Apparent Fermentation Research Articles

Preparation and Quality Analysis of Wine from Different Blends of Carrot-Beetroot and Carrot-Orange

ABSTRACT: One of the most popular alcoholic beverages that offers several health benefits is wine. It includes both fruit and vegetable wine and sometimes their blends. These pure and coproducts of fruits and vegetables give surprising results when tried. Beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are high in betalain and carotene, both of which have medicinal and nutritional properties. Apart from beetroot and carrot, another important fruit is orange (Citrus sinensis). It is a notable fruit known for its nourishing and restorative attributes. The fruits and vegetables used in this study (beetroot, carrot, and orange) were cleaned, peeled, and crushed to extract the juice. The juice was then fermented by mixing with yeast (Saccharomyces cerevisiae) and other ingredients such as sugar. Once fermentation was complete, various methods are used for analysis of wine like residual sugar (RS), apparent fermentation degree (AFD), fermentative capacity (FC), fermentative velocity (VC), and attenuation, etc. The vegetable-fermented wine obtained was reddish to yellow in colour, had a titratable acidity of 1.0 ±0.02 g tartaric corrosive/100 mL, was dry (with just the right amount of piece sugar), and contained between 10 and 12% alcohol. There were no discernible variations in the wine's biological components. An organoleptic analysis of the vegetable natural product wine revealed that it was palatable and thought to be reasonable for health.

Feeding Australian Acacia Gums and Gum Arabic Leads to Non-Starch Polysaccharide Accumulation in the Cecum of Rats

Exudative gums from two Australian Acacia species (A. pycnantha and A. baileyana) and gum arabic (from A. senegal) were fed to rats at graded levels (0, 20, 40, 80 g/kg), replacing cellulose in purified diets containing cholesterol plus cholic acid. Compared with consumption of the control diet containing cellulose only, consumption of the gums had no significant effects on concentrations of plasma or liver cholesterol. Plasma triacylglycerol concentrations were higher in rats fed gum arabic, whereas liver triacylglycerols were lower in rats fed the gums. The gums did not affect the total pool of volatile fatty acids in the ceca, as compared with results in controls, but did promote the relative contribution of propionate at the expense of acetate. In rats fed the diet containing cellulose (80 g/kg) the proportions of cecal acetate:propionate:butyrate were 76:15:9, whereas in the rats fed A. pycnantha gum, gum arabic and A. baileyana gum (80 g/kg) the ratios were 42:54:4, 35:46:19 and 43:53:4, respectively. The low apparent fermentability of the gums was confirmed by the accumulation of non-starch polysaccharides in cecal digesta. In rats fed 80 g/kg A. pycnantha gum, 3.44 g of soluble non-starch polysaccharides was measured in the ceca, which was 58% of the dry weight of the cecal contents. We conclude that the biological activities of the Australian Acacia gums were similar to those of gum arabic and that these gums may have potential value as human food ingredients.

JABUTICABA FRUIT BEER: PHYSICOCHEMICAL AND SENSORY EVALUATION

This research focused on craft beer production of jabuticaba (Myrciaria cauliflora Berg) “fruit beer” and the physicochemical and sensory analisys of the samples. The research was divided into four treatments regarding the stage of fruit addition during the brewing process (Boiling, Fermentation, Maturation) and the Control (all malt), with three replicates each. The mashing was performed by the infusion method, and the wort was boiled for 60 minutes. The fermentation took place at 10 °C ± 1, and the green beer was later bottled with priming sugar and bottle conditioned for carbonation. The maturation occurred in the bottles for 30 days at 0 °C ± 1, except for the Maturation treatment. The beers were analyzed physicochemically for the parameters of alcoholic content, real extract, apparent extract, apparent fermentability, true fermentability, color, bitterness, turbidity, pH, total acidity and carbon dioxide. The beers were submitted to sensory analysis by affective test using 9-point hedonic scale. The addition of jabuticaba increases the total acidity, CO2 content and bitterness of the beer, but does not alter its real extract, apparent extract and pH. Sensorially, treatments and Control had the same preference for all parameters analyzed (appearance, aroma, flavor and overall evaluation).

261 Increasing dietary amylose reduces rate of starch digestion and increases microbial fermentation in weaned pigs

Abstract Beneficial effects of SCFA in modulating gut health stimulated interest on dietary strategies to increase intestinal microbial activity and digesta SCFA. Amylose has lower apparent ileal digestibility (AID) than amylopectin. In the large intestine, undigested starch is fermented by microbes producing SCFA. The objective was to determine effects of increasing dietary amylose on starch flow and metabolite profile along the intestinal tract in weaned pigs. Weaned pigs (n=32; initial BW, 8.4 kg) were randomly allocated to 4 diets containing 67% starch with 0, 20, 35, or 70% amylose in a randomized complete block design. On day 21, pigs were euthanized to collect digesta and feces for evaluating starch digestion and metabolite profiles. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility minus AID. Feed intake was 12% lower (P < 0.05) and growth rate was 18% lower (P < 0.05) for pigs fed 70% amylose than pigs fed 0, 20, or 35% amylose. Feed efficiency was greatest (P < 0.05) for pigs fed with 35% amylose. The AID of starch was 44% lower (P < 0.05) in pigs fed 70% amylose. Starch was completely digested by the proximal colon in pigs fed 0, 20, or 35% amylose, but AHF of starch was 14% greater (P < 0.05) in pigs fed 70% amylose. Increasing dietary amylose did not alter digesta SCFA in the small intestine, but increased (P < 0.05) digesta SCFA in the cecum, specifically acetate and total SCFA, and increased (P < 0.05) propionate and valerate in all sections of the colon. In conclusion, increasing dietary amylose in weaned pigs stimulated hindgut fermentation of starch with a corresponding increase in digesta total SCFA in the cecum and colon. Optimizing dietary amylose may exert its effect as dietary prebiotic while promoting an optimal growth rate in young pigs.

Enhanced reductive de-chlorination of a solvent contaminated aquifer through addition and apparent fermentation of cyclodextrin

In a field study, aqueous cyclodextrin (CD) was investigated for its ability to extract chlorinated volatile organic compounds (cVOC), such as trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), and dichloroethene (DCE) through in-situ flushing of a sandy aquifer. After cessation of aquifer flushing, a plume of CD was left. Changes in CD, cVOC, and inorganic terminal electron acceptors (TEAs) (DO, nitrate, sulfate, iron) were monitored in four rounds of wellwater sampling (20, 210, 342, and 425days after cessation of active pumping). Post-CD flushing VOC levels rebounded (850% for TCE, 190% for TCA, and 53% for DCE) between the first two sampling rounds, apparently due to rate-limited desorption from aquifer media and dissolution from remaining NAPL. However, substantial reduction in the mass of TCE (6.3 to 0.11mol: 98%) and TCA (2.8 to 0.73mol: 74%) in groundwater was observed between 210 and 425days. DCE should primarily be produced from the degradation of TCE and is expected to subsequently degrade to chloroethene. Since DCE levels decreased only slightly (0.23 to 0.17mol: 26%), its degradation rate should be similar to that produced from the decaying TCE. Cyclodextrin was monitored starting from day 210. The mass of residual CD (as measured by Total Organic Carbon) decreased from 150mol (day 210) to 66 (day 425) (56% decrease). The naturally anaerobic zone within the aquifer where residual CD mass decreased coincided with a loss of other major potential TEAs: nitrate (97% loss), sulfate (31%) and iron (31%). In other studies, TCE and 1,1,1-TCA have been found to be more energetically favorable TEAs than sulfate and iron and their degradation via reductive dechlorination has been found to be enhanced by the fermentation of carbohydrates. Such processes can explain these observations, but more investigation is needed to evaluate whether residual levels of CD can facilitate the anaerobic degradation of chlorinated VOCs.

Performance of lactating dairy cows fed a diet based on treated rice straw and supplemented with pelleted sweet potato vines

The purpose of this study was to evaluate the effects of sweet potato vine pellet (SWEPP) in concentrate diets on nutrient digestibility and rumen ecology in lactating dairy cows fed on urea-treated rice straw. Three multiparous Holstein crossbred cows in mid-lactation were randomly assigned according to a 3 × 3 Latin square design, and the treatments were as follows: T1 = control (no supplementation), T2 = supplementation of sweet potato vine pellet with 50 g/kg urea (SWEPP I) at 300 g/head/day, and T3 = supplementation of sweet potato pellet with 100 g/kg urea (SWEPP II) at 300 g/head/day, in concentrate diets, respectively. The result revealed that supplementation of SWEPP did not affect feed intake, ruminal pH, and blood urea nitrogen (P > 0.05). However, apparent digestibilities of organic matter, crude protein, and neutral detergent fiber were higher in SWEPP II than those in others. Furthermore, ruminal ammonia nitrogen (NH(3)-N) and milk yield were significantly higher (P < 0.05) in animals fed with SWEPP II than those fed with SWEPP I and control, respectively. In addition, there were no differences in purine derivatives and microbial nitrogen supply among all the treatments. Based on this study, it could be concluded that SWEPP is a good source of supplement which resulted in significant improvement in apparent digestibility, rumen fermentation, and milk yield in lactating dairy cows fed on urea-treated rice straw.

Kilning Conditions for the Optimization of Enzyme Levels in Buckwheat

Buckwheat is a novel ingredient in malting and brewing, and therefore, requires optimization of the malting and brewing processes. In this study, three temperature regimens, 48 hr at 40°C (KR1), 5 hr at 40°C + 11 hr at 50°C (KR2), and 5 hr at 40°C + 3 hr at 50°C + 3 hr at 60°C (KR3) were used to kiln green buckwheat malt produced from grains steeped for 12 hr at 10°C and germinated for 96 hr at 15°C. Kilning regimens KR1, KR2, and KR3 produced malts with a moisture content of 6.8, 6.2, and 5.7%, respectively. Although an increased enzymatic activity level in buckwheat malt was noted with increased thermal exposure during the kilning regimen, it is not reflected in its brewing characteristics with regard to extract and apparent fermentability after using an optimized mashing system. However, the effect of treatment at higher temperatures with respect to enzymatic activity levels in buckwheat malt is reflected by rapid visco analysis where decreased peak viscosities correlate to an increased amylolytic activity level. The results of this study suggest that buckwheat, kilned using KR3, which was found to contain highest levels of amylolytic enzymes and produced the highest levels of total soluble nitrogen and free amino nitrogen when optimally mashed, be recommended for the kilning regimen of buckwheat green malt.

The Influence of Starter Cultures on Barley Contaminated with Fusarium Culmorum TMW 4.0754

This study investigates the effects of lactic acid bacteria (LAB) added concomitantly to barley infected with fungal spores or mycelia of Fusarium culmorum TMW 4.0754. The trials were performed in a micromalting plant simulating an industrial malting program. Malt samples were compared with those of nonacidified barley, disinfected nonacidified barley, chemically acidified barley, and barley with additional modified DeMan-Rogosa-Sharpe 4 medium. All control samples had fungal spores and fungal mycelia added. Bacterial cultures were chosen as a result of their enzymatic (proteolytic/amylolytic) activity level or their good acidification properties. The effects of the LAB and Fusarium-infected malts on wort characteristics were investigated. Characteristics such as pH, extract, color, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, and lautering performance of the resultant worts were determined. Results showed that spores of F. culmorum TMW 4.0754 do not affect the quality of malt or wort. The quality of wort was reduced when mycelia of F. culmorum were applied in the presence of LAB or chemical lactic acid leading to slower filtration rates, lower extract, fermentability, TSN, and FAN yields along with higher viscosity levels. These effects seemed to depend mainly on the presence of mycelia together with the content of lactic acid present.

Biological Acidification of a Mash Containing 20% Barley Using Lactobacillus Amylovorus FST 1.1: Its Effects on Wort and Beer Quality

This study evaluates the influence of biological mash and wort acidification using a thermophilic proteolytic/amylolytic active Lactobacillus amylovorus on brews containing 20% (wt/wt) unmalted barley in laboratory-scale trials as well as 10-hL pilot-scale brews. The biologically acidified mash was compared with a chemically acidified mash, 100% malt mash unacidified, and 80% malt (wt/wt)/20% (wt/wt) barley unacidified mash. Characteristics such as pH, extract, color, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, β-glucan, sugar, and amino acid profiles of the resultant worts were determined. In the pilot-scale brews, foam stability, accelerated shelf life, and sensory evaluation of the beer was determined. It was clearly shown that biological acidification (BA) could compensate for a lower enzymatic activity level of grists containing 20% (wt/wt) barley. Increased levels of extract, fermentability, TSN, and FAN were observed in the laboratory-mash trials along with a sharp decrease in β-glucan levels when BA was applied. Cast-out wort showed a considerable increase in nitrogenous fractions. Viscosity was decreased by acidification of mashes but did not correlate with β-glucan levels. The final biologically acidified beer showed a lighter color, improved foam stability, and a more well-rounded taste with increased shelf life in comparison with the chemically and the nonacidified beer.

The Influence of Lactic Acid Bacteria on the Quality of Malt

In this study three strains of lactic acid bacteria were applied during the malting process to evaluate the impact on malt and wort quality. The trials were performed in a micromalting plant simulating an industrial malting programme. The samples were compared to chemically acidified as well as non-acidified malt. Bacterial cultures were chosen with reference to their enzymatic (proteolytic/amylolytic) activity, or their good acidifying properties. The effects of lactic acid bacteria on wort characteristics were investigated and compared to wort produced from 100% unacidified malt. A chemical food grade lactic acid was also used to acidify the barley for comparison purposes. Characteristics such as pH, extract, colour, viscosity, total soluble nitrogen, free amino nitrogen, apparent fermentability, β-glucan and lautering performance of the resultant worts were determined. Results showed improved levels of β-glucanase in the malt although reduced malt friability was observed where LAB was employed. An improved lautering performance, lower wort viscosity and elevated TSN levels were also reported where LAB exhibiting protease activity were applied.

The Effect of Germination Temperature on Malt Quality of Buckwheat

Common buckwheat (Fagopyrum esculentum) with and without hull was malted at four germination temperatures, 9.5, 14.9, 16.5, and 20.2°C. Optimum characteristics of malts and resulting worts were obtained when buckwheat was germinated at 16.5 and 20.2°C. Buckwheat without hull germinated at these temperatures showed similar values in soluble nitrogen and free amino nitrogen to barley malt. Both α- and β-amylase activity levels were low in malted buckwheat. The maximum activity level of α-amylase was 47.79 units g−1 (wet wt) in buckwheat without hull and germinated at 16.5°C. The maximum activity level of β-amylase was induced in buckwheat germinated at 20.2°C: 129.80 and 125.68 units g−1 (wet wt) were found in buckwheat with and buckwheat without hull, respectively. Maximum apparent fermentability (56%) was reached when buckwheat was germinated at a temperature of 20.2°C. Although amylolytic activity and fermentability levels were low in malted buckwheat, buckwheat malt appears to have potential as a brewing ingredient once malting and mashing conditions are optimized.

Effects of cereal grain supplementation on apparent digestibility of nutrients and concentrations of fermentation end-products in the feces and serum of horses consuming alfalfa cubes.

Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carbohydrates (TNC). Due to acute laminitis, three geldings (one in the control group and two in the barley group) were excluded. Because of this and multiple incidents of gas colic, TNC level was decreased to 0.2% of BW to ensure the geldings' health throughout the adaptation (7 d) and sample collection (5 d) periods. Grain intakes varied (P < 0.05) and reflected the different TNC concentrations. Apparent digestibilities of DM, OM, CP, NDF, ADF, and cellulose were not affected (P > 0.05) by grain supplementation and averaged 63.2, 63.1, 79.5, 42.7, 39.9, and 50.3%, respectively. Regardless of the source, grain supplementation increased (P < 0.05) apparent digestibility of TNC (from 85.6 to 94.6%) and decreased (P < 0.05) fecal pH (from 7.04 to 6.74). Fecal concentrations of total VFA (mg/g of DM) were greatest for the barley and naked oats diets (averaging 11.73), intermediate for the oats diet (8.00), and least for the control and corn diets (averaging 5.00; P < 0.05). Fecal concentrations of lactate (microg/g of DM) were greatest for the barley diet (254), intermediate for the oats diet (138), and least for the remaining diets (averaging 100; P < 0.05). Fecal concentrations of NH3 N (mg/g of DM) were greatest for the naked oats diet (1.68), intermediate for the barley and oats diets (averaging 0.86), and least for the remaining diets (averaging 0.63; P < 0.05). Serum concentration of lactate was 46% higher (P < 0.05) for the control than for the grain diets (averaging 0.05 mg/100 mL). Feeding barley, corn, naked oats, and oats contributed to 13, 15, 8, and 20% higher (P < 0.05) serum NH3 N concentrations than the control diet (0.25 mg/100 mL). Higher (P < 0.05) serum concentrations of urea N (mg/100 mL) were detected for the control, barley, and naked oats diets (averaging 25.28) than for the corn or oats diets (averaging 22.21). Results suggest that horses consuming alfalfa cubes could be supplemented with rolled barley, corn, naked oats, or oats at levels not exceeding 0.2% of BW as TNC without affecting nutrient digestion or overall health negatively.

Application of Biological Acidification to Improve the Quality and Processability of Wort Produced from 50% Raw Barley

In this study four strains of lactic acid bacteria (LAB) were chosen to bioacidify a mash containing 50% barley and 50% malt. The strains were isolated from malted and unmalted barley and assayed for extracellular enzymatic activities (proteases, amylases, β-glucanases). The biologically acidified mash was compared to a chemically acidified mash, 100% malt mash un-acidified and 50% malt and 50% barley mash unacidified. Characteristics such as pH, extract, colour, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, β-glucan and lautering performance of the resultant worts were determined. A model lautering system replicating one used in a brewery was designed and built in University College Cork (UCC) to measure the lautering performance of the bioacidified mashes. The new system was compared to the filtration method used in EBC method 4.5.1. Overall the addition of LAB to bioacidify a mash of 50% barley and 50% malt resulted in faster filtration times, which correlated with decreased β-glucan levels. Proteolytic LAB had a positive influence on the quality of wort and resulted in increased FAN levels. Lighter colour worts were observed along with increased extract levels.

Use of some novel alternative electron sinks to inhibit ruminal methanogenesis.

Several compounds were evaluated in vitro as alternative electron sinks to ruminal methanogenesis. They were incubated with ruminal fluid, buffer mixture, and finely ground alfalfa hay for 24 h, at 0, 6, 12, and 18 mM initial concentrations. The propionate enhancer oxaloacetic acid, the butyrate enhancer beta-hydroxybutyrate, and the butyrate unsaturated analog 3-butenoic acid were ineffective in decreasing methanogenesis. Nevertheless, beta-hydroxybutyrate increased apparent fermentation of the alfalfa hay substrate from 58.0 to 63.4%, and 3-butenoic acid seemed to increase it from 62.0 to 73.7%. Almost all of added oxaloacetic acid disappeared during the incubation, while only between 30.3 and 53.4% of beta-hydroxybutyrate disappeared. The butyrate enhancers acetoacetate and crotonic acid, and the butyrate unsaturated analog 2-butynoic acid, decreased methanogenesis by a maximum of 18,9 and 9%, respectively. Crotonic acid at 18 mM initial concentration seemed to increase the substrate apparent fermentation from 57.0 to 68.2%. Between 78.6 and 100% of acetoacetate disappeared during the incubation. The propionate unsaturated analog propynoic acid, and the unsaturated ester ethyl 2-butynoate, decreased methanogenesis by a maximum of 76 and 79%, respectively. Less than 5% of propynoic acid disappeared. The substrate apparent fermentation was decreased by propynoic acid from 62.0 to 57.4%, and seemed to have been decreased by ethyl 2-butynoate from 62.0 to 29.3%. More accurate measurements of the disappearance of some of the compounds studied are needed to better understand how they are metabolized and how they affect fermentation.

Effect of transgalactooligosaccharides on the composition of the human intestinal microflora and on putative risk markers for colon cancer

Nondigestible oligosaccharides have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and by decreasing the toxicity of the colon contents. We compared the effect of 2 doses of transgalactooligosaccharides and a placebo on the composition and activity of the intestinal microflora in 18 women and 22 men. Strictly controlled experimental diets were supplied to 3 intervention groups in a parallel design. The study was divided into 2 consecutive 3-wk periods during which each participant consumed a run-in diet followed by an intervention diet that differed only in the amount of transgalactooligosaccharides: 0 (placebo), 7.5, and 15 g/d. Breath samples and fecal samples were collected at the end of both the run-in and intervention periods. Apparent fermentability of transgalactooligosaccharides was 100%. The highest dose of transgalactooligosaccharides significantly increased the concentration of breath hydrogen by 130% (P < 0.01) and the nitrogen density of the feces by 8.5% (P < 0.05). The number of bifidobacteria increased after both placebo and transgalactooligosaccharides ingestion, but the differences between these increases were not significantly different. Transgalactooligosaccharides did not significantly affect bowel habits; stool composition; the concentration of short-chain fatty acids or bile acids in fecal water; the concentration of ammonia, indoles, or skatoles in feces; fecal pH; or the composition of the intestinal microflora. We conclude that transgalactooligosaccharides are completely fermented in the human colon, but do not beneficially change the composition of the intestinal microflora, the amount of protein fermentation products in feces, or the profile of bile acids in fecal water.

Determination of Fermentability (Final Attenuation) of Wort

Two methods for the determination of the apparent fermentability (attenuation limit) of wort, the regular fermentation as a reference method as well as a more rapid method have been collaboratively tested by members of the Analysis Committee of the European Brewery Convention to obtain repeatability (r95)and reproducibility (R95) values and to form an idea of the equivalence of these two procedures based on the comparison of results obtained from identical samples. In the collaborative trials the 14th EBC Standard Malt and two industrial worts were analysed. Repeatability (r95) and reproducibility (R95) values of 0.5% and 2.9% respectively at a mean level of 83.9% were obtained for laboratory wort from malt using the reference fermentation method. Using the rapid fermentation method the values were 0.9% and 2.4% respectively at the mean level of 82.8%. The precision values for industrial wort using the reference fermentation method were r95 = 0.4% and R95 = 2.4% for mean levels of 81.3 and 82.4%, using the rapid method 0.3% and 3.5% were obtained respectively for mean levels of 80.5 and 81.7%. The reference fermentation is more precise in terms of reproducibility and yields higher results. The rapid method is recommended for guideline purposes only.

Bacterial fermentation of fructooligosaccharides and resistant starch in patients with an ileal pouch-anal anastomosis

Patients with large bowel disease may undergo ileal pouch-anal anastomosis, in which the colon is removed and part of the distal ileum is used to construct a pelvic reservoir. Competence of the ileal pouch to ferment carbohydrates is associated with the absence of pouchitis. However, the extent to which bacterial fermentation takes place and whether it is affected by diet are unclear. We investigated fermentation of two nondigestible carbohydrates, fructooligosaccharides and resistant starch, in 15 healthy patients with an ileal pouch by using a placebo-controlled crossover design (with glucose as the placebo). Apparent fermentability of fructooligosaccharides was 83%; that of resistant starch was 46%. Resistant starch increased fecal excretion of butyrate by 69% whereas fructooligosaccharides reduced excretion of amino acid-derived isobutyrate by 94% and of isovalerate by 77%. Fructooligosaccharides also significantly increased fecal weight (651 compared with 541 g/d) and breath-hydrogen excretion (286 compared with 85 ppm x h). Bacterial fermentation of nondigestible carbohydrates in pouches takes place to an appreciable extent and in a substrate-specific manner. The relation between such fermentation and inflammation of the pouch (pouchitis) deserves study.

Ruminal nitrogen metabolism in calves and sheep. 3. Effect of hay-concentrate ratio in calves

During the milk feeding period (ca. 55th day of life) and 2 weeks after the milk feeding period (ca. 80th day of life) the influence of a hay quota in the ration (on DM basis) of 6, 10, 14 and 18% in the milk feeding period and of 16, 23, 31 and 37% in the period after milk feeding was tested as to ruminal N metabolization with calves supplied with duodenal re-entrant cannulae. The increase of the hay quota in the ration for ruminating calves reduced as a tendency duodenal NAN passage, its bacterial N-quota, post-ruminal NAN digestibility and, due to a worse utilization of available N for bacterial N-synthesis, bacterial N-synthesis rate. The apparent fermentation of organic matter was, as a tendency, increased with the growing hay quota in the ration.

Metabolism and physiological behaviour of Leuconostoc mesenteroides subsp. mesenteroides growing on raffinose

AbstractThe α‐galactosidase activities of 11 strains of Leuconostoc mesenteroides subsp. mesenteroides grown on glucose, lactose or raffinose were determined. The inductive effects of lactose and raffinose differed depending on the strain. In four of the strains, α‐galactosidase activity of cells grown on lactose was higher than that of cells grown on raffinose, while the reverse was true for one other strain. The study of two strains exhibiting a different behaviour was extended to all raffinose‐component sugars: melibiose, sucrose, glucose, galactose and fructose. The apparent fermentation yields with raffinose‐component sugars complied with heterofermentation theory, except for sucrose, where there was a 40% deficit in fermentation products. Raffinose hydrolysis enzymes (α‐galactosidase and β‐fructosidase) underwent a catabolic repression by glucose. Growth on raffinose was considerably stimulated if the inoculum was first grown on melibiose or raffinose (induction of α‐galactosidase).

Untersuchungen zum ruminalen Stickstoffumsatz bei Kälbern und Schafen

In a model experiment with calves supplied with duodenal re-entrant and rumen fistula resp. rations were tested that were energetically different (535 and 585 EFU cattle/kg DM) due to changing quotas of wheat starch and straw resp., dry matter intake being equal, and in which 45% of the crude protein came from soybean oil meal or urea resp. Due to the N-equivalent exchange of soybean oil meal by urea in rations for ruminating calves (130th day of life) the ammonia-N content in the rumen fluid, the quota of bacteria-N in the duodenal non-ammonia N (NAN) as well as the fermentation of crude plant protein in the ration were clearly increased. The iso-acid content in the rumen fluid and the utilization of the N available for bacteria N synthesis (N intake minus not degraded feed N in the duodenum) were reduced. An influence on duodenal NAN passage, on the apparent fermentation of the organic matter, on postruminal NAN digestibility and on the content of amino acid nitrogen as well as the amino acid composition of duodenal NAN could not be proved. A ca. 20% higher energy intake by ruminating calves did not have a clear influence on other parameters, with the exception of the reduction of the molar quota of acetic acid in favour of the quota of propionic acid in the rumen fluid.