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At least 19 recordsLinked to original sources

Use of flow cytometry to monitor cell damage and predict fermentation activity of dried yeasts.

Viable dried yeast is used as an inoculum for many fermentations in the baking and wine industries. The fermentative activity of yeast in bread dough or grape must is a critical parameter of process efficiency. Here, it is shown that fluorescent stains and flow cytometry can be used in concert to predict the abilities of populations of dried bakers' and wine yeasts to ferment after rehydration. Fluorescent dyes that stain cells only if they have damaged membrane potential (oxonol) or have increased membrane permeability (propidium iodide) were used to analyse, by flow cytometry, populations of rehydrated yeasts. A strong relationship (r2 = 0.99) was found between the percentages of populations staining with the oxonol and the degree of cell membrane damage as measured by the more traditional method of leakage of intracellular compounds. There were also were good negative relationships (r2 > or = 0.83) between fermentation by rehydrated bakers' or wine dry yeasts and percentage of populations staining with either oxonol or propidium iodide. Fluorescent staining with flow cytometry confirmed that factors such as vigour of dried yeast mixing in water, soaking before stirring, rehydration in water or fermentation medium and temperature of rehydration have profound effects on subsequent yeast vitality. These experiments indicate the potential of flow cytometry as a rapid means of predicting the fermentation performance of dried bakers' and wine yeasts.

Colony Count, Microbial↗

[Effects of orally administered substances on rumen fermentation patterns in cattle (in vitro). 7. Effect of dried yeast in chronic ruminal acidosis].

The influence of dried yeast on the in-vitro-fermentation of chronic acidotic bovine rumen fluid was investigated using the longterm rumen simulation technique (RUSITEC). Five investigation periods keeping 21 days each were carried out. After a control period of eight days a five days lasting test phase followed. During this time 2 g of dried yeast were added to two reaction vessels and two reaction vessels remained as controls. The following effects of dried yeast during the investigation period on rumen fluid and rumen gas, respectively, could be noted: negligible increase of pH for 0.1 units (ns) increase of short volatile fatty acids concentrations up to 10% (p < 0.01), (acetate +1.5% [ns], propionate +6.0% [ns], i-butyrate up to +180% [p < 0.001], n-butyrate 0%, i-valerinate +39%, [p < 0.05], n-valerinate +17.6% [p < 0.001], hexanat +33% [p < 0.001]) increase of gas production up to 29% (p < 0.001) decrease of methane production up to 30% (ns) increase of hydrogen production up to 10% (ns) increase of protein concentrations up to 23% (p < 0.05) increase of ammonia concentrations up to 385% (p < 0.001). The fermentation patterns became normal during 6 days after withdrawal of the yeast.

Acidosis↗

The effect of dietary active dry yeast supplement on performance of sows during gestation-lactation and their pigs.

Thirty crossbred sows and their pigs were evaluated through two parities to determine any reproductive or growth performance effects of an active dry yeast supplement added to corn-soybean meal diets. Sow reproductive performance from d 93 of gestation through d 21 of lactation and sow milk composition were evaluated. Pig growth performance was measured from birth to 28 d after weaning. Active dry yeast was added at 0, 1, or .2% of the sow gestation diet, 0, .15, or .3% of the sow lactation diet, 0, .2, or .4% of the pig prestarter diet, 1 wk before and 1 wk after weaning, and 0, .125, or .25% during the last 3 wk in the nursery. The yeast source consisted of a concentrate of live yeast cells of the Saccharomyces cerevisiae strain containing more than 15 x 10(9) live cells/g. Sow body weight at d 93 of gestation, at farrowing, and at d 21 of lactation did not differ (P > .10) among treatment groups. Milk from sows fed active dry yeast contained higher amounts of total solids (P < .05), crude protein (P < .10), and gamma globulin (P < .06) than milk from sows fed the control diet. Sow feed intake during lactation was not affected (P > .10) by treatment, nor were there differences in litter size at birth, litter birth weight, or litter weight at d 21 after farrowing. Active dry yeast supplementation to the sow and pig diets resulted in improved postweaning pig daily gain (P < .05) and gain-to-feed ratio (P < .05) but did not affect (P > .10) feed intake. Based on these data, active dry yeast supplement during late gestation, lactation, and before and after weaning does not alter litter weight at birth or weaning but does increase gamma globulin content of sow's milk and improves postweaning rate and efficiency of weight gain of pigs.

Animals↗

Brewers dried yeast as a source of mannan oligosaccharides for weanling pigs.

Brewers dried yeast, a source of mannan oligosaccharides (MOS), was assessed as an alternative to an antimicrobial agent (carbadox) for young pigs in two experiments. The yeast contained 5.2% MOS. Agglutination tests confirmed adsorption of several serovars of E. coli and Salmonella spp. onto the yeast product. In Exp. 1, seven replicates (five pigs per pen) of 22-d-old pigs were fed a nonmedicated basal diet or the basal diet with carbadox (55 mg/kg), yeast (3%), or a combination of 3% yeast and 2% citric acid for 28 d. Carbadox did not improve growth performance. Growth rate and feed intake were depressed (P < 0.05) in pigs fed yeast alone or in combination with acid. Log counts of total coliforms, Escherichia coli, and Clostridium perfringens in feces were not affected by diet, but Bifidobacteria spp. counts were lower (P < 0.05) in pigs fed the yeast + acid diet and lactobacilli counts were higher (P < 0.05) in pigs fed yeast. Fecal pH and VFA concentrations and intestinal morphological traits were not consistently affected by diet. Serum IgG levels were elevated in the yeast + acid (P < 0.01) group. In Exp. 2, the effects of yeast and carbadox additions to the diet on enteric microbial populations in young pigs housed in isolation units were evaluated. Pigs (n = 24) were weaned at 11 d of age (4.1 kg BW) and placed in isolation chambers (two pigs per chamber) equipped with individual air filtering systems and excrement containers. Treatments were a nonmedicated basal diet and the basal diet with 55 mg/kg of carbadox or with 3% yeast. Diets were fed for 29 d, then each pig was orally dosed with approximately 9.5 x 10(8) CFU of E. coli K88. Daily fecal E. coli K88 counts were not different (P > 0.05) among treatments, but fecal shedding of carbadox-resistant coliforms was higher (P < 0.01) during the 9-d period in pigs fed carbadox. Total fecal coliforms were consistently lower throughout the postinoculation period in pigs fed yeast (P < 0.05). Yeast reduced colonization oftotal coliforms in the duodenum,jejunum, cecum, and colon, but it did not have a consistent effect on colonization of E. coli K88. Pigs fed yeast tended (P < 0.10) to have higher serum IgG levels than controls. In these experiments, brewers dried yeast and carbadox had minimal effects on growth, microbial populations, and intestinal health traits of early-weaned pigs, but certain serum immunological traits were enhanced by feeding yeast.

Agglutination Tests↗