Effect of different organic acid additives on the fermentation quality and bacterial community of paper mulberry (Broussonetia papyrifera) silage

Abstract

To investigate the effects of different organic acid additives and their concentrations on the fermentation quality and bacterial community of paper mulberry silage, paper mulberry was left untreated (control) or was treated with ethylenediaminetetraacetic acid (EDTA), propionic acid (PA) or citric acid (CA), the amount of each additive was 2 g.kg−1 FM, 5 g.kg−1 FM and g.kg−1 FM. All groups were ensiled for 3, 7, 15, 30 and 60 days. Compared to the control, adding EDTA reduced protein breakdown, preserved more water-soluble carbohydrates of the silages (WSCs, 24.74 g.kg−1 DM), and high concentrations of EDTA inhibited the activity of undesirable microorganisms. Adding PA increased the abundance of Lactiplantibacillus and decreased the abundance of Enterococcus, and it caused a rapid decrease in the pH of the silage at an early stage (from 6.50 to 5.31) while altering the microbiota, and low concentrations of PA resulted in high LA (66.22 g.kg−1 DM) concentration and low PA (9.92 g.kg−1 DM) concentration at 60 days of ensiling. Different concentrations of additives altered the microbial community of paper mulberry to different degrees. High concentrations of PA and CA can increase the abundance of Lactiplantibacillus. High concentrations of CA resulted in a rapid decrease in silage pH at an early stage and higher WSC concentration. These results suggest that EDTA, PA and CA can be used as additives to improve the quality of paper mulberry silage.

Synergistic effects of ferulic acid esterase‐producing lactic acid bacteria, cellulase and xylanase on the fermentation characteristics, fibre and nitrogen components and microbial community structure of Broussonetia papyrifera during ensiling

“…Nutritional characteristics of the raw B. papyrifera materials The nutritional characteristics of B. papyrifera before ensiling are shown in Table 1. The DM and CP contents of the whole B. papyrifera plant were regulated at 350.74 and 140.86 g kg −1 DM, respectively, which was similar to the results reported by Li et al 5 In addition, fresh paper mulberry contained 101.38 g kg −1 total nitrogen (TN), which was similar to the results previously obtained for mulberry. 11 The contents of NDIP and ADIP were 93.79 and 8.08 g kg −1 DM, respectively, which indicated a high level of undegradable rumen protein 20 in paper mulberry.…”

“…21,22 The fibre degradation of the high lignocellulosic fraction needs to be improved to promote fermentation and digestibility in animals. The number of epiphytic LAB was greater than that reported by Li et al 5 Enterobacteriaceae were not detected in any of the groups.…”

“…The number of undesirable bacteria in the LP addition treatment groups was lower than that in the CK, CE and XY groups throughout the fermentation process. Moreover, yeast was detected in the LP addition treatment groups only on the third day, which was similar to the results of a previous study 5…”

“…These findings were probably obtained due to the high buffer energy value of B. papyrifera. 5 LP addition directly led to a rapid decrease in the pH of the silages, which may be attributed to the lactic acid production rate of L. plantarum RO395 combined with the function of FAE production. The addition of LAB can promote the efficient utilization of sugars and the production of large amounts of acidic substances.…”

“…2 Ensiling can reduce and soften fibres in the presence of cellulolytic additives, increase the feeding value and resolve issues related to the preservation of feed. 3,4 However, the low content of water-soluble carbohydrate (WSC) and high buffer energy lead to difficulty in preparing high-quality silage of B. papyrifera, 1,5 in addition to its high contents of lignocellulose and fibre polymers. 6 Previous studies have indicated that lignocellulose consists mainly of cellulose, hemicellulose, lignin and some other components.…”