Effects of Lavandula officinalis and Equisetum arvense dry extracts and isoquercitrin on the fermentation of diets varying in forage contents by rumen microorganisms in batch culture.

The short-term actions of Lavandula officinalis and Equisetum arvense dry extracts, and of isoquercitrin, flavonoid present in Equisetum arvense, on in vitro fermentation by rumen microbes were studied in batch culture. The orchard grass hay:barley ratios in the three experimental diets were 100:0, 75:25, 50:50 on a DM basis. The production rates of all volatile fatty acids except isobutyrate were strongly influenced by the composition of the diet and to a lesser extent, by plant extracts, with significant interactions between both factors. When hay was the only substrate, the addition of L. officinalis and E. arvense enhanced the fermentation rate by 50%, through an increased release of acetate and propionate. On the contrary, with the two other diets, the fermentation rate was strongly lowered by isoquercitrin. Gas outputs were not significantly influenced by plant extracts.