Effect of foliar selenium application on fermentation, nutrition and microbial community changes in semidry alfalfa silage

Abstract Selenium (Se) is an essential trace element in living systems. In this research, we applied a spray of 50mg/kg sodium selenite on alfalfa (Medicago sativa L.) at different stages (squaring, initial flowering, and full blooming stages). After 0, 1, 3, 7, and 45 days of ensiling, we assessed the fermentation, nutritional quality, and microbial community of alfalfa. Our findings indicate that the addition of Se led to the increase of crude protein (CP), ammonia-N and selenium content, and the decrease of pH, acid detergent fibre (ADF), neutral detergent fibre (NDF). As ensiling fermentation went on, the relative abundance of Lactobacillus in the treatment group was significantly higher than control group (3.76% vs 42.44%), and the number of bacteria decreased gradually. In conclusion, Se help to improve the silage quality and altered the bacterial community. This study provides valuable insights for the investigation of selenium-enriched alfalfa in semidry silage.