Improving the nutritive value, in vitro digestibility and aerobic stability of Hedychium gardnerianum silage through application of additives at ensiling time

The effects of applying cellulase and laccase on fermentation quality and microbial community in mixed silage containing corn stover and wet brewer's grains

Objective

The purpose of this experiment was to explore the effect of adding cellulase and laccase on fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains. Try to a new approach for the proper preservation and utilization of the agro-industrial by-products (corn stover and wet brewer's grains).

Methods

The experiment was divided into four groups: CK (control), C (cellulase, 120 U/g fresh matter [FM]), L (laccase, 50 U/g FM), CL (cellulase 120 U/g FW and laccase 50 U/g FM), and the chemical composition, fermentation quality, microbial population and microbial community in mixed silage of corn stover and wet brewer's grains after 30 day's fermentation were determined.

Results

Compared to control, the addition of cellulase significantly increased crude protein (CP), water-soluble carbohydrate (WSC), lactic acid bacteria (LAB) counts, while significantly decreased the neutral detergent fiber (NDF), acid detergent fiber (ADF) content (P < 0.05). Adding laccase significantly decreased the acid detergent lignin (ADL) content (P < 0.05). Combined application of cellulase and laccase significantly increased the CP, WSC content and LAB counts, while significantly decreased pH value, NDF, ADF and ADL content (P < 0.05), thereby improving fermentation quality. In addition, the application of cellulase and laccase increased the abundance of Firmicutes and LAB genera, and decreased microbial diversity level of the sample.

Conclusion

The combined application of cellulase and laccase further improved fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains.

Toward making a high-quality silage from common reed (Phragmites australis)

The effects of the addition of molasses (5 and 10% of dry matter: DM basis; M5 and M10 respectively) with or without urea (2%; U2, U2 + M5 and U2 + M10) on chemical and mineral composition, silage quality, microbial populations, buffering capacity and fermentation/digestion characteristics of common reed (Phragmites australis) ensiled under anaerobic conditions were investigated. The additives changed the silage quality of common reed compared with the control. Crude protein content was significantly (p < 0.0001) increased in urea-containing silages, whereas ash-free neutral detergent fibre concentration decreased in M10 compared with the control (p = 0.05). Treatment with 2% urea (U2) resulted in the reduction of most measured minerals with a severe decrease in iron concentration. The amount of gas produced after 96 h of incubation was, respectively, higher for U2, M10, U2M10, U2M5 and M5 compared with the control (p < 0.0001). Although the greatest in vitro dry matter digestibility and in vitro organic matter digestibility (96 h) were observed in U2 (p < 0.0001), no significant differences were found between U2 and M10. Supplementation with 10% molasses (M10) significantly increased lactic acid concentration, aerobic stability and total bacteria compared with other treatments (p < 0.0001). Moreover, DM loss (p = 0.0004), total yeast and mould (p < 0.0001) were significantly decreased as a result of 10% molasses treatment. Overall, it can be suggested that treating silage with 10% molasses (M10) has the potential to efficiently improve the nutritive value of common reed.

Purdue improved crop storage bag for kocho fermentation; Ethiopian traditional fermented food from Enset (Ensete ventricosum)

Enset (Ensete ventricosm) is a multipurpose crop serving millions of Ethiopians as an alternative food source. However, the traditional kocho preparation is labor-intensive and results in poor quality. This study evaluated Purdue improved crop storage (PICS) bag as an alternative to an underground pit for kocho fermentation. The experiment was arranged in a factorial design with two fermentation systems (underground pit and PICS bag) and three fermentation times (30, 45 & 60 days) with 5 replications. Physico-chemical, proximate composition, microbial, and sensory evaluations of kocho were conducted following standard procedures. The results have revealed that protein and moisture contents were increased with fermentation time while crude fiber, carbohydrate, and total energy were decreased regardless of fermentation systems. The microbial results have demonstrated a reduction with extended fermentation but no significant difference between PICS and the underground pit. The sensory results have shown that PICS bag-fermented kocho has better overall sensory acceptability regardless of fermentation time. Generally, PICS bag-fermented kocho for 60 days has shown overall better kocho quality. The finding revealed that PICS bags could be used as an alternative to the traditional underground pit for better kocho quality. Further validation of the PICS bag as a fermentation container with various enset varieties and seasons with extended fermentation time is needed.

Can Alhaji maurorum as a halophyte plant be ensiled with molasses and Saccharomyces cerevisiae well?

Alhagi maurorum (Caspian Manna, AM) is a species of legume found commonly in the semi-arid region of the world. Nutritional aspects of silage prepared from AM have not been scientifically investigated so far, therefore, in this study, chemical-mineral composition, gas production parameters, ruminal fermentation parameters, buffering capacity, and silage characteristics of AM were investigated by standard laboratory methods. Fresh AM was ensiled in the mini-silos (3.5 kg) and treated with (1) no additive (control), (2) 5% molasses, (3) 10% molasses, (4) 1 × 10⁴ CFU of Saccharomyces cerevisiae [SC]/g of fresh silage, (5) 1 × 10⁴ CFU of SC/g of fresh silage + 5% molasses, (6) 1 × 10⁴ CFU of SC/g of fresh silage + 10% molasses, (7) 1 × 10⁸ CFU of SC/g of fresh silage, (8) 1 × 10⁸ CFU of SC/g of fresh silage + 5% molasses, and (9) 1 × 10⁸ CFU of SC/g of fresh silage + 10% molasses for 60 days. The lowest concentrations of NDF and ADF were related to treatments no. 6 and 5, respectively (p < 0.0001). The ash content as well as sodium, calcium, potassium, phosphorus and magnesium were highest in treatment no 2. Silages containing 10% molasses (no. 3) had the highest and lowest lactic (p < 0.0001) and butyric (p < 0.0001) acids, respectively. The highest amount of potential gas production was observed in treatments no. 5 and 6, respectively (p < 0.0001). Total yeast was decreased with increasing molasses in the silages (p < 0.0001). Acid-base buffering capacity was also highest in treatments no. 6 and 5, respectively (p = 0.0003). In general, due to the fibrous nature of AM, it is recommended to add molasses at levels of 5 or 10% when ensiling. The silages containing SC at a lower level (1 × 10⁴ CFU) along with higher levels of molasses (10% of DM) had better ruminal digestion-fermentation characteristics compared to other silages. Also, the addition of molasses improved the internal fermentation characteristics of AM in the silo.

Effects of Adding Ethanol Extract of Propolis on the Fermentation Quality, Aerobic Stability, Fatty Acid Profile, and In Vitro Digestibility of Alfalfa Silages

This study was planned to determine the effects of ethanol extract of propolis on the fermentation quality, fatty acid profile, aerobic stability, and in vitro digestibility of alfalfa silages. The ethanol extract of propolis was added to alfalfa at levels of 1000 mg/kg (PROP1), 2000 mg/kg (PROP2), and 3000 mg/kg (PROP3); propolis was not added to the control (CON) group. After the propolis was added, the pH value of the alfalfa silage declined, and the crude protein content was effectively preserved (p < 0.05). Adding propolis to alfalfa silages caused crude fiber, neutral detergent fiber, and acid detergent fiber (p < 0.05) to decrease. The ethanol extract of propolis significantly improved the lactic acid content and reduced the NH3-N content (p < 0.05). Propolis significantly improved the unsaturated fatty acid content (p < 0.05) and reduced the saturated fatty acid content (p < 0.05). In addition, propolis significantly improved the relative feed value, the digestibility of the organic matter, and the in vitro metabolic energy content (p < 0.05). These results show that the ethanol extract of propolis improves the silage quality of last cutting alfalfa silages, and has potential as an antimicrobial silage additive.

Fermentation Quality, Bacterial Community, and Aerobic Stability of Perennial Recut Broussonetia papyrifera Silage with Different Additives and Wilting Time

Broussonetia papyrifera L. (paper mulberry) is an alternative woody plant, which can used to replace part of the protein feed for ruminants. Ensiling is an effective way to preserve fresh pasture and to solve the problem of stable storage and feed conversion of paper mulberry in the rapid growth period. However, low dry matter (DM), water-soluble carbohydrate, and lactic acid bacteria (LAB) reduce the quality of paper mulberry silage. This study assesses the influence of wilting time (0 h and 3.5 h; lighting: 3.43 × 104 Lux) and three additives (Enterococcus durans, CL; cellulase, CE; and formic acid, FA) on the fermentation quality, aerobic stability, and bacterial community of whole plant B. papyrifera silage. The whole plant B. papyrifera sample was mowed and wilted for 0 h and 3.5 h, and then had CL, CE, or FA added, followed by 60 days of ensiling. The results show all silage samples had high fermentation quality with pH below 4.2, ammonia-nitrogen below 100 g/kg DM, and no detectable butyric acid. The additives protected the DM and the crude protein from protease activity (p < 0.05), and CL was the most effective among them. Furthermore, wilting time influenced the silage’s bacterial communities, but overall, CL treatment had the greatest impact on bacterial communities. Wilting time and formic acid treatment significantly improved aerobic stability (p < 0.05). Enterococcus was positively correlated with lactic acid (LA), while negatively correlated with LA and Weissella (p < 0.001). Enterococcus was identified as the main driver of the whole plant paper mulberry ensiling process in the present study. In conclusion, compared to other additives, LAB is the most effective and economical to improve the fermentation quality and reduce the protein degradation of whole plant paper mulberry silage. Our findings provide a theoretical basis to improve the quality and production of paper mulberry silage.

Effects of Lactic Acid Bacteria and Molasses Additives on Dynamic Fermentation Quality and Microbial Community of Native Grass Silage

Ensiling native grass is an effective method to protect the nutritional quality of forage and alleviate feed shortages in the cold winter of the Inner Mongolian Plateau. To improve the usability of native grass resources as feed in China, the effects of lactic acid bacteria and molasses additions on the microbial population, fermentation quality, and nutritional quality of native grass during silage were investigated. Treatments were a control treatment with no additive (CK), lactic acid bacteria (L), molasses (M), and lactic acid bacteria in combination with molasses (L+M), all of which were stored at ambient temperature (17-28°C) for 7, 14, 30, and 60 days. The results showed that all additives improved nutritional value and fermentation quality with low pH and ammonia nitrogen (NH3-N) and high crude protein (CP) and water soluble carbohydrate (WSC) than control silage over the ensiling period. Compared with L or M silage, the L+M silage combination improved fermentability, as evidenced by higher LA content and a faster pH drop during the first 7 days of ensiling. With prolonged ensiling time, the combined addition of L and M could increase the count of desirable Lactobacillus, decrease microbial diversity, and inhibit the growth of undesirable microorganism, such as Clostridia, Escherichia, and Enterobacter abundance compared with silage treated with CK, L. or M. Application of L together with M could further improve the silage quality of native grass by altering bacterial community structure. In summary, the addition of lactic acid bacteria and molasses increased the relative abundance of Lactobacillus of native grass silage and improved fermentation quality.

Characterization of Green Manure Sunn Hemp Crop Silage Prepared with Additives: Aerobic Instability, Nitrogen Value, and In Vitro Rumen Methane Production

Sunn hemp (SH, Crotalaria juncea, L.) is a tropical multiple-purpose legume. The green manure SH (GMSH) crop might display protein ecology in sustaining ruminants; however, its silage features remain unclear. To efficiently prepare GMSH crop silage, additive treatments consisting of control (no additive, CON), molasses (MO), Acremonium cellulase (AC), and Lactobacillus casei TH14 strain inoculant (TH14) were implemented using a completely randomized design. Repeated measurements were done after silage (AE conditions) in a small-scale silo system for 120 days and after aerobic instability (AE + AIS conditions). Briefly, ensiling loss and aerobic stability ranged from 150 to 175 g/kg and 8.3 to 104 days, respectively. In AE conditions, the pH ranged from 4.33 to 5.74, and MO or AC was desirable (p < 0.01) for lactic acid fermentation. AC reduced the fiber contents. MO increased soluble non-protein nitrogen by decreasing insoluble nitrogen. TH14 increased the ammonia nitrogen level and in vitro methane production. In AE + AIS conditions, AC led to more air damage to the chemical compositions and reduced digestibility in vitro. The results show that an optimization of additives could effectively modify GMSH crop silage to make it a good protein roughage source; however, more studies are required for effectively feeding ruminants.

Effect of Different Regions and Ensiling Periods on Fermentation Quality and the Bacterial Community of Whole-Plant Maize Silage

This study aimed to explore the changes in the microbial community on the silage material surface and during the ensiling process of whole-plant maize in different regions. Whole-plant maize silages were sampled in Ziyun, Guanling, and Weinning counties within warm and humid climate areas in southern China. Silages were sampled at 0, 2, 5, 10, 20, and 45 days during ensiling. The nutritional components, fermentation properties, and microbiomes were examined to evaluate the influence of sampling area and fermentation time on the quality of silage. The results showed that the pH values of all silages significantly decreased (<4.2 at ensiling day 2) during fermentation and all silages achieved satisfactory fermentation at 45 days. Butyric acid was not detected during ensiling, and the contents of acetic acid and ammonia nitrogen in the final silages were below 6 g/kg DM and 50 g/kg total nitrogen, respectively. Weissella was the dominant epiphytic bacteria of raw material in Ziyun and Weinning, while Lactobacillus was prevalent in Guanling. Lactobacillus dominated the ensiling process, and its abundance significantly increased with increasing fermentation time in the three groups. Lactobacillus was negatively correlated with pH of all silages (p < 0.05) and positively correlated with lactic acid, propionic acid and acetic acid (p < 0.05). Furthermore, the bacterial community was significantly correlated with environmental factors. Altitude had a highly positive correlation with the abundance of Stenotrophomonas, Chryseobacterium, and Massilia (p < 0.01), while precipitation was negatively correlated with these bacteria. The humidity and average temperature significantly influenced the Lactobacillus and Weissella abundances of fresh whole-plant maize. During the ensiling process, the silages from three regions had similar bacterial dynamic changes, and the Lactobacillus formed and maintained good fermentation characteristics in whole-plant maize silage.

Effect of citric acid residue and short-chain fatty acids on fermentation quality and aerobic stability of lucerne ensiled with lactic acid bacteria inoculants

The experiment aimed to compare the effects of citric acid residue (CAR) to that of three commonly used short-chain fatty acids on the fermentation quality, aerobic stability and structural carbohydrate degradation of lucerne ensiled with lactic acid bacteria (LAB) inoculants. Fresh lucerne was ensiled with distilled water (control), LAB inoculant (L), CAR + LAB inoculant (CL), formic acid + LAB inoculant (FL), acetic acid + LAB inoculant (AL) and propanoic acid + LAB inoculant (PL) for 50 days. Chemical composition and microbial populations were determined after ensiling. The residual silages ensiled for 50 days were evaluated for aerobic stability. Compared with control, CL, FL, AL and PL treatments significantly (p < 0.05) decreased pH, ammonia nitrogen (NH₃ -N) and butyric acid contents and increased lactic acid, acetic acid and propionic acid contents. Among them, CL silages had the lowest pH, dry matter and water-soluble carbohydrate (WSC) content, whereas the population of LAB and the lactic acid contents were highest. Besides, CL outperformed in enhancing fibre degradation, CL silages significantly decreased (p < 0.05) neutral detergent fibre, acid detergent fibre, hemicellulose and cellulose contents compared with control and had the highest Flieg's point. All treated-silages improved the aerobic stability compared with control, of which L improved 32 h, whereas CL, FL, AL and PL improved 46, 20, 46, >64 h, respectively. Applying a combination of CAR and LAB inoculant improved the fermentation quality and structural carbohydrate degradation of lucerne silage and had a similar effect on aerobic stability compared with other three short-chain fatty acids. The CAR had a comparable effect on enhancing the fermentation quality compared with three short-chain fatty acids. Thus, the combination of CAR and LAB inoculant might be used as an ideal additive for lucerne silage making with low WSC and high moisture content.

Microbial profile during fermentation and aerobic stability of ensiled mixtures of maize stover and banana pseudostem in South Ethiopia

AIMS

This study evaluated pH reduction and microbial growth during fermentation of maize stover (MS) mixed with banana pseudostem (BPS) under South Ethiopian conditions.

MATERIALS AND RESULTS

The MS and BPS were chopped and mixed into six treatments (T): 80% BPS plus 20% DMS (T1), 70% BPS plus 30% DMS (T2), 40% BPS plus 60% FMS (fresh MS) (T3), 20% BPS plus 80% FMS (T4), 100% FMS (T5), and 95% BPS plus 5% molasses (T6). At 0, 7, 14, 30, 60, and 90 days, pH and dry matter were determined. Microbiological quality was assessed using plate counts and Illumina MiSeq sequencing. On day 60 and 90, aerobic stability was investigated. The results showed a significant reduction in pH in all mixtures, except in T1 and T2. Lactic acid bacteria counts reached a maximum in all treatments within 14 days. Sequencing showed marked changes in dominant bacteria, such as Buttiauxella and Acinetobacter to Lactobacillus and Bifidobacterium.

CONCLUSIONS

The fresh MS and BPS mixtures and fresh maize showed significant pH reduction and dominance of desirable microbial groups.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study enables year-round livestock feed supplementation to boost milk and meat production in South Ethiopia.

Effects of Replacing Ensiled-Alfalfa with Fresh-Alfalfa on Dynamic Fermentation Characteristics, Chemical Compositions, and Protein Fractions in Fermented Total Mixed Ration with Different Additives

Simple Summary

Alfalfa (Medicago sativa) is commonly used as a high-quality protein source in fermented total mixed ration (FTMR) for ruminants. This study evaluated the fermentation characteristics, chemical compositions, and protein fractions of FTMR using fresh-alfalfa as the main ingredients replacing ensiled-alfalfa. The results showed that fresh-alfalfa FTMR exhibited a similar pH, propionic acid content and neutral detergent fiber, nonprotein, and variable to slow protein and indigestible protein levels in comparison to ensiled-alfalfa FTMR. Therefore, the use of fresh-alfalfa as a main ingredient in FTMR is promising.

Abstract

Alfalfa (Medicago sativa) is one of the high protein ingredients of fermented total mixed ration (FTMR). Additionally, FTMR is widely used to satisfy the nutrition requirements of animals. This study was conducted to confirm the fermentation characteristics, chemical compositions and protein fractions changes when replacing ensiled-alfalfa with fresh-alfalfa in FTMR with additives. Three additives were separately applied to fresh-alfalfa total mixed ration (TMR) and ensiled-alfalfa TMR, including molasses (MOL), Lactobacillus plantarum (LP) and MOL plus LP (MOL+LP). The same volume of distilled water was sprayed onto the prepared TMR as performed for the control (CK). Each treatment included 18 repetitions and opened 3 repetitions at each fermenting day (1, 3, 7, 15, 30 and 60 d). The results showed that fresh-alfalfa FTMR (F-FTMR) exhibited slight changes in the fermentation characteristics during the first 7 d and showed similar trends in terms of the pH and organic acids content to ensiled-alfalfa FTMR (E-FTMR). The lactic acid contents of F-FTMR were significantly lower than those of E-FTMR at 60 d fermentation and the ammonia nitrogen contents were lower than E-FTMR during the entire fermenting period. The crude protein of the F-FTMR was enhanced after 60 d of fermenting. F-FTMR supplemented with MOL+LP exhibited a lower nonprotein nitrogen content, variable to slow protein and indigestible protein contents, and higher fast degradable protein and true protein degraded intermediately contents at 60 d fermenting, indicating that it effectively inhibited protein degradation.

Silage making of maize stover and banana pseudostem under South Ethiopian conditions: evolution of pH, dry matter and microbiological profile

The study was conducted to evaluate the microbial dynamics during silage of maize stover and banana pseudostem in the environmental conditions of southern Ethiopia. To meet this objective, microsilos containing either maize stover or banana pseudostem, both with and without molasses, were prepared. Subsequently, samples were analysed on day 0, 7, 14, 30, 60 and 90 of the fermentation process. As a result, on day 7, all treatments except banana pseudostem without molasses showed a significant reduction in pH. It was also this silage type that supported the growth of Enterobacteriaceae longer than three other silage types, i.e. until 30 days. The yeasts and moulds and the Clostridum endospore counts also showed a reducing trend in early fermentation and afterwards remained constant until day 90. Illumina MiSeq sequencing revealed that Leuconostoc, Buttiauxella species and Enterobacteriaceae were the most abundant bacteria in the initial phases of the fermentation. Later on, Buttiauxella, Lactobacillus, Weissella and Bifidobacterium species were found to be dominant. In conclusion, silage of the two crop by-products is possible under South Ethiopian conditions. For banana pseudostem, the addition of molasses is crucial for a fast fermentation, in contrast to maize. Upscaling needs to be investigated for the two by-products.

Microbial Community Dynamics and Natural Fermentation Profiles of Ensiled Alpine Grass Elymus nutans Prepared From Different Regions of the Qinghai-Tibetan Plateau

Feed deficiency during the long cold period of a year is one of the major problems that the traditional year-round animal grazing system has faced on the Qinghai-Tibetan plateau (QTP) since ancient time. Therefore, ensiling the grasses from grassland could be a desirable feeding regime to preserve high quality forage and to alleviate the seasonal unbalanced feed supply problem on this plateau. The present study was designed to investigate dynamics of bacterial community and natural fermentation quality of ensiled Elymus nutans collected from grasslands in four different areas with different elevations [Tianzhu County (TZ), 2965 m; Golog Prefecture (GL), 3763 m; Damxung County (DX), 4228 m, and Nagqu Prefecture (NQ), 4752 m] on the QTP. The bacterial community was characterized by using the PacBio single molecule with real-time sequencing technology (SMRT). The harvested fresh E. nutans grasses were ensiled in vacuum-sealed polyethylene bags for 14, 30, 60, and 90 days. Obvious differences in the epiphytic bacterial community of the fresh E. nutans samples from the four areas were observed, which resulted in various bacterial community dynamics and fermentation qualities of ensiled E. nutans. Higher fermentation quality was observed in silage samples from Nagqu than in those from the other areas (P < 0.05). Lactic acid bacteria (LAB) involved in fermentation of E. nutans from low altitude areas consisted of Pediococcus pentosaceus, Lactobacillus sp., Leuconostoc mesenteroides, and Lactobacillus coryniformis, whereas major LAB species involved in the fermentation of E. nutans silage from high altitudes included L. mesenteroides, Lactobacillus brevis, and Lactobacillus sp. Correlation analysis between bacterial composition and fermentation quality of E. nutans silages made from the four different areas in the QTP indicated that the LAB species responsible for silage fermentation in different areas were totally different, which was mainly due to the different epiphytic bacterial compositions in fresh E. nutans before ensiling. The present results provide important information on revealing the bacterial communities and fermentation quality of ensiled E. nutans, and on future screening of LAB isolates for making high quality silage in order to alleviate feed shortage of the traditional year-round grazing system on the QTP.

Effects of microbial inoculants on the fermentation characteristics and microbial communities of sweet sorghum bagasse silage

Sweet sorghum bagasse (SSB) is a promising raw material for silage fermentation due to its high residual nutritive, but the efficient fermentation strategy of SSB has not been reported yet. This study evaluated the effects of microbial inoculant on the fermentation quality, chemical composition and microbial community of SSB silage. The silage inoculated with isolated lactic acid bacteria (LpE) achieved better fermentation than that of commercial inoculant A, B (CIA, CIB) and untreatment, including low pH value, high levels of lactic acid and water soluble carbohydrates (WSC) content, which demonstrated that the LpE inoculant could contribute to the preservation of nutrition and the manipulation of fermentation process of SSB. In addition, the results of microbial community analysis indicated that the LpE inoculant significantly changed the composition and diversity of bacteria in SSB silage. After ensiling, the LpE inoculated silage were dominated by Lactobacillus(95.71%), Weissella(0.19%). These results were of great guiding significance aiming for high-quality silage production using SSB materials on the basis of target-based regulation methods.

Silage fermentation and ruminal degradation of cassava foliage prepared with microbial additive

To effectively utilize the tropical cassava (Manihot esculenta Crantz) foliage (CF) resources, the CF silages were prepared with microbial additives, including Chikuso-1 (CH1, Lactobacillus plantarum), Snow Lact L (SN, L. rhamnosus), Acremonium cellulase (CE), SN + CE and CH1 + CE. Silage fermentation, chemical composition and ruminal degradation were studied in Hainan, China. CF silages prepared with lactic acid bacteria (LAB) and CE were well preserved, with a higher (P < 0.05) lactic acid, a lower (P < 0.05) pH value, butyric acid content and NH3-N ⁄ total-N compared with the controls. The additive-treated silages showed increased crude protein (CP) content, but decreased (P < 0.05) NDF and ADF contents. Meanwhile, the additive treatment improved relative feed value and ruminal degradability of dry matter (DM), CP, neutral detergent fiber and acid detergent fiber. In addition, the combination of LAB and CE resulted in better fermentation quality and ruminal degradability compared with LAB or CE single treatment. The results demonstrated that the CF could be prepared as ruminant feed, and the combination of LAB and CE might exert beneficial synergistic effect on silage fermentation.

Ensiling characteristics, in vitro rumen fermentation, microbial communities and aerobic stability of low-dry matter silages produced with sweet sorghum and alfalfa mixtures

BACKGROUND

Silages produced with grass and legume mixtures may have positive associative effects on silage quality and animal performance when ruminants are fed the silages. The present study aimed to determine the preservation characteristics, in vitro rumen fermentation profile and microbial abundance of silages, produced with mixtures of sweet sorghum (SS) and alfalfa (AF) in different ratios: 100:0 (Control), 75:25 (SA25), 50:50 (SA50), 25:75 (SA75) and 0:100 (SA100) on a fresh weight basis.

RESULTS

As the proportion of AF increased in the silages, pH, acetic acid, ammonia nitrogen and crude protein (CP) concentrations, and aerobic stability increased (P < 0.05), whereas lactic acid and neutral detergent fibre (NDF) and acid detergent fibre (ADF) concentrations decreased (P < 0.05). Increasing the proportion of AF in the silages, increased (P < 0.05) the in vitro degradability of dry matter and CP, as well as the proportions of genus Prevotella, but decreased (P < 0.05) the in vitro degradability of NDF (IVNDFD) and ADF (IVADFD) and proportions of Butyrivibrio fibrisolvens. Compared to the Control silage, SA25 silage had greater (P < 0.05) proportions of Fibrobacter succinogenes and Ruminococcus flavefaciens, IVNDFD, IVADFD, ruminal short chain fatty acids and microbial protein concentrations, as well as lower (P < 0.05) methane production.

CONCLUSION

The silage produced with the SS to AF ratio of 75:25 was the most suitable for ruminants use as a result of the optimal balance of fermentation quality, feed-nutritional value and aerobic stability. © 2018 Society of Chemical Industry.

Microbial communities and natural fermentation of corn silages prepared with farm bunker-silo in Southwest China

This study analyzed the variation of microbial communities, their achieved fermentation quality, and the association between microbial diversity and environmental factors after ensiling of 96 samples prepared with bunker-silo in Southwest China. Most of natural corn silages achieved good fermentation, e.g., low pH value (<4.2) and high levels of lactic acid (36.26-79.83 mg/g DM). Weissella species were the dominant epiphytic bacteria in raw material, while Lactobacillus and Acetobacter species were prevalent in silages. Natural Lactobacillus and Pediococcus species produced more lactic acid during ensiling, while the production of acetic acid was highly positively correlated with both Acetobacter and Bradyrhizobium species. Rainfall and humidity affected community of epiphytic bacteria on the corn material, and the temperature affected richness of bacterial species during ensiling. The results confirmed that microbial community of silages in hot and humid area is unique and climatic factors ultimately affect the fermentation quality through influencing microbial community.

Effects of applying oil-extracted microalgae on the fermentation quality, feed-nutritive value and aerobic stability of ensiled sweet sorghum

BACKGROUND

A laboratory-silo study was conducted to evaluate the fermentation quality, feed-nutritive value and aerobic stability of sweet sorghum silage with or without oil-extracted microalgae supplementation. Sweet sorghum was mixed with four microalgae levels (0%, 1%, 2% and 3% on a dry matter basis; control, M1, M2 and M3, respectively) and ensiled for 45 d. Further, the four experimental silages were subjected to an aerobic stability test lasting 7 d.

RESULTS

All the silages except M3 silage had good fermentative characteristics with low pH and ammonia nitrogen concentrations, and high lactic acid concentrations and favorable microbial parameters. Meanwhile, oil-extracted microalgae supplementation improved the feed-nutritional value of sweet sorghum silage. Fibre (neutral detergent fibre, acid detergent fibre, acid detergent lignin and cellulose) concentrations decreased, while dry matter and crude protein levels markedly increased (P < 0.05). Compared with the control (69.7 h), treatments M2 and M3 improved the aerobic stability of sweet sorghum silage by 43.8% and more than 143% respectively, and decreased the clostridia spore counts during the stage of air exposure.

CONCLUSION

Sweet sorghum silage produced with 2% oil-extracted microalgae addition was the most suitable for animal use due to the optimal balance of fermentation quality, feed-nutritional value and aerobic stability, which merits further in vivo studies using grazing ruminants. © 2018 Society of Chemical Industry.

Effects of genotype, wilting, and additives on the nutritive value and fermentation of bermudagrass silage

Bermudagrass is the main warm-season grass species used for livestock production in the southeastern United States; however, when it is ensiled, the silage fermentation parameters are often less than desirable. The objective of this study was to investigate the effects of management practices on the nutritive value and fermentation characteristics of bermudagrass silage. In Exp. 1, treatments were the factorial combinations of 2 bermudagrass genotypes, 'Jiggs' () and 'Tifton 85' ( sp.), 4 additives, and 2 DM concentrations at ensiling. The additives were 1) untreated control (deionized water), 2) Ecosyl, 3) B500, or 4) sugarcane molasses. The 2 DM concentrations at ensiling were low DM (22% DM) or high DM (53% DM). Treatments were replicated 3 times in a completely randomized design. Silage treated with molasses had a lesser ( < 0.05) pH and greater ( < 0.01) lactate concentrations than the control, Ecosyl, and B500 in silage with low DM concentrations and greater ( < 0.01) in vitro true digestibility (IVTD) and lesser ( < 0.01) ADF concentrations than the other treatments at either DM concentration. Silage treated with B500 had the greatest ( < 0.01) aerobic stability, whereas that treated with molasses had the least aerobic stability. However, all treatments presented long aerobic stability (≥150 h). Jiggs had lesser ( < 0.01) ADF and NDF and NDF digestibility (NDFD) concentrations than Tifton 85 and Tifton 85 had greater ( < 0.01) IVTD than Jiggs in the silage with a high DM concentration. In Exp. 2, Jiggs silage treated with either molasses (20 g molasses [DM]/kg forage [as-fed basis]) or nothing (control, untreated silage) was fed to 16 beef heifers ( sp.) in individual drylot pens in a completely randomized design with 8 replicates for voluntary DMI, in vivo apparent DM digestibility, and NDFD evaluations. There were no differences ( = 0.36) among treatments in NDFD; however, there was a trend ( < 0.08) for greater in vivo apparent DM digestibility and DMI in heifers fed the molasses-treated silage. Microbial inoculants had decreased effects on Jiggs and Tifton 85 bermudagrass silage ensiled at a low DM concentration; however, adding molasses was an effective management practice to improve its nutritive value and fermentation characteristics.

Silage fermentation and ruminal degradation of stylo prepared with lactic acid bacteria and cellulase

In order to improve the silage fermentation of stylo (Stylosanthes guianensis) in tropical areas, stylo silages were prepared with commercial additives Lactobacillus plantarum Chikuso-1 (CH1), L. rhamnasus Snow Lact L (SN), Acremonium cellulase (CE) and their combination as SN+CE or CH1 + CE, and the fermentation quality, chemical composition and ruminal degradation of these silages were studied. Stylo silages treated with lactic acid bacteria (LAB) or cellulase, the pH value and NH₃ -N ⁄ total-N were significantly (P < 0.05) decreased while the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (aNDFom) and acid detergent fiber (ADFom) were significantly (P < 0.05) increased compared to control. Compared to LAB or cellulase-treated silages, the DM, CP contents and relative feed value (RFV), and the ruminal degradability in LAB plus cellulase-treated silages were significantly (P < 0.05) higher, but the aNDFom content was significantly (P < 0.05) lower. CH1 + CE treatment was more effective in silage fermentation and ruminal degradation than SN+CE treatment. The results confirmed that LAB or LAB plus cellulase treatment could improve the fermentation quality, chemical composition and ruminal degradation of stylo silage. Moreover, the combined treatment with LAB and cellulase may have beneficial synergistic effects on ruminal degradation.

Effects of calcium propionate on the fermentation quality and aerobic stability of alfalfa silage

Objective

To assess the potency of calcium propionate (CAP) used as silage additive, an experiment was carried out to evaluate the effect of CAP on the nitrogen transformation, fermentation quality and aerobic stability of alfalfa silages.

Methods

Alfalfa was ensiled with four levels of CAP (5, 10, 15, and 20 g/kg of fresh weight [FW]) in laboratory silos for 30 days. After opening, the silages were analyzed for the chemical and microbiological characteristics, and subjected to an aerobic stability test.

Results

The increasing proportion of CAP did not affect pH, lactic acid (LA) concentrations and yeast counts, while linearly decreased counts of enterobacteria (p = 0.029), molds (p<0.001) and clostridia (p<0.001), and concentrations of acetic acid (p<0.001), propionic acid (p<0.001), butyric acid (p<0.001), and ethanol (p = 0.007), and quadratically (p = 0.001) increased lactic acid bacteria counts. With increasing the proportion of CAP, the dry matter (DM) loss (p<0.001), free amino acid N (p<0.001), ammonia N (p = 0.004), and non-protein N (p<0.001) contents were linearly reduced, whereas DM (p = 0.048), water soluble carbohydrate (p<0.001) and peptide N (p<0.001) contents were linearly increased. The highest Flieg’s point was found in CAP10 (75.9), represented the best fermentation quality. All silages treated with CAP improved aerobic stability as indicated by increased stable hours compared with control.

Conclusion

The addition of CAP can suppress the undesirable microorganisms during ensiling and exposure to air, thereby improving the fermentation quality and aerobic stability as well as retarding the proteolysis of alfalfa silage. It is suggested that CAP used as an additive is recommended at a level of 10 g/kg FW.

Effects of sodium diacetate on the fermentation profile, chemical composition and aerobic stability of alfalfa silage

Objective

The objective of this study was to evaluate the effect of sodium diacetate (SDA) on fermentation profile, chemical composition and aerobic stability of alfalfa (Medicago sativa L.) silage.

Methods

Fresh alfalfa was ensiled with various concentrations of SDA (0, 3, 5, 7, and 9 g/kg of fresh forage). After 60 days of the ensiling, the samples were collected to examine the fermentative quality, chemical composition and aerobic stability.

Results

The application of SDA significantly (p<0.05) decreased silage pH with the lowest value in silage with 7 g/kg of SDA. The proliferations of enterobacteria, yeasts, molds and clostridia were inhibited by SDA, resulted in lower ethanol, propionic and butyric acid concentrations and dry matter loss in SDA treated silages than control. The increasing SDA linearly decreased free amino acid N (p<0.001), ammonia N (p = 0.018) and non-protein N (p<0.001), while linearly increased water soluble carbohydrate (p<0.001) and peptide N (p<0.001). It is speculated that SDA accelerated the shift from homofermentative to heterofermentative lactic acid bacteria during the silage fermentation, indicated by lower lactic acid production in SDA-9 than SDA-7 silages after 60 days of ensiling. Alfalfa silages treated with SDA at 7 g/kg had highest Flieg’s point and remained stable more than 9 d during aerobic exposure under humid and hot conditions in southern China.

Conclusion

SDA may be used as an additive for alfalfa silages at a level of 7 g/kg.