43010269
Effect of Yucca schidigera on ruminal fermentation and nutrient digestion in heifers.
In a replicated 3 x 3 Latin square experiment, six heifers (443 +/- 6.1 kg) fed a 61% barley grain:39% alfalfa silage diet (DM basis) were given intraruminal doses of powdered Yucca schidigera (YS). Doses of 0 (control), 20, or 60 g/d were given at 0800 daily. Ruminal content was sampled 0, 2, 4, and 6 h after dosing. Acidity, concentrations of reducing sugars, free amino acids, and peptides in the rumen were not affected (P > .05) by YS. Relative to control, ruminal ammonia concentration was reduced (P < .05) 2 h after YS dosing. Ruminal propionate concentration was increased (P < .05) by YS. Protozoal numbers in the rumen were lower (P < .05) with YS than without. Yucca did not affect (P > .05) rate or extent of in situ DM degradability. Fibrolytic, amylolytic, and proteolytic activities in ruminal contents were similar among treatments (P > .05). Dry matter intake, apparent digestibilities of DM, NDF, and CP, nitrogen balance, and microbial protein synthesis in the rumen were not affected (P > .05) by treatment. The effect of YS on ruminal ammonia concentration likely resulted from a decreased concentration of protozoa and, presumably, from ammonia binding by YS. The effect on ruminal propionate was probably a result of a selective inhibitory effect of YS on rumen microbial species.
86635851
Effect of dietary Yucca schidigera extract on rumen and blood profiles of steers fed concentrate- or roughage-based diets
In two experiments, four rumen-fistulated steers were used in a Latin square design arrangement with each rotation period of 15 days. Yucca schidigera extract (YE) was added at the rate of 250 mg kg−1 of mixed feed. In the first experiment, four isonitrogenous high-roughage (HR) feeds were tested: HR + soybean meal (R1); R1 + YE (R2); HR + urea (R3); R3 + YE (R4). Feed intakes (FI) (kg day−1) were 11.4, 11.2, 11.3, and 11.0 for R1, R2, R3 and R4, respectively. Ruminal pH and rumen ammonia-N (RAN, mg dl−1) for R1, R2, R3 and R4 (pooled values for 0, 3, 6, 9 h postfeeding, HPF) were: 6.5, 11.5; 6.6, 10.2; 6.6, 15.1; 6.6, 12.9. Plasma ammonia-N (μg ml−1) and plasma urea-N (mg dl−1) for R1, R2, R3 and R4, respectively, were: 1.13, 13.64; 1.24, 14.79; 1.19, 16.11; and 1.04, 14.7 In Trial 2, the four isonitrogenous, high-concentrate (HC) diets were: HC (barley) + soybean meal (C1); C1 + YE (C2); HC + urea (C3); C3 + YE (C4). Average daily FI (kg) were: 14.2, 13.5, 14.2 and 13.7 for C1, C2, C3 and C4, respectively. Ruminal pH and RAN for C1, C2, C3 and C4, respectively, were: 5.81, 7.92; 5.82, 6.88; 6.09, 10.85; 6.00, 10.50 The plasma ammonia-N (PAN) and plasma urea-N (PUN) for C1, C2, C3 and C4 were: 1.17, 14.00; 0.89, 11.52; 1.15, 13.87; 1.15, 13.76. In the HR trial, rumen fluid concentrations of different volatile fatty acids (VFA) (averaged across time) were not different among treatments, except that isovalerate concentration in R1 was higher (P < 0.05) than R2. Numerically, acetate concentration was lower in R2 vs. R1, and propionate, isobutyrate and valerate concentrations were higher in R4 vs. R3. There was less fluctuation in VFA concentrations at different HPF in R4 vs. R3. Total VFA concentration was higher in R1 vs. R2 and R4 vs. R3. The acetate:propionate ratio was lower in R1 vs. R2 and R4 vs. R3. In the HC trial, acetate, propionate, isobutyrate and valerate concentrations were lower in the YE diets. Total VFA concentrations and acetate:propionate ratios were generally lower in the YE diets. The results showed a tendency for YE to reduce RAN, PAN and PUN, which could lead to more efficient utilization of dietary nitrogen, particularly when HR diets supplemented with urea are fed.
1652821
Effect of steroidal sapogenins on ruminal fermentation and on production of lactating dairy cows.
Supplementation of dairy rations with steroidal sapogenins was evaluated in an in vitro, an in situ, and a production trial. Sixteen in vitro semicontinuous rumen cultures were supplied a 55:45 concentrate to roughage substrate with Sarsaponin concentrations of 0, 33, 55, and 77 ppm of air-dry feed for 22 d. Supplementation decreased protozoa numbers and increased bacterial numbers and acid detergent fiber digestion. Digestion of feed nitrogen tended to be lowest at the highest concentration of Sarsaponin, whereas microbial nitrogen output was similar for all concentrations. In rumen-cannulated animals fed a typical dairy ration, in situ rate of disappearance of organic matter, acid detergent fiber, and nitrogen of a complete ration substrate tended to be lower with 77 ppm added Sarsaponin. In a production trial, 16 primiparous dairy cows 6 to 10 wk postpartum were fed rations containing either 0 or 77 ppm Sarsaponin. Sarsaponin did not alter dry matter intake, digestibility, body weight change, or milk production and composition. Supplementation had no significant effect on ruminal fermentation in vivo as reflected by concentrations of ruminal ammonia nitrogen, blood urea, or molar ratios and concentrations of ruminal volatile fatty acids.
34549966
Effects of sarsaponin on digestion and passage rates in cattle fed medium to low concentrate.
Four dairy cows with duodenal cannulae were fed diets consisting of sorghum silage (67% of dietary dry matter) at 85% of ad libitum intake with 0 (control diet) or 44 ppm (dry matter) sarsaponin (sarsaponin diet) in a crossover experiment. Digestion coefficients for organic matter were low but increased by addition of sarsaponin both in the rumen (43.7 versus 32.4%) and total tract (52.1 versus 48.2%). Digestibilities of starch and nitrogen in the rumen and total tract and passage rates of fluid, concentrate, and silage tended to be greater for the sarsaponin diet. Extent of ruminal digestion of organic matter was related to passage rate of concentrate (correlation .81) and fluid (correlation .75). In a second study, diets contained 50% concentrate either with or without sarsaponin added at 44 ppm. Ruminal pH for animals given sarsaponin tended to be lower 4, 8, and 12 h after feeding. In situ rate constants of dry matter disappearance tended to be greater with the control diet for corn, alfalfa, and prairie hay and lower for milo and soybean meal. Lag time of digestion tended to be longer with the sarsaponin diet for corn, milo, soybean meal, and corn gluten meal but shorter for alfalfa and prairie hay. Although sarsaponin may increase ruminal digestion of medium to low concentrate diets, in situ data indicate that effects may differ with type of feed.
29951325
Influence of yucca extract on ruminal metabolism in cows.
Two trials were conducted to determine the influence of yucca extract on ruminal digestion, fermentation, and ammonia patterns using ruminally and duodenally cannulated dairy cows. In Trial 1, urea at 0 or 1% of the diet and yucca extract at 0 or 4 g/d formed four dietary treatments in a 2 x 2 factorial arrangement. The experimental design was a 4 x 4 Latin square with 15-d periods. Duodenal digesta were sampled every 6 h during the last 4 d of each period to determine OM and ADF digestibilities and bacterial protein synthesis in the rumen using Cr2O3 and 15N markers. Ruminal digestibilities were (percentage): OM 46.3 vs 43.0%, and ADF 35.9 vs 41.4%, with or without Deodorase. Microbial protein entering the duodenum averaged 2.7 vs 3.1 kg/d for the respective treatments. Ruminal measurements were not affected by treatment (P > .10). In Trial 2, five cows were used in a 5 x 5 Latin square with 7-d periods. Treatments were 0, 2, 4, 6, and 8 g/d of yucca extract administered via ruminal cannulas. Ruminal fluid was sampled 0, 1, 2, 4, 7, 11, 16, and 22 h after feeding during the last 2 d of each period. Average ruminal NH3 N ranged from 31.4 to 35.4 mg/dL, pH 5.99 to 6.18, and total VFA from 120 to 129 mM, and all did not differ among treatments (P > .10). Yucca extract administered at 4 g/d did not significantly affect ruminal digestibilities of OM and ADF, and up to 8 g/d did not affect ruminal NH3, pH, or VFA.
37319343
Influence of Yucca shidigera extract on ruminal ammonia concentrations and ruminal microorganisms
An extract of the desert plant Yucca shidigera was assessed for its possible benefit in ruminal fermentation. The extract bound ammonia in aqueous solution when concentrations of ammonia were low (up to 0.4 mM) and when the extract was added at a high concentration to the sample (20%, vol/vol). The apparent ammonia-binding capability was retained after autoclaving and was decreased slightly following dialysis. Acid-precipitated extract was inactive. No evidence of substantial ammonia binding was found at higher ammonia concentrations (up to 30 mM). When Y. shidigera extract (1%, vol/vol) was added to strained rumen fluid in vitro, a small (6%) but significant (P < 0.05) decrease in ammonia concentration occurred, apparently because of decreased proteolysis. Inclusion of Y. shidigera extract (1%, vol/vol) in the growth medium of the rumen bacterium Streptococcus bovis ES1 extended its lag phase, while growth of Butyrivibrio fibrisolvens SH13 was abolished. The growth of Prevotella (Bacteroides) ruminicola B(1)4 was stimulated, and that of Selenomonas ruminantium Z108 was unaffected. Protozoal activity, as measured by the breakdown of 14C-leucine-labelled S. ruminantium in rumen fluid incubated in vitro, was abolished by the addition of 1% extract. The antimicrobial activities were unaffected by precipitating tannins with polyvinylpyrrolidone, but a butanol extract, containing the saponin fraction, retained its antibacterial and antiprotozoal effects. Saponins from other sources were less effective against protozoa than Y. shidigera saponins. Y. shidigera extract, therefore, appears unlikely to influence ammonia concentration in the rumen directly, but its saponins have antimicrobial properties, particularly in suppressing ciliate protozoa, which may prove beneficial to ruminal fermentation and may lead indirectly to lower ruminal ammonia concentrations.
44421032
The Rumen Protozoa
In addition to the bacteria in the rumen there are many larger (5–250/mm long) organisms which at various times have been designated protozoa. Of these the ‘ovals’ (Quin’s and Eadie’s) are now known to be large bacteria (Orpin, 1976) and the ‘flagellates’ Neocallimastix frontalis, Piromonas communis and Sphaeromonas communis are the zoospores of phycomycete fungi (Orpin, 1977a, b). There are genuine flagellates in the rumen, e.g. Trichomonas spp., Monoceromonas sp. and Chilomastix sp., but almost nothing is known about their metabolism (Jensen and Hammon, 1964). The largest, most obvious and most important protozoa are the ciliates, of which there are two groups both in the subclass Trichostomatia. The so called ‘holotrich’ protozoa belong to the order Vestibuliferida and the entodiniomorphs to the order Entodiniomorphida, suborder Entodiniomorphina and family Ophryoscolecidae. As the properties and metabolism of these two protozoal groups are different, they will be considered separately below.
85987435
Effects of Yucca schidigera extract on fermentation and degradation of steroidal saponins in the rumen simulation technique (RUSITEC)
Abstract A rumen simulation technique (RUSITEC) apparatus with eight 940 ml fermentation vessels was used to study the effects of the steroidal saponins in Yucca schidigera extract (YE) on ruminal microbial activity and saponin degradation. The YE contained approximately 4.4% (w/w) saponin, as smilagenin equivalents, and was included at 0 (control) or 0.5 mg ml −1 ( n =4) in the McDougall's buffer infused continuously into the vessels (dilution rate=0.75 day −1 ). Each vessel received 5 g chopped alfalfa hay and 5 g concentrate (as-fed basis) daily for 22 days. Ammonia concentrations were lower ( P P >0.05) by YE, but molar proportions of iso-butyric and iso-valeric acids were lower ( P −1 did not affect ( P >0.05) dry matter disappearance (DMD) from hay or from concentrate, nor did it affect total gas or methane production, or bacterial numbers (total or cellulolytic populations) in homogenates prepared from fermenter vessel liquid and feed particles. Protozoal numbers in the homogenates were substantially reduced ( P −1 ), protease activity was increased ( P 2 were unaffected ( P >0.05) and activity against Ala 5 was reduced by 25% ( P >0.05). When the homogenates from control and YE-supplemented (0.5 mg ml −1 ) vessels were used to inoculate roll tubes containing 0 or 5 mg ml −1 of YE, fewer colonies developed ( P −1 altered proteolytic activity and reduced protozoal numbers, but did not affect DMD or bacterial activity, and did not induce resistance to YE at a concentration of 5 mg ml −1 .
3976812
Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition.
There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. The original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306; Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Triethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and beta-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch, their fermentations are like that of cellulose but faster and yield no lactic acid. Physical and biological properties of carbohydrate fractions are more important than their intrinsic composition.
84215471
Effect of formaldehyde-treated barley or escape protein on the ruminal environment and digestion in steers
Six Holstein steers fitted with ruminal and duodenal cannulae were fed three diets: formaldehyde-treated rolled barley (0.11% wt wt−1) with canola meal (FTB); untreated rolled barley supplemented with corn distillers' grain and fishmeal (EPB); and untreated rolled barley with canola meal (CON). Foam production from ruminal fluid did not differ among diets. Mean viscosity of ruminal fluid from steers fed FTB was lower (P < 0.02) than rumen fluid from steers fed CON. Ruminal fluid pH of steers fed FTB was lower 2 h after feeding than in steers fed the EPB or CON diets. FTB led to lower (P < 0.02) ruminal ammonia concentrations 1 and 2 h after feeding and lower (P < 0.1) plasma urea nitrogen concentrations 4 h after feeding compared to EPB or CON diets. FTB and EPB tended to lower the ruminal concentration of volatile fatty acids (VFA) associated with microbial amino acid metabolism. Intake, ruminal and postruminal digestion of DM, OM, starch and NDF were not influenced by diet. While EPB had no effect on to...
20377363
Automated simultaneous determination of ammonia and total amino acids in ruminal fluid and in vitro media.
Catalyzed phenol-hypochlorite and ninhydrin colorimetric procedures were adapted to the Technicon AutoAnalyzer for simultaneous determination of ammonia and total amino acids in ruminal fluid or ruminal in vitro media. The manifold developed was compatible with a sampling rate of 40/h without significant sample-to-sample carryover. With proper storage, reagents for both the phenol-hypochlorite and the air-stable ninhydrin systems were stable for 8 mo or more. Response of individual amino acids in the phenol-hypochlorite system were generally 1% or less than equimolar amounts of ammonia. Certain amino acids inhibited ammonia color yield 10 to 15% when with equimolar amounts of ammonia; however, the inhibitory effect of casein amino acids was only 2 to 3%. Although ninhydrin response, relative to leucine, of individual alpha-amino acids ranged from 62 (valine) to 151% (histidine), recoveries of casein amino acids from ruminal fluid had coefficients of variation of 1% or less. Coefficients of variation for ammonia recoveries from ruminal fluid by the phenol-hypochlorite procedure were about half of those for the Conway microdiffusion technique. Intraclass correlations for the adapted procedures indicated high degrees of accuracy and precision for both ammonia and amino acid analyses.
85156893
Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents
Three procedures for extracting polysaccharide-degrading enzymes (PDE) from ruminal contents were compared, and the effects of diet, inoculum preparation and freezing of samples on recovery of enzyme activities were evaluated. Four nonlactating cows and four heifers were fed either high-forage (83%, dry matter [DM] basis) or high-grain (91%, DM basis) diets. Three sample types, (1) enriched ruminal fluid; (2) blended enriched ruminal fluid; and (3) whole ruminal content, were analyzed fresh or after having been frozen (−40 °C) for 48 h. Four cell-free preparations of each sample type were assayed: (1) control (no enzyme extraction); and enzymes extracted by (2) sonication; (3) lysozyme; and (4) lysozyme + EDTA. Animals fed a high-grain diet had lower carboxymethylcellulase andxylanase but higher amylase activities in the rumen. Blending ruminal solids with buffer and combining the filtrate with cheese-cloth-filtered ruminal fluid produced higher polysaccharide-degrading activities per unit of DM compared ...
30227002
Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies.
A new liquid marker, cobalt-ethylenediamine tetraacetic acid (EDTA), and two solid markers, chromium (Cr) and cerium (Ce) mordanted plant cell walls, were investigated. Synthesis and methods of analysis are described for the markers. The Cr- and Ce-cell wall complexes were tested for stability to EDTA, hydrochloric acid and rumen microorganisms. Plant cell walls were rendered indigestible by mordanting with Cr and 98% of the marker remained on the fibre after a simulated sequence (in vitro) of digestion. Ce-mordanted cell walls were 35% digestible in vitro using a rumen culture, and 56% of the marker could be washed off the remaining fibre. Treatment with EDTA removed all Ce and 15% of the Cr. Hydrochloric acid (0.01M) had a negligible effect on the removal of Cr from the cell walls, whereas 0.1M acid removed, on average, 10% of the marker. Losses of Cr from the mordant may be related to the quality of the preparation. Co-EDTA was found to be comparable to Cr-EDTA. The urinary excretion of Cr and Co was 2–3% in most animals except in rabbits, which excreted as much as 30% of the liquid markers in the urine.
73556868
The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage
A method is proposed for estimating the percentage of dietary protein that is degraded by microbial action in the rumen when protein supplement is added to a specified ration. The potential degradability, p , is measured by incubating the supplement in artificial-fibre bags in the rumen and is related to incubation time, t , by the equation p = a+b (1 – e -ct ). The rate constant k , measuring the passage of the supplement from the rumen to the abomasum, is obtained in a separate experiment in which the supplement is combined with a chromium marker which renders it completely indigestible. The effective percentage degradation, p , of the supplement, allowing for rate of passage, is shown to be p = a +[ bc/(c+k) ] (1- e -(e+k)t ) by time, t , after feeding. As t increases, this tends to the asymptotic value a+bc /( c+k ), which therefore provides an estimate of the degradability of the protein supplement under the specified feeding conditions. The method is illustrated by results obtained with soya-bean meal fed as a supplement to a dried-grass diet for sheep. The incubation measurements showed that 89% of the soya-bean protein disappeared within 24 h and indicated that it was all ultimately degradable with this diet. When the dried grass was given at a restricted level of feeding the allowance for time of retention in the rumen reduced the estimate of final degradability to 71% (69% within 24 h). With ad libitum feeding there was a faster rate of passage and the final degradability was estimated to be 66% (65% within 24 h).
83783038
Comparison of sweet white lupin seed, canola meal and soybean meal as protein supplements for lambs
Western-Canadian grown sweet white lupin seed (LS), canola meal (CM) and soybean meal (SM) were compared in situ and in digestibility and feedlot experiments using Romanov × Suffolk lambs. Barley-based (75.5% as fed) diets were isonitrogenous (15.5% crude protein, CP) with LS, CM or SM as protein source. Sunflower hulls were substituted as necessary for protein supplement to ensure the diets were isonitrogenous. The LS used in this trial was relatively low in alkaloids (0.03%), as compared with other lupins, and high in manganese (2347 mg kg−1). In situ, the effective rumen degradability of protein of LS was higher than that of either CM or SM. Rates of DM and protein disappearance were also higher for LS than for CM and SM. Digestibilities of DM organic matter, energy and nitrogen were higher (P   0.05) among the supplements in digestibilities of starch or NDF. No differences (P > 0.05) were found in feed conversion or DM intake of th...
25607576
The effect of feed intake and body weight on purine derivative excretion and microbial protein supply in sheep.
Urinary excretion of purine derivatives (PD) was used to estimate the microbial N (MN) supply to sheep in three experiments designed to examine the effects of DMI and BW on the efficiency of microbial N supply (EMNS) to the host animal. In Exp. 1, four sheep of about 45 kg BW were given 328, 656, 984, and 1313 g of DM/d of a hay/concentrate diet in a Latin square design. Excretion of PD per kilogram of digestible organic matter intake (DOMI) increased with intake, and EMNS increased from 12.0 to 28.3 g of MN/kg of OM digested in the rumen (DOMR). In Exp. 2, 19 sheep ranging from 22 to 73 kg BW were all offered 820 g of DM/d of the same diet as that fed in Exp. 1. Although DM digestibility was relatively constant, PD excretion varied from 4.5 to 13.5 mmol/d and EMNS from 8 to 36 g of MN/kg of DOMR, both inversely related to animal BW. In Exp. 3, five sheep of 48 to 57 kg BW were given a different diet at 702, 966, or 1,237 g of DM/d. Purine derivative excretion per kilogram of DOMI increased with the DMI:BW ratio. Calculated EMNS ranged from 23 to 35 g of MN/kg of DOMR. Pooled data from all experiments showed EMNS to be related to the DMI:BW ratio. It is suggested that the DMI:BW ratio defines the ruminal digesta passage rate and hence outflow of microbial protein. The results imply that the EMNS for a given diet is not constant, but changes with intake.
37168140
Effect of dietary or abomasal supplementation of exogenous polysaccharide-degrading enzymes on rumen fermentation and nutrient digestibility.
The effect of site of supplementation of a mixture of two crude preparations (Enzyme C and Enzyme X) of exogenous polysaccharide-degrading enzymes (EPDE) was studied in vivo using four ruminally and duodenally cannulated heifers (Exp. 1). The treatments were as follows: control (no EPDE), EPDE supplied through the diet (EF, 47.0 g/d), and EPDE infused continuously into the abomasum (EA, 41.6 g/d). Enzyme treatment increased the concentration of soluble reducing sugars (P < .05) and decreased NDF content (P < .05) in the treated feed, but this did not increase the rate or extent of in sacco disappearance of DM from the feed. Compared with control, ruminal fermentation was not affected by EF, but abomasal infusion increased (P < .05) rumen ammonia levels and shifted ruminal VFA patterns. Ruminal carboxymethylcellulase (CMCase) and xylanase activities were not affected by treatment. Abomasal infusion increased (P < .05) duodenal xylanase activity as compared with control and EF, but apparent digestion of DM, NDF, and CP were not affected by treatment. Negligible levels of CMCase and amylase reached the duodenum. During an in vitro experiment (Exp. 2), abomasal stability of the two EPDE was studied over a range of pH from 3.39 to .85, with or without pepsin. Carboxymethylcellulase activity (in Enzymes C and X) and beta-glucanase activity (in Enzyme C) were largely unstable against pepsin proteolysis (P < .001) and low pH (P < .001). Xylanase and amylase activities were resistant to pepsin but irreversibly inactivated at low pH. These two experiments showed that abomasal supplementation of EPDE did not successfully supply cellulases and amylases to the intestine, due partially to their limited resistance to low pH and pepsin proteolysis. Although EPDE significantly increased the level of xylanase activity at the duodenum, this did not significantly improve total tract digestion.
4460110
Alfalfa saponins affect site and extent of nutrient digestion in ruminants.
Alfalfa saponins isolated by ethanol extraction and partial acid hydrolysis were intraruminally administered to sheep to investigate the biological activities and nutritional implications in ruminants. Mature wethers fitted with ruminal, duodenal and ileal cannulas were fed a concentrate or roughage diet formulated to be isonitrogenous and isoenergetic. Microbial fermentation and nutrient degradation in the rumen were reduced by saponins. Total protozoal count in the rumen was reduced 34 and 66% by saponins at levels of 2 and 4% dietary dry matter, respectively. Bacterial nitrogen flow to the duodenum was reduced 20 and 30% in the same sequence. Apparent digestion coefficients of organic matter, hemicellulose and cellulose in the total digestive tract were increased by saponins in sheep fed concentrate diets. Fractional digestion coefficients of organic matter, hemicellulose, cellulose and nitrogen were reduced in the stomach while they were increased in the small intestine by saponins in both diets. Saponins inhibited microbial fermentation and synthesis in the rumen and altered the sites of nutrient digestion in sheep.
26103838
Synthesis of microbial protein in ruminally cannulated cows fed alfalfa silage, alfalfa hay, or corn silage.
Six ruminally cannulated cows were used in an experiment with a 3 x 3 Latin square design. Three all forage diets-alfalfa silage, alfalfa hay, or corn silage plus 2.2% urea (DM basis)-were fed for ad libitum intake four times daily. The microbial protein marker 15NH3 and the liquid marker Cr-EDTA were infused continuously into the rumen for 72 and 48 h, respectively; the solid marker, Yb-labeled forage, was dosed into the rumen twice daily for 60 h. Pool sizes of ruminal NAN were determined by emptying the rumen. Proportions of bacterial N formed from NH3 were 57, 46, and 82% for the alfalfa silage, alfalfa hay, and corn silage diets, respectively. For all diets, flows of microbial NAN with the liquid and solid phases were about equal. Although feed NAN in the liquid pool was only 12% of ruminal feed NAN, 30% of feed NAN that escaped the rumen flowed with the liquids. Flow of microbial NAN was highest for corn silage (243 g/d) and lowest for alfalfa hay (212 g/d); microbial NAN represented 50% (alfalfa silage and hay) and 76% (corn silage) of total NAN flow. Proportions of NAN intake that were degraded in the rumen were 61, 56, and 57% for alfalfa silage, alfalfa hay, and corn silage (without urea N), respectively; these values were lower than those reported by the NRC. Total flows of NAN from the rumen were 472, 424, and 321 g/d for the alfalfa silage, alfalfa hay, and corn silage diets, respectively. Use of liquid (Cr-EDTA) and solid (Yb) markers to compute the rate of passage of microbial protein proved to be less variable than regression of 15N enrichment of bacterial NAN over time.
22147092
Role of rumen protozoa in nitrogen digestion in sheep given two isonitrogenous diets.
1. The effect of protozoa on digestion in the rumen was studied using either defaunated or faunated sheep. 2. Six wethers, each fitted with rumen and simple duodenal cannulas, were given two isonitrogenous diets containing either lucerne (Medicago sativa) hay (diet L) or sodium hydroxide-treated wheat straw (diet S). The diets were given in eight equal portions per day at 3-h intervals. The mean intake of dry matter, 53 g/kg body-weight0.75 per d, was similar for the two diets and each diet had a similar digestible organic matter content. Diet L promoted a large protozoal population and was rich in nitrogen sources of low rumen-degradability, while diet S supported a smaller protozoal population and was rich in rumen-degradable N. 3. Digesta flow at the duodenum was estimated by means of a dual-marker technique using chromium-mordanted lucerne hay and polyethylene glycol as markers. The microbial flow at the duodenum was estimated using diaminopimelic acid (DAPA), nucleic-acid purine bases (PB) and 35S incorporation simultaneously. The different microbial markers were compared in the defaunated sheep. Protozoal N contribution was estimated in faunated sheep. 4. Defaunated sheep had lower rumen ammonia concentrations and molar proportions of butyric acid than faunated sheep, but they had higher molar proportions of propionic acid. 5. Rumen organic matter digestion was reduced by defaunation, but this decrease was compensated for by increased intestinal digestion. 6. There was a net increase of N flow (approximately 10 g/d) between mouth and duodenum in defaunated sheep. This was explained by increases in both microbial and dietary N flows from the rumen compared with faunated sheep. 7. The influence of protozoa on solid- and liquid-phase retention times in the rumen is discussed, as well as the protozoal contribution to microbial N flow in the duodenum of faunated sheep.
95572955
Changes in saponin content and composition during the ensilage of alfalfa (Medicago sativa L.)
Abstract Two varieties of alfalfa ( Medicago sativa L.) were ensiled under laboratory conditions after being treated with formic acid or after wilting for different times. Intact saponins, using an HPLC method, were determined in the starting material and after ensiling. The presence of two saponins were detected and measured in the experiment using the variety Hodoninka and three saponins in the second experiment using the variety Palava. Soyasaponin I was present in both varieties, whilst the two other saponins, designated as saponin A and saponin B, had chromatographic properties consistent with glycosides, of medicagenic acid. Significant decreases in saponin concentrations were observed after ensiling varying from 12% to 100%. Soyasaponin I was found to be relatively stable, while saponin A was not detected after the first week of ensiling. Treatment with formic acid stabilised saponin B and soyasaponin I for the variety Palava in contrast to the other treatments.
4594029
Influence of foliage from African multipurpose trees on activity of rumen protozoa and bacteria.
Samples and extracts of foliage from African multipurpose trees were screened for their effects on rumen protozoa and bacteria with a view to predicting their safety as feed supplements and for identifying species with potential antiprotozoal activity. The species tested were Acacia aneura, Chamaecytisus palmensis, Brachychiton populneum, Flindersia maculosa, Sesbania sesban, Leucaena leucocephala and Vernonia amyedalina. Antimicrobial effects were mild except for S. sesban, which was highly toxic to rumen protozoa in vitro, and A. aneura, which was toxic to rumen bacteria. The antiprotozoal factor in S. sesban was apparently associated with the fraction of the plant containing saponins. When S. sesban was fed to sheep, protozoal numbers fell by 60% after 4 d, but the population recovered after a further 10 d. In vitro experiments demonstrated that washed protozoa from later times were no more resistant to S. sesban than on initial exposure, suggesting that other micro-organisms, probably the bacteria, adapted to detoxify the antiprotozoal agent. Thus S. sesban may be useful in suppressing protozoa and thereby improving protein flow from the rumen, but only if the bacterial metabolism of the antiprotozoal factor can be avoided.
84727969
Effects of Yucca Shidigera extract on feed utilization by equine weanlings
Summary Reports in the literature suggest that dietary supplementation with water soluble extract of Yucca shidigera can reduce biological ammonia emissions from livestock in confinement. Because a reduction in environmental ammonia in equine housing facilities would benefit both human and animal health, the effects of Y. shidigera extract(YSE) on equine nitrogen metabolism were examined in this experiment. The addition of 100 ppm Y. shidigera extract to a 75% hay, 25% grain, lysine-deficient feed resulted in a significant increase in fecal nitrogen excretion by weanling Thoroughbreds and therefore a decrease in the apparent digestibility of dietary nitrogen. The proportion of fecal nitrogen that was water soluble increased (p A reduction in ambient ammonia in equine housing facilities may be desirable from several health perspectives. Environmental ammonia is noxious to both animals and man, and may provoke respiratory irritation and compromise. 6. , 29. Soluble compounds extracted from Yucca shidigera have recently been reported to reduce airborne ammonia concentrations in livestock production facilities when added directly to manure or incorporated into livestock feeds. 3. , 29. Althohgh free ammonia production may increase in the presence of a water soluble extract of Y. shidigera, ammonia in digesta and fecal materials apparently binds to the steroid saponins (sarsapogenin, smilagenin, hecogenin) found in the extract. 19 The most convenient method for introducing saponins into equine waste would be via the feed. Dietary saponins are apparently neither absorbed nor metabolized by ruminants or nonruminants, 7. , 10. , 27. although their ingestion may be associated with improved feed utilization and rates of growth. 18. , 27. However, it is not clear whether increased production efficiency resulted from metabolic effects attributable to saponins or from a reduction in animal stress accompanying a reduction in ambient ammonia concentrations. In the equine, growth efficiency is dependent on effective reutilization of a portion of the cecal and colonic ammonia derived from the hydrolysis of urea secreted into the intestine 11 Significant binding of ammonia to saponins within the cecum and colon could impair nitrogen economy and be detrimental to growing horses. On the other hand, increased urease hydrolysis of recycled urea could compensate for a saponin-induced reduction in the free ammonia content ofdigesta. Live yeast culture preparations may stimulate urease activity in young horses; 13. , 14. combined supplementation with both saponins and yeast culture might maintain efficient utilization of dietary nitrogen and tissue growth while reducing ammonia emissions. This experiment was undertaken to determine whether supplementation with Y. shidigera extract (YSE) affects the digestibility of dietary nutrients, the production of fecal ammonia, the efficiency of utilization of dietary nitrogen or growth in young horses. In order to ease the detection of any responses, particularly in the absence of any dose-response data, nitrogen-replete but lysine-deficient diets were used. The possibility that supplemental live yeast culture (YC) added with the saponins-emiched extract might beneficially interact with any effects of the saponins was also examined.