES and monensin decreased methane production expressed per gram nutrients degraded (P<0.05). Production of total volatile fatty acid per gram DM and organic matter degraded was higher in ES treatments in comparison with control and Monensin (P<0.05). The ammonia production expressed per gram CP degraded was lower than control only in the high level of ES supplementation (P<0.05). The latter treatment also resulted in the highest concentration of total flavonoid, phenol lic compounds and antioxidant activity compared to other treatments (P<0.05). Based on the present results, ES could be considered as an alternative to antibiotic for improving the efficiency of degradation, increasing ruminal antioxidant activity and decreasing methane production.