Characterization of mycotoxins and microbial community in whole-plant corn ensiled in different silo types during aerobic exposure

Abstract

Silage can be contaminated with mycotoxins and accidental fungi after aerobic exposure. The study assessed the effects of bunker silos (BS), round bales (RB), and silage bags (SB) on the nutritional characteristics, fermentation quality, aerobic stability, mycotoxin levels and microbial communities of whole-plant corn silage (WPCS). After 90 days of fermentation, silages were opened and sampled at 0, 1, 3, 5, 7, and 9 days of exposure. SB group conserved higher lactic acid and dry matter contents and a lower pH value than other groups after 9 days of exposure (p < 0.05). The SB group showed the longest aerobic stability (202 h) among all silages (p < 0.05). The concentrations of aflatoxin B1, trichothecenes and fumonisin B1 were significantly lower in SB after 9 days of exposure (p < 0.05). Acetobacter became the dominant bacteria in BS and RB groups after 5 days of exposure. However, Lactobacillus still dominated the bacterial community in SB group. Acetobacter was positively correlated with pH, acetic acid content, and ammonia-N content (p < 0.05). Lactobacillus was positively correlated with Kazachstania and Candida abundances (p < 0.01) but negatively correlated with Fusarium abundance (p < 0.05). Considering the feed value and food safety of silage in the feeding process, silage bags are recommended for WPCS according to the observed nutritional quality, fermentation index and mycotoxin content.

Effect of Regulation of Whole-Plant Corn Silage Inoculated with Lactobacillus buchneri or Bacillus licheniformis Regarding the Dynamics of Bacterial and Fungal Communities on Aerobic Stability

“…The 20 g silage samples were combined with 180 mL of sterile water and refrigerated for 18 h at 4 °C. Using a pH meter with a glass electrode (PB-10, Sartorius Group, Göttingen, Germany), the pH of the extract was determined [ 11 ]. Using a 210 nm UV detector (Waters2414, Waters Corporation, Milford, MA, USA) and a chromatographic column (Sepax Technologies, Inc., Newark, DE, USA), high-performance liquid chromatography (Waters1525, Waters Corporation, Milford, MA, USA) was used to determine the organic acid content.…”

“…Whole-plant corn silage plays a major role as a feed for dairy cattle around the world as a valuable source of energy and nutrients [ 9 , 10 ]. However, with its high residual soluble carbohydrate content and the lactic acid it produces during fermentation, it provides ideal conditions for yeasts and filamentous fungi to multiply, causing aerobic deterioration when whole-plant corn silage is exposed to oxygen [ 11 ]. Compared to lactic acid, acetic acid is more resistant to fungal fermentation [ 4 ].…”