Effect of Various Strains of Lactobacillus buchneri on the Fermentation Quality and Aerobic Stability of Corn Silage

The aerobic deterioration of silage nutrients is inevitable in tropical countries, causing negative consequences in animal production systems. Aiming to minimize the losses, the effects of Lactobacillus buchneri strains on fermentation profile and aerobic stability of corn silages were evaluated. The experiment was conducted under a completely randomized design with 13 treatments and three replicates. The treatments were noninoculated, commercial L. buchneri (CI), and 11 wild strains of L. buchneri: LB-56.1, LB-56.2, LB-56.4, LB-56.7, LB-56.8, LB-56.9, LB-56.21, LB-56.22, LB-56.25, LB-56.26, and LB-56.27. The treatments could be divided into three different groups according to silage pH and acetic acid concentration. Silages inoculated with LB-56.1, LB-56.4, and LB-56.9 presented higher pH, whereas intermediate values were observed for LB-56.2, LB-56.7, and LB-56.8. The highest acetic acid production was observed for LB-56.1 and LB-56.7. On the other hand, lowest concentrations were found for CI, LB-56.22, LB-56.25, LB-56.26, and LB-56.27. Higher amounts of NH3–N were observed for LB-56.8, LB-56.21, LB-56.22, and LB-56.27 silages than others. Silage inoculation with CI, LB-56.1, LB-56.2, LB-56.4, LB-56.8, LB-56.9, and LB-56.25 strains had higher aerobic stability than others (59.7 vs. 41.2 h). The L. buchneri strains LB-56.1, LB-56.2, LB-56.4, LB-56.8, LB-56.9, and LB-56.25 provided potential features to improve the aerobic stability of corn silage.

Effect of cactus pear as a moistening additive in the production of rehydrated corn grain silage

The current study aimed to evaluate the effects of cactus pear as a moistening additive on fermentative and microbiological characteristics, aerobic stability (AS), chemical composition and in situ rumen degradability of corn grain silage at different opening times. A completely randomized experimental design was adopted in a 4 × 3 factorial scheme with four levels of dry matter (DM) (50; 60; 70 and 80% of DM) and three opening times (30; 60 and 120 days after ensiling), with four replications. There was an effect of interaction (P < 0.05) between the DM levels and opening times on silage yeast population, effluent losses, gas losses, dry matter recovery (DMR), AS of the silage and on lactic acid bacteria, mould and yeast populations after AS trial. The 60% DM level presented DMR values above 930 g/kg of DM. However, the lowest AS time (96.52 h) was observed in silages with 60% DM at 60 days after ensiling, although all silages have shown high AS. The DM in situ degradability of the ensiled mass increased after the ensiling process at all DM levels and opening times, with the 60% DM content showing the best result. When using cactus pear as a corn grain moistening additive, the 60% DM level is recommended when the opening time is up 120 days.

Biotechnology of Newly Created Bacterial Composition for Siloing Based on Lactic Acid Bacteria

Peculiarities of high-quality silage production are the use of biological products based on lactic acid bacteria. The composition of such starters varies greatly according to the use of bacterial cultures, so among the starters available on the market, the range of their effectiveness is also different. It is very common to use a one-sided approach to the choice of bacterial components, which in combination with imperfect production technology have low preservative activity. The study of combined preparations, which combine homo- and heterofermentative types of lactic acid fermentation, allows to stabilize the preservative properties throughout the ensiling time, and increase the aerobic stability of the silage after access of oxygen. Aim. Development of biotechnology of bacterial preparation for corn ensiling, optimization of cultivation conditions of newly created bacterial composition, and selection of cryoprotectants for its lyophilization. Methods. The combined preparation was created on the basis of heterofermentative strain Lactobacillus buchneri 3806 combining it in two- and three-strain compositions with other representatives of lactic acid bacteria, which are characterized by obligate homofermentative and facultative heterofermentative types of metabolism. Optimization of the environment and technological parameters was carried out using a central-compositional plan, further statistical analysis of the obtained data and determination of optimal values of input parameters according to the created mathematical model of optical density response. The effectiveness of the selected protective media was tested for the survival of bacteria after lyophilization. Results. The most effective bacterial composition was found during experiments: L. buchneri 3806, Enterococcus faecium C-8-12, L. plantarum 3216. The effectiveness of the obtained composition was tested by laboratory silage of corn. Tests of the drug based on the selected bacterial composition showed an improvement in the chemical composition of the silage compared to the untreated control and treated only with monoculture L. buchneri 3806, namely: there was a decrease in dry matter loss by 2.21% and 2.04%, 22 due to the increase of lactic acid content, and increase of aerobic stability of silage – 341 h against 57 h of the control sample, and 313 h in case of using monoculture. For the obtained bacterial composition, the culture medium of the following composition was optimized: base (hydrolyzed milk with the addition of the following components: monosubstituted potassium phosphate – 2 g/L; 5-aqueous manganese sulfate – 0.05 g/L; 7-aqueous magnesium sulfate – 0.2 g/L; twin-80 – 1.0 g/L); glucose – 19.7 g/L; yeast extract – 7.8 g/L; corn extract – 23.6 g/L; peptone – 9.1 g/L; sodium citrate – 6.6 g/L; sodium acetate – 3,4 g/L. Cultivation of the bacterial composition on an optimized medium made it possible to obtain the maximum biomass yield, at which the optical density was 2.01 units, which is almost twice as much as the value obtained by culturing the same composition in MRS medium. The optimal technological parameters of culturing the bacterial composition were established, namely the best growth was observed at a temperature of 36.4±0.4°C with constant maintenance of the pH value in the culture medium at the level of 6.5±0.1 units. In addition, the optimal composition of the protective medium containing sodium citrate, sucrose and agar was selected, and ensures the survival rate of lactic acid bacteria 98.4% after lyophilization. Conclusions. The newly formed bacterial composition can be used for the production of preparations for corn silage, and tested on other raw materials, in particular on some perennial legumes (alfalfa, clover), and the conditions of its production can be used to scale the technology.

Succession of Microbial Communities of Corn Silage Inoculated with Heterofermentative Lactic Acid Bacteria from Ensiling to Aerobic Exposure

To further explore the effects of heterofermentative lactic acid bacteria (LAB) on silage fermentation and aerobic stability, whole-plant corn at around the 1/2 milk-line stage was freshly chopped and ensiled in laboratory silos with deionized water (control), Lactobacillus buchneri (LB), or L. rhamnosus (LR). Each treatment was prepared in triplicate for 3, 14, and 60 d of fermentation, followed by 3 and 7 days of aerobic exposure. The dynamic changes in microbial community were studied by single molecule real-time (SMRT) sequencing. The results showed that the two LAB inoculants altered the microbial communities in different ways. Succession from L. plantarum to L. buchneri and L. rhamnosus was observed in LB- and LR-treated silage, respectively. Both silages improved aerobic stability (82 and 78 h vs. 44 h) by occupying the microbial niche to produce higher levels of acetic acid at terminal fermentation. Because Acetobacter fabarum dominated in the silages after aerobic exposure, beta diversity dramatically decreased. In this study, a. fabarum was reported for the first time in silage and was related to aerobic spoilage. The two heterofermentative LAB produced acetic acid and improved the aerobic stability of the corn silage by occupying the microbial niche at terminal fermentation. Inoculated L. rhamnosus had a greater pH for a longer period of time after opening and less DM loss at day 7.

Aerobic stability of alfalfa silage and methods of its improvement

Alfalfa is a non-silage crop, the silage of which became possible after the effect of drying was detected. A special feature of alfalfa is the intensive proteolysis that occurs during silage, and the prolonged development of undesirable microflora due to the slow acidification of feed. The objective of the research was to determine the effectiveness of the use of Biotrof, Biotrof 111, Biotrof 2+ and Biotal Axfast NS Gold in the silage of dried (37.07% SV) alfalfa mass. It was found that the use of these drugs contributed to the rapid acidification of feed to a pH of 3.97-4.08, against a pH of 4.96 in silage without additives, which led to the suppression of the vital activity of undesirable bacteria, a decrease in the breakdown of nutrients to gaseous products by 1.7-2.3 times and the accumulation of ammonia by 1.5-4.0 times. Due to the high resistance of alfalfa silage to aerobic spoilage, the use of bacterial preparations did not lead to an improvement in the aerobic stability of the silage, but by restraining the development of some yeasts, including pathogenic ones, and fungi of the Aspergillus sp. species, it helped to improve the sanitary status of the feed. Yeasts of the genera C. gattii and D. hansenii serve as marker organisms, an increase in the number of which indicates the occurrence of aerobic spoilage in the feed.

Aerobic stability of tifton 85 silage with and without pre-drying in the sun

The objective of this study was to evaluate pH, ammoniacal nitrogen, and aerobic stability of silage of Tifton 85 grass silage with two dry matter contents at different silos opening times. The experimental design was completely randomized, in a subdivided plots scheme, in which the silages constituted the plots and aerobic exposure times the subplots, with four replications. To verify the aerobic stability of the silages, the temperature and pH were analyzed at seven hours after the silos were opened (1, 24, 48, 72, 96, 120, and 144 hours). The pH reached adequate levels for conservation only after 90 days of fermentation for the silages with and without pre-drying in the sun. Ammoniacal nitrogen remained below the recommended limits in both silages. As for the silage temperature, no loss of aerobic stability was observed. However, the observed pH revealed a break instability after 72 hours when the silos were opened at 28 days, with no changes for the remaining silage periods. It is possible to obtain suitable silages from Tifton 85 with or without pre-warming in the sun, however, a minimum fermentation period of 90 days should be adopted. The studied silages presented high aerobic stability, but when kept silage for only 28 days, they should be consumed by the animals within 48 hours after the supply.

Effects of different banana crop residue hays on ensiling BRS capiaçu grass on fermentation profile, aerobic stability and nutritional value of silage

The objective of this study was to evaluate the BRS capiaçu grass silage combined with different hays of banana crop residue on fermentation profile, aerobic stability and nutritional value. The treatments consisted of elephant grass cv. BRS capiaçu (Pennisetum purpureum Schum.) ensiled with 37.44% banana peel hay, 36.06% banana pseudostem hay and 37.00% banana leaf hay, on a dry matter (DM) basis and control silage (no additive). The experimental design used was completely randomized, with five treatments and five replicates. Forage was collected when it reached 3.5 meters in height (90 days). Experimental PVC silos of known weight, 50 cm long, 10 cm diameter, were used for silage making. For all treatments, silage aerobic stability breakdown started after 64 hours exposure to air. The BRS capiaçu grass control silage or silage combined with pseudostem hay (mean of 73.15 kg t GM-1) presented effluent losses 40.46% higher than those observed for BRS capiaçu grass silage + banana leaf hay and 69.17% in relation the BRS capiaçu grass silage + banana peel hay. The inclusion of banana crop residue (hay) when ensiling BRS capiaçu grass decreased 13.93% gas losses compared to the control silage (mean of 3.11% DM). Higher values of total digestible nutrients, metabolizable energy and digestible energy content was found in BRS capiaçu grass silage + with banana peel hay. The greater in vitro dry matter digestibility and in vitro neutral detergent fiber digestibility was observed for BRS capiaçu grass silage combined with pseudostem hay. The inclusion of 37.44% banana peel hay improves the fermentation profile and aerobic stability of BRS capiaçu grass silage.