Abstract
OBJECTIVE: Information regarding the vitamin content of silage is limited. This study investigated the changes in the vitamin content of alfalfa and Chinese leymus silages with or without a lactic acid bacterial inoculant. METHODS: Alfalfa at the early flowering stage and Chinese leymus at the full-bloom stage were harvested. The treatments for each forage type were control (deionized water only) and 1×106 colony-forming units (cfu) Lactobacillus plantarum (LP) g-1 FM. After 45 d ensiling, all silages were sampled for evaluating the vitamin content, fermentation quality and chemical composition. RESULTS: The LP inoculant decreased the pH and ammonia nitrogen content of the alfalfa and Chinese leymus silages and significantly (p < 0.05) increased the lactic acid, acetic acid, propionic acid content and Flieg`s points. Prior to ensiling, the levels of five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine) and α-tocopherol in alfalfa were significantly higher than those in Chinese leymus (p < 0.01). Ensiling decreased the levels of the five B-group vitamins in both alfalfa and Chinese leymus while increasing the α-tocopherol content of Chinese leymus. The thiamin, riboflavin, niacin and pantothenic acid levels in the LP-treated silage were significantly (p < 0.05) lower than those in the untreated silage for both forages. The α-tocopherol content in the LP-treated alfalfa silage was significantly (p < 0.05) higher than that in the untreated alfalfa silage. There was no significant (p > 0.05) difference in pyridoxine content between the untreated and LP-treated silages for both forages. CONCLUSION: With or without LP inoculation, the levels of the five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine) in alfalfa and Chinese leymus decreased after 45 days of ensiling, while the α-tocopherol content of Chinese leymus increased. The LP inoculant improved the fermentation quality of both the alfalfa and Chinese leymus silages but increased the thiamin, riboflavin, niacin and pantothenic acid loss in the two forages after fermentation.