• Asian-Australasian Journal of Animal Sciences
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• v.32 no.1
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• pp.92-102
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• 2019

Objective: To investigate changes in rumen fermentation characteristics and bacterial community by a sudden change to a high concentrate diet (HC) in Korean domestic ruminants. Methods: Major Korean domestic ruminants (each of four Hanwoo cows; $545.5{\pm}33.6kg$, Holstein cows; $516.3{\pm}42.7kg$, and Korean native goats; $19.1{\pm}1.4kg$) were used in this experiment. They were housed individually and were fed ad libitum with a same TMR (800 g/kg timothy hay and 200 g/kg concentrate mix) twice daily. After two-week feeding, only the concentrate mix was offered for one week in order to induce rapid rumen acidosis. The rumen fluid was collected from each animals twice (on week 2 and week 3) at 2 h after morning feeding using an oral stomach tube. Each collected rumen fluid was analyzed for pH, volatile fatty acid (VFA), and $NH_3-N$. In addition, differences in microbial community among ruminant species and between normal and an acidosis condition were assessed using two culture-independent 16S polymerase chain reaction (PCR)-based techniques (terminal restriction fragment length polymorphism and quantitative real-time PCR). Results: The HC decreased ruminal pH and altered relative concentrations of ruminal VFA (p<0.01). Total VFA concentration increased in Holstein cows only (p<0.01). Terminal restriction fragment length polymorphism and real-time quantitative PCR analysis using culture-independent 16S PCR-based techniques, revealed rumen bacterial diversity differed by species but not by HC (p<0.01); bacterial diversity was higher in Korean native goats than that in Holstein cows. HC changed the relative populations of rumen bacterial species. Specifically, the abundance of Fibrobacter succinogenes was decreased while Lactobacillus spp. and Megasphaera elsdenii were increased (p<0.01). Conclusion: The HC altered the relative populations, but not diversity, of the ruminal bacterial community, which differed by ruminant species.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.348-352
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• 2005

In this study, fermentation using a rotary biofilm contactor was conducted to improve bacterial cellulose production. We investigated the optimal fermentation conditions by using a newly isolated Gluconacetobacter sp. RKY5 in the rotary biofilm contactor. The optimal total area of discs was found to be 1,769 $cm^2$ at which bacterial cellulose and cell concentration was obtained to 5.52 g/L and 4.98 g/L, respectively. In case of aeration experiment, when the aeration rate was 1.25 vvm, the maximal bacterial cellulose (5.67 g/L) was obtained and cell concentration was 5.25 g/L.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1482-1488
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• 2002

The aim of this study was to explore the effects of fiber sources on gut development and bacterial activity in the gastrointestinal tract of piglets. Eighteen crossbred (Duroc${\times}$Landrace${\times}$Yorkshire) barrows were fed a basal diet based on corn plus soybean meal or similar diets in which a portion of the corn and soybean was replaced by 5% wheat bran or 5% sugar beet pulp. The results indicate that pigs fed diets containing 5% wheat bran or 5% sugar beet pulp had lower liver weights than control pigs (p<0.01). The relative weight of the pancreas in pigs fed diets containing 5% sugar beet pulp was greater than that of control pigs or pigs fed diets containing 5% wheat bran (p<0.05). The pH of the ileal digesta of pigs fed the diet containing 5% wheat bran was higher than that of control pigs or pigs fed the diet containing 5% sugar beet pulp (p<0.05). The lipase activity in the distal jejunum, proximal, and distal ileum of pigs fed the control diet was higher than that of pigs fed the diets containing 5% wheat bran or 5% sugar beet pulp (p<0.05). The concentration of volatile fatty acids anterior to the caecum was greater for the pigs fed the diet containing 5% sugar beet pulp, while the concentration of volatile fatty acids posterior to the ileum was greater for the pigs fed the diet containing 5% wheat bran. This means that sugar beet pulp increased the bacterial fermentation precaecum, while wheat bran increased the bacterial fermentation post-ileum. The concentration of bacterial nitrogen and bacterial protein/total protein in ileal digesta of pigs fed the control diet was higher (p<0.05) than that of pigs fed the diets contained either fiber source. Bacterial protein/total protein in the feces of pigs fed the diet containing 5% sugar beet pulp was higher than that of pigs fed the control diet. This means that inclusion of 5% wheat bran or sugar beet pulp in diets influenced the development of the digestive tract of piglet. The mechanism by which dietary fiber reduced specific activity of lipase needs further consideration. Dietary fiber influenced the bacterial activity in the digestive tract of piglets, sugar beet pulp increased the fermentation in the upper gastrointestinal tract, and while wheat bran increased the fermentation in the lower gastrointestinal tract.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.7
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• pp.901-906
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• 2010

The improvement of the fermentation quality of rice straw silage by application of lactic acid bacteria (LAB) and glucose was investigated in this study. Sixteen rice varieties were harvested at the maturity stage and the rice straw was ensiled with LAB inoculant ($1{\times}10^5$ cfu/g of fresh weight) and glucose (2% of fresh weight). Inoculation with LAB improved the fermentation as reflected in reductions in pH, acetic acid (by 3.7 to 78.3%), butyric acid (by -6.0 to 100.0%) and ammonia nitrogen (by 1.0 to 71.7%) concentrations, and increases in lactic acid (by 43.9 to 282.9%) and crude protein concentrations compared with the control. Application of LAB plus glucose was more effective in improving fermentation quality than LAB alone. The variety of rice straw which contained relatively high levels of water soluble carbohydrates (WSC) tended to obtain better fermentation quality. The results suggested that LAB application and selection of rice varieties whose straw contained high levels of WSC were effective in improvement of the fermentation quality of rice straw silage.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.648-658
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• 2016

Preservation of fresh algae plays an important role in algae seed subculture and aquaculture. The determination and examination of the changes of cell viability, composition, and bacterial species during storage would help to take suitable preservation methods to prolong the preservation time of fresh algae. Nostoc flagelliforme is a kind of edible cyanobacterium with important herbal and dietary values. This article investigated the changes of bacterial species and biochemical characteristics of fresh N. flagelliforme concentrate during natural storage. It was found that the viability of cells decreased along with the storage time. Fourteen bacteria strains in the algae concentrate were identified by PCR-DGGE and were grouped into four phyla, including Cyanobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Among them, Enterococcus viikkiensis may be a concern in the preservation. Eleven volatile organic compounds were identified from N. flagelliforme cells, in which geosmin could be treated as an indicator of the freshness of N. flagelliforme. The occurrence of indole compound may be an indicator of the degradation of cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.766-772
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• 1999

In order to improve funtionality of kochujang, red ginseng powder(1, 2 and 5% red ginseng on the total weight basis) was added to the raw material of kochujang. Changes in moisture content, microflora and enzyme activities were investigated in control kochujang(Sunchang kochujang) and red ginseng added kochujang during fermentation at 25oC for 120 days. Kochujang samples fremented for 90 and 120 days were subjected to sensory evaluation test. As the fermentation progressed, the moisture content and titratable acidity were gradually increased whereas pH was decreased. However, red ginseng had no effects on those changes. Bacterial count was maintained at the level of 107 CFU/g during fermentation. The level of yeast count was 104 CFU/g at the early stage of fermentation and increaed to 107 CFU/g after 60 days of fermentation and then maintained at 107 CFU/g. Red-ginseng had no effects on bacterial and yeast counts of kochujang. Amylase activity was gradually reduced during fermentation. Amylase activity was increased until 60 days of fermentation and then reduced by 90 days of fermentation. Acidic protease activity was slightly reduced at the initial stage of fermentation and then rapid increased. Acidic protease activity was at the highest level after 120 days of fermentation. Red ginseng did not alter those enzyme activities of kochujang. There were no differences in sensory properties between kochujang samples fermented for 90 and 120 days of fermentation. The addition of red-ginseng did not affect such sensory properties of kochujang as color, odor, hot taste and salty taste, but overall preference appeared to be improved by red ginseng addition.

• Journal of Life Science
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• v.33 no.6
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• pp.481-489
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• 2023

The taste and quality of soy sauce, a fermented liquid condiment, is greatly influenced by microbial metabolism during fermentation. To investigate the microbiological characteristics of ganjang during the initial fermentation process, we prepared meju (fermented soybean) blocks fermented with starter cultures and solar salts and analyzed the microbial community quantitively using 16S rRNA gene profiling from ganjang that had been fermented over a five-week period. The ganjang samples were collected and analyzed after soaking for week one (1W), three (3W), and five (5W) weeks. We found that Halomonadaceae was significantly higher in the 1W group (89.83%) than the 3W and 5W groups (14.46%, and 13.78%, respectively). At a species level, Chromohalobacter beijerinckii and Chromohalobacter canadensis were the dominant species in the 1W group but several taxa such as Bacillus subtilis, Pediococcus acidilactici, and Enterococcus faecalis were more abundant in the 3W and 5W groups. Pearson correlation analysis of the relative abundance of the bacteria showed a negative correlation between Chromohalobacter and two bacterial genera Bacillus and Enterococcus. Beta-diversity showed a statistical distinction between the 1W and the 3W and 5W groups, while no significance was evident between the 3W and 5W groups. Linear discriminant effect size analysis was used to identify biomarkers and significant differences in the relative abundance of several halophilic bacteria, Bacillus sp. and lactic acid bacteria at 1W, 3W, and 5W, recpectively, which indicates the important role of the bacterial community at these time points.

• Animal Bioscience
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• v.37 no.2
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• pp.261-273
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• 2024

Objective: The objective of this study was to evaluate the growth performance, rumen fermentation parameters and bacterial community of post-weaning dairy calves in response to five diets varying in corn silage (CS) inclusion. Methods: A total of forty Holstein weaned bull calves (80±3 days of age;128.2±5.03 kg at study initiation) were randomized into five groups (8 calves/group) with each receiving one of five dietary treatments offered as total mixed ration in a 123-d feeding study. Dietary treatments were control diet (CON; 0% CS dry matter [DM]); Treatment 1 (T1; 27.2% CS DM); Treatment 2 (T2; 46.5% CS DM); Treatment 3 (T3; 54.8% CS DM); and Treatment 4 (T4; 67.2% CS DM) with all diets balanced for similar protein and energy concentration. Results: Results showed that calves offered CS had greater average daily gain, body length and chest depth growth, meanwhile altered rumen fermentation indicated by decreased rumen acetate concentrations. Principal coordinate analysis showed the rumen bacterial community structure was affected by varying CS inclusion diets. Bacteroidetes and Firmicutes were the predominant bacterial phyla in the calf rumens across all treatments. At the genus level, the abundance of Bacteroidales_RF16_group was increased, whereas Unclassified_Lachnospiraceae was decreased for calves fed CS. Furthermore, Spearman's correlation test between the rumen bacteria and rumen fermentation parameters indicated that Bacteroidales_RF16_group and Unclassified Lachnospiraceae were positively correlated with propionate and acetate, respectively. Conclusion: The results of the current study suggested that diet CS inclusion was beneficial for post-weaning dairy calf growth, with 27.2% to 46.5% CS of diet DM recommended to achieve improved growth performance. Bacteroidales_RF16_group and Unclassified Lachnospiraceae play an important role in the rumen fermentation pattern for post-weaning calves fed CS.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.26-32
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• 1990

Attempts were made to define the characteristics of microbial community as an indicator of Kimchi fermentation. Determination of communities was carried out by simple Gram-stain, followed by direct microcopic counts. In room-temperature $(15^{\circ}C)$ fermentation, microbial succession was occurred in the order of communities of Gram-positive bacteria, yeasts and Gram-negative bacteria. It was characteristic that Gram-positive bacterial community was developed during the production of lactic acid, yeasts community was developed to cause rancidity, and Gram-negative bacterial community was relevant to maceration (or softening) as well as rancidity. The fluctuation of apparent Gram-negative reaction group might be used as a criterion of death or aging of Gram-positive bacterial populations. In low-temperature fermentation $(5^{\circ}C)$, however, it was found that yeasts and Gram-negative bacterial communities did not developed but only Gram-positive bacterial community did. It follows from these results mentioned above that maturity of Kimchi depends on the development of Cram-positive bacterial community. Thus, the size and occurrence of microbial community are avaiable for an indicator of Kimchi fermentation, and also determination of community could be a useful method to predict the maturity.

• Animal Bioscience
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• v.34 no.11
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• pp.1784-1793
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• 2021

Objective: An experiment was conducted to evaluate the effects of bamboo leaf extract (BLE) on the production performance, rumen fermentation parameters, and rumen bacterial communities of heat-stressed dairy cows. Methods: The experiment comprised a 14-day adaptation period and a 21-day experimental period and was conducted in a high-temperature and humidity environment (daily mean ambient temperature = 33.5℃±1.3℃; daily mean relative humidity = 64.9%±0.8%, daily mean temperature-humidity index = 86.2±0.4). Twelve Holstein dairy cows were randomly allocated into two groups. A total mixed ration supplemented with BLE at 0 (CON) and 1.3 g/kg dry matter (DM) were fed, respectively. Feed intake and milk yield were recorded daily. Milk samples were collected on 1, 11, and 21 d of the experimental period to analyze milk performance. Rumen fluid samples were collected on 21 d of the experimental period to analyze rumen fermentation parameters and rumen bacterial communities. Results: Compared with the control group, supplementation of BLE increased milk yield (p<0.01), milk fat yield (p = 0.04), 4% fat-corrected milk (p<0.01) and milk fat content (p<0.01); reduced somatic cell count (p<0.01). No differences in DM intake and milk protein or lactose content were observed between two groups. Supplementation of BLE also increased the rumen total volatile fatty acid (p<0.01), acetate (p<0.01), butyrate (p<0.01), and valerate (p = 0.05) concentrations. However, no significant effects were observed on rumen pH, ammonia nitrogen, propionate, acetate/propionate ratio, isobutyrate, or isovalerate. Furthermore, BLE increased the rumen bacterial abundance and the diversity of the rumen bacterial community. The BLE reduced the Firmicutes/Bacteroidetes abundance ratio and increased the abundances of Butyrivibrio_2 (p<0.01) and Ruminococcus_2 (p<0.01). Conclusion: The BLE supplementation at 1.3 g/kg DM could improve production performance and rumen fermentation in dairy cows during heat stress.