Lactic acid bacterial inoculant effects on the vitamin content of alfalfa and Chinese leymus silage

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 fullbloom stage were harvested. The treatments for each forage type were control (deionized water only) and 1×106 colonyforming units Lactobacillus plantarum (LP)/g fresh matter. After 45 days of ensiling, all silages were sampled for evaluating the vitamin content, fermentation quality and chemical composition. Results: The LP inoculant decreased the pH value and ammonia nitrogen content of the alfalfa and Chinese leymus silages and significantly (p<0.05) increased the lactic acid, acetic acid concentrations and Flieg’s points. Prior to ensiling, the levels of five Bgroup vitamins (thiamin, riboflavin, niacin, pantothenic acid, and pyridoxine) and αtocopherol in alfalfa were significantly (p<0.01) higher than those in Chinese leymus. Ensiling decreased the levels of the five Bgroup vitamins in both alfalfa and Chinese leymus while increasing the αtocopherol content of Chinese leymus. The thiamin, riboflavin, niacin and pantothenic acid levels in the LPtreated silage were significantly (p<0.05) lower than those in the untreated silage for the alfalfa and Chinese leymus. The αtocopherol content in the LPtreated 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 LPtreated silages for both forages. Conclusion: With or without LP inoculation, the levels of the five Bgroup vitamins (thiamin, riboflavin, niacin, pantothenic acid, and pyridoxine) in alfalfa and Chinese leymus decreased after 45 days of ensiling, while the αtocopherol 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.