Effect of lactic acid bacteria isolated from Tibetan Plateau on silage fermentation quality of Elms nutans

Abstract:

Abstract:［Objective］ In order to detect the effect of lactic acid bacteria isolated from Tibetan Plateau on silage fermentation quality of Elms nutans．［Methods］ We used 3 isolated lactic acid bacteria with better growth at low temperatures of 10 and 15 ℃ at ensiling of Elymus nutans． Subsequently，effects of the selected lactic acid bacteria on fermentation profiles of Elymus nutans silages stored at 15 and 25 ℃ were evaluated by using the same species of commercial inoculants as the control．［Results］PP-6 isolated from Tibetan Plateau could ferment raffinose，lactose，sorbitol，melibiose and sucrose，and LS-5 could ferment cottonseed sugar，laetrile，rhamnose，lactose，sorbitol，xylose，arabinose，melibiose and sucrose，but the same species of commercial strains could not use these sugars． Inoculation of these three strains into Elymus nutans at 15 and 25 ℃ ensiled for 50 d，we found that LS-5 significantly reduced silage pH，propionic acid concentration and ratio of ammonia nitrogen/total nitrogen at 15 ℃ (P＜0.05)，salvaged more water-soluble carbohydrate and crude protein; Application of LP-2 and PP-6 as a combined inoculant to Elymus nutans significantly improved lactic acid concentration (P＜0.05)，resulting in a lower ratio of ammonia nitrogen/total nitrogen，saved more crude protein and significantly reduced neutral detergent fiber content (P＜0. 05) as compared with the commercial strains．［Conclusion］The three isolated strains can improve silage quality of Elymus nutans growing on the Qinghai-Tibetan Plateau at low temperature，but these strains have no obvious advantages at 25 ℃ in comparison with the commercial inoculants.