• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.830-835
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• 2004

An experiment of 10 weeks duration was carried out to study the influence of supplemental effective microorganism (EM) culture, yeast culture and enzymes on nutrient digestibility and gut microflora in rabbit gastrointestinal (GI) tract. Twenty four eight to nine weeks old, New Zealand White rabbits were allotted to four dietary treatments; a basal (control) feed, basal feed supplemented with either EM (1%), yeast culture or enzymes (400 ppm). Nutrient flow in digesta and their digestibility at ileum, caecum, colon and in the total tract as well as gut microflora distribution were studied. Feed dry matter was diluted from 92% to about 14% up to the ileum and about 95% of this water was reabsorbed by the colonic rectal segment followed by caecum (25%). EM and yeast improved protein digestibility at a lower rate than enzymes. Ileal, caecal, colonic and total tract digestibility of crude protein with enzymes were higher by 10.8, 9.4, 11.3 and 10.7%, respectively, as compared to the control. Yeast and enzymes increased crude fiber digestibility at ileum, caecum, colon and in the total tract by 8.5, 9.6, 9.0 and 8.3%, respectively, while EM improved them at a lower rate. Irrespective of treatments, total tract digestibility of crude protein (0.698-0.773) and fiber (0.169-0.183) were greater (p<0.05) than the ileal digestibility. Even though a post-caecal protein digestibility was observed, fiber digestion seemed to be completed in the caecum especially with yeast and enzymes. High precaecal digestibility of crude fiber (97%) and protein (95%) were observed even without additives probably due to caecotrophy. EM and yeast culture promoted the growth of lactic acid bacteria especially in the caecum but they did not influence gut yeast and mould. Present findings reveal that even though rabbits digest nutrients efficiently through hind gut fermentation, they can be further enhanced by EM, yeast and enzymes. Of the three additives tested, enzymes found to be the best.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.201-207
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• 2019

This review summarizes the studies on a wide variety of yeast found in kimchi and the effects of yeast on kimchi fermentation, and discusses the direction for further research. Yeast belongs to the genera Trichosporon, Saccharomyces, Sporisorium, Pichia, Lodderomyces, Kluyveromyces, Candida, Debaryomyces, Geotrichum, Kazachstania, Brassica, Yarrowia, Hanseniaspora, Brettanomyces, Citeromyces, Rhodotorula, and Torulopsis have been identified using culture-dependent methods and metagenomics analysis. The application of yeast as a starter into kimchi has resulted in an extension of shelf life and improvement of sensory characteristics due to a decrease in the amount of lactic acid. On the other hand, some yeast cause kimchi spoilage, which typically appears as an off-odor, texture-softening, and white-colony or white-film formation on the surface of kimchi. In contrast to lactic acid bacteria, there are limited reports on yeast isolated from kimchi. In addition, it is unclear how yeast affects the fermentation of kimchi and the mechanism by which white colony forming yeast predominate in the later stage of kimchi fermentation. Therefore, more research will be needed to solve these issues.

• Journal of Animal Environmental Science
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• v.7 no.1
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• pp.21-28
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• 2001

Optimal conditions for utilizing the slaughtered porcine blood and liver for yeast culture and the effects of the yeast cultures on the growth of broiler chicks were investigated. The quantity of yeast cultured for 24hours in the BSG medium containing blood extracts containing 5% glucose and in the LSG medium containing liver extracts containing 5% glucose were higher by 4% and 10%, respectively, than that in the YEPD medium containing 1% yeast extracts, 2% bacto pepton and 2% glucose. Optimal concentrations of ammonium sulfate supplementation to the BSG medium to increase the quantity of yeast cultured for 24 and 48 hours were 100 mM(1.3%) and 50 mM(0.65%), respectively. The optimal pH for yeast culture in BSG medium ranged from 6 to 7. One percent supplementation of either ammonium sulfate or taurine to LSG medium increased the quantity of yeast by 18% and 9%, respectively, compared to no supplementation. The body weight of chicks fed with 2% and 4% yeast culture supplementations cultivated increased at the 4th week by 10%, with relative to no supplementation. The results from this study suggest that the slaughtered porcine blood and liver can be utilized for yeast culture which is used in animal diets.

• Journal of Animal Science and Technology
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• v.44 no.3
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• pp.289-296
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• 2002

A broiler experiment was conducted to investigate the effect of supplementing yeast culture (Saccharomyces cerevisiae, Pichia pastoris) on the growth performance, small intestinal microflora and immune response in broiler chickens. One thousand hatched broiler chickens(Ross$^{(R)}$) were assigned to 6 treatments: control (basal diet), CTC; chlorotetracycline 100ppm, YC-SC; yeast culture(Saccharomyces cerevisiae) 0.3%, YC-PP; yeast culture(Pichia pastoris) 0.3%, RPPC-0.1; refined Pichia pastoris culture 0.1%, RPPC-0.3; refined Pichia pastoris culture 0.3%. There were no significant differences in growth, feed intake, feed efficiency and mortality among the treatments. However, chickens fed diets with yeast cultures showed numerically higher weight gain than those fed the control diets. Supplementation of yeast cultures and CTC improved feed efficiency and decreased mortality compared to control. Nutrient digestibilities were not affected by the dietary treatments. Total number of Lactobacilli in small intestine was higher while that of Cl. perfringens was lower with yeast culture treatments than control. Small intestine E. coli population of RPPC-0.3 treatment was significantly lower than that of the control. The serum IgG concentration tended to be higher in broilers fed yeast cultures than those fed the control and CTC diet. In conclusion, the supplementation of yeast culture products showed, although not significant but, numerical advantages in productivity and profile of microbial flora and serum IgG compared to the control and CTC supplementation.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.41-48
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• 2003

Two experiments were conducted to investigate the effect of dietary supplementation of yeast culture on the performance of broiler chicks and noxious gas emission in broiler houses. Two hundred forty and three hundred and twenty, one day old Cobb male broiler chicks in Expt 1 and Expt 2, respectively were alloted to four treatment levels of yeast culture (0, 0.1, 0.2, 0.4%). To each treatment, 60 birds were assigned in Expt 1 and 5 replicates of 16 birds each were assigned in Expt 2. Basal diets contained 21.5% and 19.0% CP, and 3,100kcal/kg ME for the starting and finishing periods, respectively. Ammonia and $CO_2$ gas emission were detected twice a day for seven days during the five week period of Expt 1. Weight gain, feed intake and feed efficiency were measured for five weeks in Expt 2. Intestinal microbes, blood cholesterol and ND antibody titer were examined at the end of Expt 2. In Expt 1, the concentration of $NH_3$ in the house of birds fed yeast culture tended to be lower than the control. It was significantly lower in the 0.4% yeast culture treatment than the control (P<0.05). $CO_2$ concentration was significantly lower in all yeast culture treatments regardless of its dietary supplemental level than the control (P<0.05). different from others. Feed efficiency (feed/gain), however, was significantly improved in all yeast culture treatments relative to that of the control for starting period (P<0.05) and that of 0.2% yeast culture treatment was significantly lower than those of the control and 0.4% for the overall period. Total number of E. coli in the ileum of birds fed yeast culture at 0.1 and 0.2% was significantly lower than those of the control and 0.4% in the ileum. The CFU of Lactobacillus spp. of birds fed yeast culture at 0.1% was higher in the cecum compared to other treatments (P<0.05). Total cholesterol level of chicks fed 0.1% yeast culture seemed to be lower compared to that of other treatments, whereas LDL-cholesterol level was significantly lower than those of the control and 0.4% treatment. ND antibody titer tended to be higher in the yeast culture treatments than the control, but was not significantly different. The results of these experiments indicated that 0.2% yeast culture may have a potential to reduce the noxious gas emission in broiler houses and maximize the performance of broiler chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.1011-1014
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• 2008

A total of 335 sows at a commercial operation (Hitch Pork Producers Inc, Guymon, OK) was used to determine dietary effects of yeast culture supplementation ($XPC^{TM}$, Diamond V Mills) on litter performance. Sows were grouped by parity (parity 1 to 12). Pigs within a group were then allotted to treatments. Treatments consisted of: CON (no added yeast culture) and YC (12 and 15 g/d XPC during gestation and lactation, respectively). Sows were housed individually and fed their assigned gestation and lactation diets from d 35 of gestation to d 21 of lactation. Sows were fed 2.0 kg/d during gestation and ad libitum during lactation. Voluntary feed intake was measured daily during lactation. At farrowing, numbers of pigs born total and alive were measured. Weights of litters were measured at birth and weaning on d 21 of lactation. Litter weight gain of the YC treatment was 6.9% greater (p<0.01) than that of the CON. However, voluntary feed intake of sows and litter size did not differ between treatments. This study indicates that dietary yeast culture supplementation benefits sow productivity by improving litter weight gain. At present, it is not confirmed if improved litter weight gain was due to milk production, which remains to be investigated.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2001.05b
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• pp.121-125
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• 2001

For the probiotic feed production, aerobic liquid fermentation of pulverized food wastes was attempted with a yeast Kluyveromyces marxianus. After grinding finely, optimal fermentation conditions of the substrate was investigated by shaking culture. The most active growth of the yeast was shown at solid content of 10%. The proper addition of urea(0.5g/l), o-phosphate(0.4g/l), molasses(4g/l), and yeast extract (1g/1) increased cell growth rate and viable cell count. For optimizing, the nutrients were all added to substrate and fermentation was carried in 2 litre jar fermenter. For the stimulation of hydrolyzing enzyme excretion, mixed culture with Aspersillus oryzae was also conducted. In 12 hours of fermentation, viable cell count of the yeast Kluyveromyces marxianus amounted to the number of 1.4 $\times$10$^{10}$ /1 in the culture medium.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.568-572
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• 2005

Saccharomyces yeast spores are more resistant to drying and storage than vegetative cells. For the mass production of yeast spores, compressed yeast was directly inoculated into a sporulation medium (SM). The effects of inoculum size and the addition of rice wine cake (RWC) into SM on the sporulation were examined using flasks. With $1\%$ inoculum of compressed yeast, $1.45{\times}10^8/ml$ of asci was obtained. The addition of $0.5\%$ RWC into SM improved the cell growth and spore yield, and the number of asci formed was $2.31{\times}10^8/ml$. The effects of culture temperature, temperature-shift, and concentrations of inoculum, potassium acetate, and RWC on the sporulation were also evaluated using a jar fermentor. The optimum temperature for spore formation was $22^{\circ}C$ where the number of asci formed was $2.46{\times}10^8/ml$. The shift of culture temperature from initial $30^{\circ}C$ for 1 day to $22^{\circ}C$ for 3 days increased the number of asci formed to $2.96{\times}10^8/ml$. The use of $2\%$ (w/v) inoculum of compressed yeast, $2\%$ potassium acetate, and $1\%$ (w/v) RWC in SM with the shift of culture temperature of initial $30^{\circ}C\;to\;22^{\circ}C$ resulted in $90\%$ sporulation ratio and formation of $6.18{\times}10^8\;asci/ml$.

• Animal Bioscience
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• v.36 no.1
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.41-49
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• 2013

In vitro and in situ incubation studies were conducted to determine effects of yeast culture supplements (Saccharomyces cerevisiae) on cellulolytic bacterial function and fiber digestion in rice straw. In vitro dry matter digestibility of rice straw gradually increased according to supplemental levels of yeast culture (0.0, 0.2, 0.4, 0.6, 0.8 and 1.0%). Digestibility of rice straw started to increase apparently when yeast culture was added more than 0.6% level (p<0.05). Also, we reconfirmed that in vitro dry matter digestibility was significantly increased by 0.6% of yeast culture addition in 4% NaOH treated and non-treated rice straws (p<0.05). When in situ dry matter digestibility was tested in Korean native goats fed basal diet or experimental diet which contained 1.0% of yeast culture, the yeast culture feeding improved in situ dry matter digestibility in both 4% NaOH treated and non-treated rice straws (p<0.05). In case of real-time PCR monitoring cellulolytic bacterial function, the bacterial population attached on rice straw showed the increasing trends with higher level of yeast culture spraying on rice straw. F. succinogenes and R. flavefaciens were significantly increased in accordance to spraying levels of yeast culture (0.0, 0.1 and 0.3%) at both 12 and 24 hrs of in situ incubation (p<0.05). R. albus was significantly higher population in yeast culture spraying than non-soraying at 12 hrs of in situ incubation (p<0.05). These bacterial populations were showed the increasing trends with digestibility enhancement of rice straw according to the higher levels of yeast culture supplement. Overall, these results clearly suggest that the presence of yeast culture result in noticeable increase of rice straw digestion, which is modulated via good effect on cellulolytic bacterial attachment to fiber substrates.