Effects on microbial diversity of fermentation temperature (10°C and 20°C), long-term storage at 5°C, and subsequent warming of corn silage

Abstract

Objective To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from 5°C to 25°C on corn silage which was previously fermented at ambient or low temperature. Methods Whole-plant corn silage was fermented in vacuum bag mini-silos at either 10°C or 20°C for two months and stored at 5°C for two months. The mini-silos were then subjected to additional incubation from 5°C to 25°C in 5°C increments. Bacterial and fungal diversity was assessed by polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature. Results A temperature of 10°C during fermentation restricted silage fermentation compared to fermentation temperature of 20°C. As storage temperature increased from 5°C to 25°C, little changes occurred in silages fermented at 20°C, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to 5 log 10 colony forming unit/g fresh materials) were detected at 15°C and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at 10°C, no significant changes were observed in most silage characteristics when temperature was increased from 5°C to 20°C. However, above 20°C, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from 20°C to 25°C. Conclusion Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at 20°C indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

Effect of Ensiling Density and Storage Temperature on Fermentation Quality, Bacterial Community, and Nitrate Concentration of Sorghum-Sudangrass Silage

“…The normal storage temperature (25 • C) might be a good temperature for higher LAB activity during the earlier fermentation process in silage, as reflected by the higher LA and lower pH in NT treatments (Table 2). Previous studies also revealed similar results regarding the effect of storage temperature on the fermentation characteristics of whole-plant corn silage (Zhou et al, 2016(Zhou et al, , 2019Ferrero et al, 2021). However, the LAB in the final silage might be inhibited by the low pH condition (McDonald et al, 1991), which resulted in lower LAB count in NT treatments (Table 3).…”

Microbiota succession during aerobic stability of maize silage inoculated with Lentilactobacillus buchneri NCIMB 40788 and Lentilactobacillus hilgardii CNCM‐I‐4785

“…However, the length of the fermentation period and incubation temperature differed in the two studies, and in the former study, the bag silos were stored outside. Considering the lower average temperatures encountered during the incubation of the bag silos, we would expect microbial succession to be slower than in mini‐silos stored at room temperature (Zhou et al, 2019). The presence of Leuconostocaceae at this late stage of ensiling is rare in corn silage, considering that upon the opening of the bag silos, pH was below 4.0, a pH to which species belonging to this family are sensitive.…”

Application of linear and nonlinear models for the temperature and pH behavior of a solid state fermented cocoa shell (<em>Theobroma cacao</em> L.)

“…The cubic model (Y = a + bx + cx 2 + dx 3 ) was the one that presented the best fit for the evaluation of the temperature behavior (Table 2, Figure 1) and pH (Table 3, Figure 2) of the cocoa shell SSF. However, Zhou et al (2019) mention that temperatures between 20 and 25 °C, guarantees the growth of lactic acid bacteria colonies such as Lactobacillus buchneri, these favors a rapid increase in the concentration of lactic acid, and the rapid decrease in pH to favor the silage process (Muck 2013;Wang et al 2017;Caicedo et al 2019b), in this study the cocoa shell SSF remained within the optimum temperature ranges for the production of good quality silage. On the other hand, temperatures below 10 °C or above 37 °C affect the fermentation process, leading to poor quality silage and low aerobic stability (Zhou et al 2019;Bernardes et al 2018).…”

“…However, Zhou et al (2019) mention that temperatures between 20 and 25 °C, guarantees the growth of lactic acid bacteria colonies such as Lactobacillus buchneri, these favors a rapid increase in the concentration of lactic acid, and the rapid decrease in pH to favor the silage process (Muck 2013;Wang et al 2017;Caicedo et al 2019b), in this study the cocoa shell SSF remained within the optimum temperature ranges for the production of good quality silage. On the other hand, temperatures below 10 °C or above 37 °C affect the fermentation process, leading to poor quality silage and low aerobic stability (Zhou et al 2019;Bernardes et al 2018). On the other hand, immediately after the fermentation of the raw material, a variation in pH occurs, which reaches values between 5.5 and 6 due to the low concentration of lactic, acetic and propionic acid in the medium (Kung et al 2018).…”