• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1521-1527
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• 2019

Objective: To study the contribution of plant enzyme and microbial activities on protein degradation in silage, this study evaluated the nitrogen transformation dynamics during ensiling of non- and irradiated alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.). Methods: Alfalfa and red clover silages were prepared and equally divided into two groups. One group was exposed to ${\gamma}$-irradiation at a recommended dosage (25 Gky). Therefore, four types of silages were produced: i) non-irradiated alfalfa silage; ii) irradiated alfalfa silage; iii) non-irradiated red clover silage; and iv) irradiated red clover silage. These silages were opened for fermentation quality and nitrogen components analyses after 1, 4, 8, and 30 days, respectively. Results: The ${\gamma}$-irradiation successfully suppressed microbial activity, indicated by high pH and no apparent increases in fermentation end products in irradiated silages. All nitrogen components, except for peptide-N, increased throughout the ensiling process. Proteolysis less occurred in red clover silages compared with alfalfa silages, indicated by smaller (p<0.05) increment in peptide-N and free amino acid N (FAA-N) during early stage of ensiling. The ${\gamma}$-irradiation treatment increased (p<0.05) peptide-N and FAA-N in alfalfa silage at day 1, whereas not in red clover silage; these two nitrogen components were higher (p<0.05) between day 4 and day 30 in non-irradiated silages than the irradiated silages. The ammonia nitrogen and non-protein nitrogen were highest in non-irradiated alfalfa silage and lowest in irradiated red clover silage after ensiling. Conclusion: The result of this study indicate that red clover and alfalfa are two forages varying in their nitrogen transformation patterns, especially during early stages of ensiling. Microbial activity plays a certain role in the proteolysis and seems little affected by the presence of polyphenol oxidase in red clover compared with alfalfaa.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1273-1278
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• 2005

This study is to evaluate the effect of different levels of ensiling density on the fermentation quality of guineagrass silages during the early stage of ensiling. Guineagrass at the milky ripe stage was chopped and ensiled into a small-scale laboratory silo at two ensiling density levels (high density at 95 g/silo and low density at 75 g/silo). Three silos per level were opened after six ensiling periods (0.5, 1, 1.5, 2, 3 and 7 days of ensiling) and the fermentation qualities were analyzed. Within the initial 1.5 days of ensiling there were not significant (p>0.05) differences in the fermentation qualities between two density levels silages, and an almost constant pH and no or only small amounts of lactic acid, acetic acid and total volatile fatty acids were detected. However, the high density silage significantly (p<0.05) increased the rate and extent of fermentation after 1.5 days of ensiling, which was well reflected in significantly (p<0.05) faster and larger pH decline and lactic acid production at each elapsed time as compared with the low density silage. This resulted in significantly (p<0.05) lower finial pH and significantly (p<0.05) higher lactic acid content at the end of the experiment. Moreover, there was higher AA content relative to LA in both the H-D and L-D silages during the full fermentation course, and resulted in the AA-type silage. There were generally somewhat or significantly (p<0.05) higher acetic acid, volatile fatty acids and ammonia-N/total nitrogen in the high density silage than in the low density silage during the initial 3 days of ensiling. However, there were higher (p>0.05) ammonia-N/total nitrogen and significantly (p<0.05) higher butyric acid content in the low density silage at day 7 of ensiling. The silages of two density levels showed an initial increase in glucose between 0.5 and 1 day for the high density silage and between 1 and 1.5 days for the low density silage, respectively, thereafter showed a large decrease until the end of the experiment. There were not large differences (p>0.05) in ethanol content between the low density and high density silages that showed small amounts within initial 3 days of ensiling. However, the low density silage had a significantly (p<0.05) higher ethanol content than the high density silage at the end of experiment. From the above results it was suggested that the increase in ensiling density was an effective method to improve the fermentation quality, especially for tropical grasses.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.213-217
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• 2002

This study determined the influence of moisture, ensiling time and their interactions on the losses of hemicellulose and cellulose during ensiling of orchardgrass. Orchardgrass containing 80 (HM), 70 (MM) and 55% (LM) moisture was ensiled in 3 laboratory silos of 500 ml capacity for 3, 7, 21 and 91 days. The dry matter (DM), water-soluble carbohydrates (WSC), hemicellulose and cellulose contents of the ensiled orchardgrass was lowered than that of the untreated grass regardless of moisture content. Ensiling orchardgrass for 91 days (d) decreased (p<0.01) hemicellulose contents from 19 to 15%, 20 to 15% and 18 to 12% and cellulose from 31 to 29%, 29 to 26% and 27 to 26% for LM, MM and HM silage, respectively. Results from fermentation of LM and MM silages were within acceptable guidelines except for butyric acid and ammonia after 3 weeks of ensiling of MM which appeared to be lower than ideal. The results of the fermentation of HM silages were poor showing higher concentration of acetic, propionic and butyric acids and traces of isovaleric, valeric and caproic acids with ammonia at all stage of time. While the DM losses from LM and MM silages over the ensiling period were acceptable, that for HM silage increased to 13% after 91 d ensiling, confirming a poor fermentation process occurred. The greatest WSC losses occurred within 7 d of ensiling and the lowest losses occurred after 3 weeks of ensiling. Except in HM silage, the hemicellulose and cellulose losses were highest (p<0.01) in the first 3 weeks of ensiling. Hemicellulose losses were between 19 and 22% and 4.2 and 5.9% up to 3 weeks and after 3 weeks of ensiling LM and MM silages, respectively. Cellulose losses were small. In contrast, hemicellulose losses after 3 weeks of ensiling of HM silage was about 50% higher than over the first 3 weeks possibly due to clostridial type fermentation. The results showed that increasing ensiling time of high moisture orchardgrass would result in the excessive losses of DM, WSC, hemicellulose and cellulose in the silage.

• Animal Bioscience
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• v.35 no.8
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• pp.1162-1173
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• 2022

Objective: This study aimed to investigate the fermentation profiles, bacterial community and predicted metabolic characteristics of Sudangrass (Sorghum sudanense Stapf.) during ensiling. Methods: First-cutting Sudangrass was harvested at the vegetative stage and ensiled in laboratory-scale silos (1 L capacity). Triplicate silos were sampled after 1, 3, 7, 15, 30, and 60 days of ensiling, respectively. The bacterial communities on day 3 and 60 were assessed through high-throughput sequencing technology, and 16S rRNA-gene predicted functional profiles were analyzed according to the Kyoto encyclopedia of genes and genomes using Tax4Fun. Results: The Sudangrass silages showed good fermentation quality, indicated by higher lactic acid contents, and lower pH, butyric acid and ammonia nitrogen contents. The dominant genus Lactococcus on day 3 was replaced by Lactobacillus on day 60. The metabolism of amino acid, energy, cofactors and vitamins was restricted, and metabolism of nucleotide and carbohydrate was promoted after ensiling. The 1-phosphofructokinase and pyruvate kinase of bacterial community seemed to play important roles in stimulating the lactic acid fermentation, and the promotion of arginine deiminase could help lactic acid bacteria to tolerate the acidic environment. Conclusion: High-throughput sequencing technology combined with 16S rRNA gene-predicted functional analyses revealed the differences during the early and late stages of Sudangrass ensiling not only for distinct bacterial community but also for specific functional metabolites. The results could provide a comprehensive insight into bacterial community and metabolic characteristics to further improve the silage quality.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.1
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• pp.62-72
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• 2016

This study investigated the dynamics associated with prolonged ensiling and aerobic deterioration of whole crop corn (WCC) silages and total mixed ration (TMR) silages containing WCC (C-TMR silages) to clarify the differences that account for the enhanced aerobic stability of TMR silages. Laboratory-scale barrel silos were randomly opened after 7, 14, 28, and 56 d of ensiling and were subjected to analyses of fermentation quality, microbial and temperature dynamics during aerobic exposure. WCC and C-TMR silages were both well preserved and microorganisms were inhibited with prolonged ensiling, including lactic acid bacteria. Yeast were inhibited to below the detection limit of 500 cfu/g fresh matter within 28 d of ensiling. Aerobic stability of both silages was enhanced with prolonged ensiling, whereas C-TMR silages were more aerobically stable than WCC silages for the same ensiling period. Besides the high moisture content, the weak aerobic stability of WCC silage is likely attributable to the higher lactic acid content and yeast count, which result from the high water-soluble carbohydrates content in WCC. After silo opening, yeast were the first to propagate and the increase in yeast levels is greater than that of other microorganisms in silages before deterioration. Besides, increased levels of aerobic bacteria were also detected before heating of WCC silages. The temperature dynamics also indicated that yeast are closely associated with the onset of the aerobic deterioration of C-TMR silage, whereas for WCC silages, besides yeast, aerobic bacteria also function in the aerobic deterioration. Therefore, the inclusion of WCC might contribute to the survival of yeast during ensiling but not influence the role of yeast in deterioration of C-TMR silages.

• Animal Bioscience
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• v.34 no.1
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• pp.56-65
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• 2021

Objective: This study was conducted to investigate the effects of molasses and Lactobacillus plantarum on the ensiling quality and in vitro rumen fermentation of sudangrass silage prepared with or without wilting. Methods: The ensiling experiment, measured with 3 replicates, was carried out according to a 2×4 (wilted stages×additives) factorial treatment structure. Dry matter of the fresh (210 g/kg fresh matter) or wilted (305 g/kg fresh matter) sudangrass were ensiled (packed into 5.0-L plastic jars) without additive (control) or with molasses (M), Lactobacillus plantarum (LP), or molasses + Lactobacillus plantarum (M+LP). After 60 days of ensiling, the silages were analyzed for the chemical, fermentation, and in vitro characteristics. Results: After 60 days of ensiling, the fermentation parameters were affected by wilted, the additives and the interactions of wilted with the additives (p<0.05). The M+LP treatment at wilted had higher lactic acid levels and V-score (p<0.05) but lower pH values and butyric acid concentrations than the other treatments. In comparison with sudangrass before ensiling, after ensiling had lower dry matter and higher non-fibrous carbohydrate. The in vitro gas production, in vitro dry matter digestibility, in vitro crude protein digestibility, and in vitro acid fiber detergent digestibility changed under the effects of the additives. Significant interactions were observed between wilted and the additives in terms of in vitro gas production at 48 h, asymptotic gas production, gas production rate, half time, and the average gas production rate. The total volatile fatty acid levels in the additive treatments were higher than those in the control. Conclusion: Wilting and supplementation with molasses and Lactobacillus plantarum had the ability to improve the ensiling quality and in vitro nutrient digestibility of sudangrass silage. The M+LP treatment at wilted exhibited the strongest positive effects on silage quality and in vitro ruminal fermentation characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1727-1734
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• 2005

The fermentation characteristics and mono- and di-saccharides compositions during the early stage of ensiling were studied with a temperate grass, Italian ryegrass (Lolium multiflorum Lam.) and a tropical grass, guineagrass (Panicum maximum Jacq.). The laboratory silos were kept in the room set at 25$^{\circ}C$, and then were opened on 0.5, 1, 2, 3, 5 and 7 days (14 days in Italian ryegrass) after ensiling, respectively. The Italian ryegrass silage showed a fast and large pH decrease caused by a fast and large production of lactic acid during the first 5 days of ensiling and succeeded to achieve lactic acid type fermentation; high lactic acid/acetic acid and lactic acid content at the end of ensiling (14 days), low values of pH (3.74), acetic acid, ethanol and ammonia-N/total nitrogen, none or only small amounts of Butyric acid, valeric acid and propionic acid. The guineagrass silage showed a slow decrease in pH and a slow increase in lactic acid content during the full ensiling period, causing a high final pH value, low contents of lactic acid, acetic acid, total volatile fatty acids and total organic acids. In Italian ryegrass silage, mono- and di-saccharides compositions decreased largely within the initial 0.5 day (12 h) of ensiling. Sucrose disappeared rapidly within the initial 0.5 day of ensiling, but fructose and glucose contents showed an initial rise by the activity of enzymes in plant tissues, and then decreased gradually. On the other hand, the contents of monoand di-saccharides in guineagrass showed the largest decreases due mainly to plant respiration within the initial 0.5 day of ensiling, and no initial rises in fructose and glucose contents during the early stage of ensiling because of the absence of fructans which are hydrolyzed into fructose and glucose in temperate grasses. In both silages, the rate of reduction in mono- and di-saccharides compositions within the initial 5 days of ensiling was ranked in the order of glucose>fructose>sucrose, suggesting that glucose and fructose might be more favorably utilized than sucrose by microorganisms and glucose is the first fermentation substrate. It was concluded that the silage made from Italian ryegrass with high moisture content had a good fermentation quality owing to the dominance of lactic acid bacteria and active lactic acid fermentation during the initial stage of ensiling. These results can be explained by rapid plant sap liberation and the high activity of plant enzyme hydrolyzed fructans into fructose and glucose within the initial 2 days of ensiling, which stimulate the homofermentative lactic acid bacteria growth. In ensiling a temperate grass, the physical characteristics may ensure the rapid onset of fermentation phase, which results from the smaller losses of water-soluble carbohydrates during the initial stage of ensiling and providing sufficient water-soluble carbohydrates for lactic acid bacteria. The silage made from guineagrass with intermediate dry matter and high initial mono- and di-saccharides content was stable silage. This could be explained by the higher incorporation of air during the very early stage of ensiling and the restriction of cell breakdown and juice release due to the properties of a tropical grass with coarse porosity and stemmy structures. These physical characteristics delayed the onset of lactic acid bacteria fermentation phase by extending the phases of respiration and aerobic microorganisms activity, causing the higher loss of water-soluble carbohydrates and the shortage of lactic acid bacteria fermentation substrates.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1701-1704
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• 2001

The evaluation of structural carbohydrate losses and its effect on silages digestibility in alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) was studied during 5, 21 and 56 days ensiling. About 70 and 60 kg fresh matter of the two forages were ensiled in 9 silos of 120 L capacity. The digestion trials were conducted in two phases using the two grasses in two $4{\times}4$ Latin square design according to the four treatments being the grass and the three silages. There were no differences in the DM and CP contents resulting from 5 to 56 days ensiling in both forages. The water-soluble carbohydrates (WSC), hemicelllose, pectin, and energy were slightly reduced and appeared lower in 56 days silage. The ether extract and cellulose contents slightly increased as the ensiling process advanced in the two species. Hemicellulose losses of 29 and 41 g/kg DM were obtained in alfalfa and orchardgrass, respectively, 56 days after ensiling. While the cellulose losses in both species were very little, compared to that for hemicellulose, the pectin losses, 56 days after ensiling were 15 and 12 g/kg DM in alfalfa and orchardgras respectively. The total structural carbohydrates lost (ie., hemicellulose + cellulose + pectin) in g/kg DM of fresh material forage ensiled, is about four fifths the amount lost by WSC, in alfalfa and about two thirds, in orchardgrass, by 21 days ensiling after the activity of microorganism terminated, indicating that appreciable amount was used as substrate for silage fermentation. Ensiling alfalfa and orchardgrass for 0, 5, 21 and 56 days maintained a decreasing trend of 83.8, 82.5, 79.3 and 78.9% digestibility in alfalfa and 80.5, 77.0, 77.1 and 76.4% digestibility in orchardgrass. While the digestibility of cellulose and ether extract increased in silage in both species, the digestible energy values in silage were reduced from 2.6 to 2.3 and 2.9 to 2.7 Mcal/kg DM respectively in alfalfa and orchard during 5-56 days ensiling.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.804-810
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• 2017

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.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1606-1610
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• 2002

The dynamics of fermentation were studied with Italian ryegrass ensiled in the laboratory silos. The silos were kept in the room set at 25$^{\circ}C$, and then were opened on 0.5, 1, 2, 3, 5, 7 and 14 days after ensiling, respectively. The samples were taken from three silos at each sampling time for chemical analyses. Mono-and disaccharides composition was determined for glucose, fructose and sucrose by high performance liquid chromatography. The Italian ryegrass silage succeeded to achieve lactate type fermentation; high values of lactic acid (85.83 g/kg) and lactic acid/acetic acid at the end of ensiling (14 day), low values of pH (3.74), acetic acid (5.38 g/kg), ethanol (19.20 g/kg) and $NH_3-N/Total\;N$ (75.84 g/kg), no or only small amounts of butyric acid, valeric acid and propionic acid. The fermentation dynamics showed a fast and large pH decrease caused by a fast and large production of lactic acid during the first 5 days. Mono-and disaccharides composition largely decreased within initial 0.5 day (12 h) of ensiling. Sucrose disappeared rapidly within initial 0.5 day of ensiling, and fructose and glucose contents showed an initial rise during ensiling, and then decreased gradually. These indicated that the enzymes of plant tissue were active within 2 days of ensiling, which caused the initial rise in fructose and glucose from the hydrolysis of sucrose and fructans. After 5 days of ensilage, glucose was consumed completely, suggesting that glucose was the first fermentation substrate. After 2 days of ensiling, sum amounts of lactic acid and remaining mono-and disaccharides proved to be larger than the quantity of mono-and disaccharides in the initial grass. From the facts mentioned above, it was suggested that considerable amounts of lactic acid were produced from some other substrate such as fructans than initial mono-and disaccharides.