Fermentation Characteristics, Chemical Composition, and Aerobic Stability in Whole Crop Corn Silage Treated with Lactic Acid Bacteria or Artemisia argyi

Abstract

Whole crop corn silage (WCCS) been an important source of roughage for confined ruminants. However, at the silage feed-out phase, the rise in temperature and relative humidity under aerobic conditions breeds the production of undesirable microorganisms, such as yeast and mold. In order to investigate the conservation characteristics and aerobic stability underlying the effects of additives in whole crop corn silage (WCCS), whole crop corn (WCC) at the milk-ripe stage was ensiled with Lentilactobacillus (L.) buchneri (LB) and different proportions of Artemisia argyi (AA) for 90 days (d) at room temperature, respectively, and aerobic exposure after 90 d fermentation was also conducted. 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, with the lactic acid concentration at the end of aerobic exposure significantly higher than in all other treatment groups, at 98.21 g/kg DM (p < 0.01), which decreased the relative abundance of none wanted microorganisms and reduced the content of fungal toxins (p < 0.05). After 90 d of fermentation, LB also increased the organic acids and reduced the pH compared with control, thereby improving fermentation quality. 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, 60% AA could improve the fermentation quality and aerobic stability of silage through the biosynthetic pathways of phenylalanine, tyrosine and tryptophan, as well as by participation in the hydrolysis of glycoside hydrolases (GHs). Unexpectedly, 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 which improve the quality of WCCS during the aeration phase.