Evaluation of Conservation Characteristics and Aerobic Stability in Whole Crop Corn Silage Treated with Lactic Acid Bacteria and Artemisia Argyi

Whole crop corn silage (WCCS) has a high nutritional value and high overall economic efficiency, and is the most commonly used feed for ruminants. However, at the silage out feeding phase, the rise in temperature and relative humidity under aerobic conditions breeds the production of un-desirable microorganisms such as yeast and mold. In order to investigate the conservation char-acteristics and aerobic stability underlying the effects of additives in whole-crop corn silage (WCCS), a mixed silage was prepared by adding Lentilactobacillus (L.) buchneri (LB) and different proportions of Artemisia argyi (AA) during the milk-ripe stage of whole-crop corn (WCC).The study found that AA as an additive improved the fermentation quality and enhanced aerobic stability of WCCS, for which, the addition of 60% AA increased the lactic acid fermentation rate, decreased the relative abundance of harmful microorganisms and reduced the content of fungal toxins. Furthermore, we also discovered that the relative abundance of Candida within the 60% AA was the highest. Candida have the ability to convert WSC into organic acids and lower pH, thus improving the quality of silage. Particularly, in the metagenomic analysis at the end of aerobic exposure, it was observed that 60% AA served as a growth substrate for lactic acid bacteria (LAB) through the biosynthesis pathways of phenylalanine, tyrosine, and tryptophan; moreover, glycoside hydrolases (GHs) were also involved in the degradation of recalcitrant polysaccharides in grasses into easily absorbable monosaccharides and oligosaccharides, thereby improving the fermentation quality of silage. Un-expectedly, the addition of AA was found to reduce the relative abundance of antibiotic resistance genes. WCC ensiled with 60% AA exhibited excellent fermentation quality and aerobic stability, providing a theoretical basis for understanding the mechanisms of AA improves the quality of WCCS during the aerobic exposure phase.