Fermentation quality, aerobic stability, and microbiome structure and function of Caragana korshinskii silage inoculated with/without Lactobacillus rhamnosus or Lactobacillus buchneri

Abstract

Caragana korshinskii is a forage shrub species with high-protein content that has been extensively used to alleviate feed shortages for ruminants in northern China. Herein, we investigated the effects of Lactobacillus rhamnosus and Lactobacillus buchneri on the fermentation quality, aerobic stability, and microbiome composition and the predicted functional characteristics of C. korshinskii silage. C. korshinskii silages were inoculated with and without L. rhamnosus or L. buchneri. After 14 and 56 days of ensiling, the aerobic stability was determined. The results revealed that after 14 and 56 days of ensiling, L. rhamnosus- and L. buchneri-inoculated silage exhibited increased acetic acid and lactic acid contents, whereas the pH and 2,3-butanediol and butyric acid contents were decreased compared with those of the control silage. The control silages that were opened at 14 and 56 d, deteriorated during the aerobic stability test, whereas silages inoculated with L. rhamnosus and L. buchneri did not exhibit any aerobic deterioration. The control silage showed an increased Clostridium and Bacillus abundance, whereas Lactobacillus abundance decreased compared with L. rhamnosus- and L. buchneri-inoculated silages, following the 7 days of aerobic exposure. The fermentation parameters were associated with microbial communities, including Lactobacillus, Pedicoccus, Weissella, Clostridium, and Bacillus. Carbohydrate and amino acid metabolisms in the control silage decreased after 7 days of aerobic exposure compared with lactic acid bacteria-inoculated silages. To conclude, next-generation sequencing combined with 16S ribosomal RNA gene-predicted functional analyses might provide new information about the silage quality during fermentation and the aerobic stability.

Effects of lactic acid bacteria inoculants on the nutrient composition, fermentation quality, and microbial diversity of whole-plant soybean-corn mixed silage

“…After 56 days of ensiling, silage treated with LB exhibited a higher acetic acid content than the three other groups, significantly higher aerobic stability than the CK and LP groups, and the lowest yeast and mold counts post-exposure. These findings align with those of Keshri et al (2019) and Wu et al (2023) , confirming that silage supplemented with LB demonstrates superior aerobic stability.…”

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 coverage values of all treatment groups in regards to bacteria and fungi were greater than 0.99, indicating that sequencing has adequately captured most bacterial and fungal communities. With prolonged exposure to oxygen, the Shannon and Chao indices of the bacterial and fungal communities in each treatment decreased, while the Simpson index increased (p < 0.05), indicating a decline in both the diversity and abundance of the bacterial and fungal communities [21]; this result is consistent with what has been found in previous research [20], which implies that aerobic microorganisms that are tolerant to low amounts of acid proliferate in whole-plant corn silage [30] and become relatively simple during aerobic exposure. In comparison with CK7, in the fungal community, the Chao and Shannon indexes of the BL7 group were higher, while the Simpson index was lower (p < 0.05), which suggests that inoculation with BL maintains the diversity of fungal communities during aerobic exposure.…”

“…An essential metric for assessing the fermentation impact of silage is the pH value [ 25 ]; LB0 and BL0 had pH values that were lower than those of CK0 ( p < 0.05), and in many studies, inoculation with LB increases the pH value [ 26 , 27 ]. However, the results of some studies demonstrate that inoculation with LB resulted in a decrease in pH value [ 28 , 29 , 30 ]. In contrast to CK7, the pH value of the BL7 group was lower ( p < 0.05), probably due to the fact that, at this time, the lactic acid bacteria number of BL7 was higher than that of the CK group ( p < 0.05), and the number of filamentous fungi was lower than in the CK group ( p < 0.05).…”