Validation of use of purine bases as a microbial marker by15N labelling in growing lambs given high-concentrate diets: effects of grain processing, animal age and digesta sampling site

2005 ◽  
Vol 81 (1) ◽  
pp. 57-65 ◽  
Author(s):  
A. R. Askar ◽  
J. A. Guada ◽  
J. Balcells ◽  
A. de Vega ◽  
C. Castrillo
Keyword(s):  
Sampling Site ◽  
Barley Grain ◽  
Barley Straw ◽  
Purine Bases ◽  
Rumen Degradation ◽  
Grain Processing ◽  
Microbial Nitrogen ◽  
The Difference ◽  
Endogenous Contamination ◽  
Microbial N

AbstractThe origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pelleted concentrate plus barley straw (C) or whole barley grain plus protein supplement (WB). Six lambs from each treatment were slaughtered at 10 and 30 days post weaning after15N labelling of microbial nitrogen (N) and PB. Microbial contribution to digesta non-ammonia N (NAN) and PB was lower (P< 0·01) when estimated from duodenal rather than abomasal samples (0·36 v. 0·52 (s.e.d. 0·021) for NAN and 0·47 v. 0·77 (s.e.d. 0·029) for PB) as a result of endogenous contamination. In comparison with15N, total PB/N led to higher estimates (P< 0·01) of microbial contribution to abomasal NAN in WB treatment (0·62 v. 0·46 s.e.d. 0·049). The difference was removed after correcting for microbial PB, while this effect was not observed with < the C diet, resulting in a marker by diet interaction (P< 0·05). Abomasal PB flow increased (P< 0·1) from 10 to 30 days after weaning mainly due to the higher proportion of microbial PB (0·70 v. 0·81 (s.e.d. 0·047)). Rumen apparent PB degradation did not differ between diets in older lambs, but it was proportionally 0·39 lower for WB treatment (P< 0·05) in younger lambs. When the microbial PB flow was estimated indirectly from labelled microbial N and the PB/N ratio of bacterial extracts the estimates were in agreement with those derived from PB-15N in the WB treatment but resulted in unrealistic values in lambs on diet C. Results suggest that significant proportions of dietary PB can escape rumen degradation which may lead to overestimation of microbial contribution to abomasal NAN when the PB/N ratio is used as marker. The extent of the overestimation is affected by the lamb age and grain processing.

scholarly journals Determination of rumen microbial-nitrogen production in sheep: a comparison of urinary purine excretion with methods using 15N and purine bases as markers of microbial-nitrogen entering the duodenum

1996 ◽  
Vol 75 (5) ◽  
pp. 699-709 ◽  
Author(s):  
J. F. erez ◽  
J. Balcells ◽  
J. A. Guada ◽  
C. Castrillo
Keyword(s):  
Urinary Excretion ◽  
Basal Diet ◽  
Barley Grain ◽  
Rumen Content ◽  
Purine Derivatives ◽  
Flow Measurements ◽  
Mean Values ◽  
Purine Bases ◽  
Microbial Nitrogen ◽  
Microbial N

The present study compares estimates of rumen microbial-N production derived from duodenal flow measurements (15N and purine bases) with those from measurements of the urinary excretion of purine derivatives. Four Rasa Aragonesa ewes fitted with simple cannulas in the rumen and proximal duodenum were used. Four diets consisting of 550 g lucerne (Medicago sativa) hay/d as sole feed or supplemented with 220, 400 and 550 g rolled barley grain/d were given in a 4 x 4 random factorial arrangement. Duodenal digesta flows were determined by the dual-phase marker technique during continuous intraruminal infusions of Co-EDTA and Yb-acetate. Microbial contribution to the non-NH3N (NAN)flow was estimated from 15N enrichment and purines: N ratio in duodenal digesta and bacterial fractions isolated from the rumen content. Whole tract organic matter (OM) digestibility and duodenal flow of OM and NAN increased (P<0·001) with the level of barley supplementation. Digestible OM intake ranged from 19·0 to 42·7 g/kg metabolic weight (W0·75) and the duodenal flow of purine bases and the urinary excretion of allantoin increased Linearly (P < 0·001) from minimum values of 7·47 (SD 1·524)and 4·65 (SD 0·705) mmol/d respectively on the basal diet to 18·20 (SD 1·751) and 11·62 (SD 0·214) mmol/d on the 400 g barley diet; a further increase in barley supplementation decreased both variables (13/50 (SD 2/334) and 8/77 (SD 0/617) mmol/d respectively). Urinary excretion of uric acid and hypoxanthine showed a slight but significant increase (P < 0·05) over all levels of barley. Molar recoveries of duodenal purine bases as purine derivatives or allantoin in the urine were 0·78 (SD 0·156) and 0·65 (SD 0·130) respectively. The increase on barley supplementation significantly augmented microbial-N, but large differences between microbial markers employed were observed. Mean values of microbial-N estimated from the duodenal purine bases or urinary allantoin excretion were on average 18 and 29% lower than those measured by 15N.

Microbially corrected amino acid composition of rumen-undegraded feed protein and amino acid degradability in the rumen of feeds enclosed in nylon bags

1986 ◽  
Vol 56 (1) ◽  
pp. 131-140 ◽  
Author(s):  
T. Varvikko
Keyword(s):  
Amino Acid ◽  
Incubation Time ◽  
Average Rate ◽  
Barley Straw ◽  
Dilution Method ◽  
Time Effects ◽  
Rumen Degradation ◽  
The Difference ◽  
Feed Protein ◽  
N Dilution Method

1. In the previous work (Varvikko & Lindberg, 1985), 15N-labelled rapeseed (Brassica napus), barley, ryegrass (Lolium perenne) and barley straw were incubated in the rumen in nylon bags for 5, 12 and 24 h and microbial nitrogen in the residues was quantified using the feed 15N-dilution method. In the present study, residual amino acids (AA) of these feeds were analysed, and microbially corrected AA of feed origin (feed AA) were estimated as the difference between total residual AA and respective microbial AA, assuming a constant AA composition for the microbial protein.2. In barley and barley-straw residues, and also in ryegrass incubated in the rumen for 24 h, very large enrich- ment by microbial N and AA-N was found. The microbial enrichment was rather small in rapeseed residues and ryegrass incubated for 5 or 12 h. During the rumen incubation, feed N and AA-N (g/kg feed dry matter (DM)) decreased very clearly in all the feeds, and feed and incubation time effects were always statistically significant (P < 0.001).3. The slow degradation of essential (E) feed AA compared with the respective non-essential (NE) AA degradation increased the proportion of feed EAA (g/kg determined feed AA) in barley and barley-straw residues. In rapeseed and ryegrass, residual feed EAA: NEAA remained very similar to the original. Branched-chain (Br) AA tended to increase proportionally in all the feed residues, suggesting these AA to be, on average, more resistant against microbial degradation in the rumen than other AA. Similarly, lysine was clearly increased in barley residues. A rumen degradation faster than the average rate caused decreased residual feed glutamic acid in rapeseed; methionine, alanine and glycine in barley; arginine and alanine in ryegrass; and methionine, asparagine and tyrosine in barley straw. Feed and incubation time effects were significant (P < 0.054–001) for feed AA (g/kg determined feed AA) grouped as EAA, BrAA or NEAA, and for most individual AA, as well as for feed AA disappearance (%) and relative amounts (%) of feed AA in the respective residual AA.4. According to present findings, AA composition of the rumen-undegraded vegetable feed residues may markedly differ, either quantitatively or qualitatively (or both), from their original AA composition. When determining the feed AA composition of nylon-bag residues, the microbial error may be very large with starchy or fibrous feeds of low protein content. The microbial AA do not, however, considerably confuse the AA determination of protein-rich feeds.

Rumen degradation of straw 2. Botanical fractions of straw from two barley cultivars

1986 ◽  
Vol 43 (2) ◽  
pp. 271-278 ◽  
Author(s):  
M. Ramanzin ◽  
E. R. Ørskov ◽  
A. K. Tuah
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Barley Straw ◽  
Ammonia Treatment ◽  
Similar Chemical Composition ◽  
Barley Cultivars ◽  
Rumen Degradation ◽  
Dry Matter Loss ◽  
Similar Chemical ◽  
The Difference

ABSTRACTTwo varieties of barley straw, Corgi and Gerbel, which varied in degradability when incubated in the rumen in nylon bags, were chosen for further examination of botanical fractions and to see how each fraction responded to treatment with ammonia. The straws were separated into leaves, internodes, nodes and chaff. The average proportions of these fractions were respectively 0·499, 0·380, 0·055 and 0·065 in Corgi straw and 0·404, 0·512, 0·059 and 0·025 in Gerbel straw. For both varieties the degradability of the botanical fractions were leaves > chaff > nodes > internodes.Despite a similar chemical composition, the dry-matter loss (DML) values of leaves, internodes and nodes of Corgi were higher than those of Gerbel straw.The differences between varieties were larger for internodes and nodes than for leaves. The difference in DML of the two varieties at 48-h incubation was 132 g/kg DM. Of this difference, 25 g were due to differences in distribution of the botanical fractions and 107 g to differences in DML of the fractions.Ammonia treatment significantly increased the DML of all fractions except the nodes. The overall improvement due to ammonia treatment of the different fraction was internode > chaff > leaves > nodes.

Feeding value of peas for backgrounding beef heifers

2003 ◽  
Vol 83 (4) ◽  
pp. 779-786 ◽  
Author(s):  
J. -Q. Chen ◽  
E. K. Okine ◽  
M. A. Price ◽  
G. R. Khorasani
Keyword(s):  
Dry Matter ◽  
Barley Grain ◽  
Barley Straw ◽  
Canola Meal ◽  
Limiting Factor ◽  
Feed Conversion ◽  
Beef Heifers ◽  
The Difference ◽  
Rumen Undegradable Protein ◽  
Feed Costs

Four diets in which peas progressively replaced barley [0% (0P), 30% (30P), 50% (50P), and 100% peas (100P)] and one in which canola meal (CM) replaced 10% of the barley, were fed to 90 beef heifers (initial weight 215.8 ± 13.8 kg). The heifers achieved average daily gains (ADGs) of 0.72, 0.80, 0.79, 0.83, and 0.76 kg d-1 on the five diets, respectively, with the difference between the 0P group and the 100P group being significant (P = 0.028). The total feed costs of gain were $0.786, 0.779, 0.799, 0.860, and 0.817 kg-1 for the five groups, respectively, with the cost of gain being significantly greater (P < 0.05) for the 100P group than for the 0P, 30P or 50P groups. The latter three were not significantly different from each other. Three rumen-cannulated steers (575 ± 56.3 kg) were used to estimate the degradability of the dry matter (DM) and N in the barley straw (BS), CM, barley grain (BG) and peas used in the feeding trial. The rumen undegradable protein (RUP) levels supplied by the five diets were 17.5, 19.0, 19.9, 21.5, and 22.5%, respectively, and all of them met the requirements of these cattle. The RUP content of peas ground through a 1-mm screen was lower than that of peas ground through 2- or 4-mm screens (P < 0.01), which were themselves not significantly different from each other (P = 0.67). The low RUP content of peas was not a limiting factor for growth in backgrounding cattle. Key words: Cattle, field peas, dry matter intake, feed conversion efficiency, rumen me

Composition of liquid-and particle-associated bacteria and their contribution to the rumen outflow

1998 ◽  
Vol 49 (5) ◽  
pp. 907 ◽  
Author(s):  
J. F. Pérez ◽  
M. Fondevila ◽  
J. Balcells ◽  
J. A. Guada
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Rumen Fluid ◽  
Phase 1 ◽  
Random Order ◽  
Barley Grain ◽  
Barley Straw ◽  
Associated Bacteria ◽  
The Difference ◽  
Urea Infusion

A method is described to estimate the composition and rumen outflow of microbes associated with liquid (LAB) and solid (SAB) digesta. Four rumen-cannulated Rasa Aragonesa ewes were given, in random order, the following 4 diets: (1) NaOH-treated barley straw, as a sole diet (700 g/day, TS); (2) NaOH-treated barley straw mixed (50 : 50) with 400 g/day of rolled barley grain (BS); (3) Diet 1 with addition of 8 g/day of urea; and (4) Diet 2 with addition of 16 g/day of urea. Co-EDTA was used as a marker for the liquid phase to estimate rumen outflow of liquid-associated purine bases (PB), and urinary purine derivatives were used as an indirect marker of total duodenal flow of PB. Solid-associated PB were calculated by the difference between both estimates. Urea infusion increased ammonia-N concentration in the rumen fluid from 4·8 to 15·9 mg/100 mL (P < 0· 05) and enhanced dry matter intake of TS diets (from 343±63· 5 to 556±41·2 g/day, P < 0·001). Significant differences were observed in the PB/N ratio of bacteria harvested from the liquid phase compared with that isolated from the solid phase (1·89±0·25 v. 1·66±0·32 mol/mg in LAB and SAB, respectively). Because of the differences observed between the liquid- and solid-associated bacteria, estimated values of bacterial N supply varied depending on which bacterial extract was used as reference. The fractional contribution of LAB and SAB to the postruminal bacteria was significantly influenced by the experimental diets, mainly through variations in the amount of LAB flowing out of the rumen.

Estimation of microbial nitrogen in nylon-bag residues by feed15N dilution

1985 ◽  
Vol 54 (2) ◽  
pp. 473-481 ◽  
Author(s):  
T. Varvikko ◽  
J. E. Lindberg
Keyword(s):  
Sample Size ◽  
Incubation Time ◽  
Microbial Contamination ◽  
Barley Grain ◽  
Microbial Colonization ◽  
Diaminopimelic Acid ◽  
Barley Straw ◽  
Total N ◽  
Time Effects ◽  
Microbial N

1. Rapeseed (Brussicu nupus), barley grain, ryegrass (Loliurnperenne) and barley straw were labelled with15N as an internal marker. The dilution of15N was used to estimate microbial N (RMN15N) in the feed residues in nylon bags incubated in the rumen for 5, 12 and 24 h. For comparative purposes, diaminopimelic acid (DAP) content of the residues was also determined and rumen microbial N (RMNDAP-N) in the feed residues calculated using DAP as a bacterial marker. The influence of two bag pore sizes (20 μm and 40 μm) with different sample sizes (1 g and 5 g respectively) was also studied.2. For all feeds, the average disappearance of15N was faster than that of total N, the difference between N and15N disappearance being marked with barley, ryegrass and barley straw. The disappearance of microbially corrected dry matter (DM; correction calculated from the15N values) was, accordingly, always faster than the uncorrected DM disappearance. Except for the bag pore/sample size effect for N disappearance, significant (P < 0.01–0.001) feed, pore/sample size and incubation-time effects were always found for the disappearance values.3. Errors (%) resulting from the microbial contamination (calculated from the15N values) in N-loss measurement with rapeseed, barley, ryegrass and barley straw, at 5, 12 and 24 h in 20 μm bags were respectively: –1.8, –3.9, –0.9; –3.8, –22.4, –3.8; –7.2, –4.1, –2.9; –164.5, –146.3, –204.6. In 40 μm bags the corresponding errors were respectively: –4.4, –1.2, –0.7; –26.1, –10.5, –3.9; –13.2, –6.4, –5.5; –221.2, –310.1, –1284.6.4. The largest residual proportions of RMN15N, RMNDAP-Nand DAP-N (% of total N) were found in barley straw, followed by barley, ryegrass and rapeseed, in that order. RMN15N(g/kg residual DM) followed the descending order: barley, ryegrass, straw, rapeseed. RMNDAP-N, (g/kg residual DM) and DAP (mg/kg residual DM) followed the descending order: barley, ryegrass, rapeseed and barley straw. Feed, pore/sample size and incubation-time effects were always significant (P < 0.001).5. With 40 μm bags RMN15Nvalues of barley, ryegrass and barley straw (expressed as % of total N or g/kg residual DM) were substantially higher than those of RMNDAP-NWith 20 μm bags the RMN15Nand RMNDAP-Nvalues were generally quite close for these feeds. With rapeseed residues, RMN15Nwas clearly lower than RMNDAP-Nwith 20 μm bags, but only small differences were found with 40 μm bags.6. A more diverse microbial colonization of feed samples was indicated in the 40 μm bags compared with the 20 μm bags. It was also noticed, consequently, that in most cases larger error resulted from the microbial contamination in 40 μm bags.

Comparison of purines and nitrogen-15 as microbial flow markers in beef heifers fed barley- or corn-based diets

2005 ◽  
Vol 85 (2) ◽  
pp. 211-222 ◽  
Author(s):  
A. N. Hristov ◽  
T. A. McAllister ◽  
D. R. Ouellet ◽  
G. A. Broderick
Keyword(s):  
Uric Acid ◽  
Volatile Fatty Acids ◽  
Xylanase Activity ◽  
Barley Grain ◽  
Neutral Detergent Fiber ◽  
Microbial Protein ◽  
Beef Heifers ◽  
Purine Derivative ◽  
Purine Bases ◽  
The Difference

The objective of this study was to estimate the contribution of microbial purine bases to duodenal purines and to purine derivatives [allantoin and uric acid (PD)] excreted in the urine. Additionally, microbial protein (MCP) flow estimated using duodenal flow of purine bases was compared to estimates using 15N as a microbial marker. Four beef heifers were fed two diets, barley silage/barley grain/soybean meal (diet B) or corn silage/corn grain/corn gluten meal (diet C), in a cross-over design study. (15NH4)2SO4 was infused in the rumen for 8 d to label ruminal microorganisms and their purine bases. Rumen contents, duodenal digesta, urine, and feces were sampled during the last 2 d of tracer infusion and for 48 h after the infusion ceased. The animals consumed more (P < 0.01) dry matter (DM), organic matter (OM), N, and neutral detergent fiber (NDF) with diet B than with diet C. Total tract digestibilities of DM, OM, and NDF were also higher (P < 0.01) with diet B. Ruminal ammonia (P < 0.01), volatile fatty acids (P < 0.05), and acetate (P < 0.01) concentrations and xylanase activity (P < 0.05) were higher with diet B compared with diet C. Flow of MCP to the duodenum was estimated from duodenal samples using purines or 15N as microbial markers, or from urinary PD excretion. The effects of diet or method of measurement on MCP flow were not significant. However, when the urinary PD method was excluded from the analysis, MCP flow was greater (by 26%; P = 0.01) when estimated using 15N vs. the purine-based method. The difference was mainly due to underestimation of the proportion of microbial N in the liquid duodenal digesta with the purine method. Feed purines contributed from 3.5 (liquid digesta phase) to 19.7% (solid digesta phase) of the total purine flow at the duodenum. 15N enrichment of urinary PD was 1.08 of the enrichment of duodenal purines, suggesting that feed purines contributed little N to urinary allantoin and uric acid in cattle. Key words: Allantoin, cattle, microbial protein synthesis, nitrogen-15, purine derivative

Multivariate micropollutants analysis in marine waters

1995 ◽  
Vol 32 (9-10) ◽  
pp. 341-348
Author(s):  
V. Librando ◽  
G. Magazzù ◽  
A. Puglisi
Keyword(s):  
Multivariate Data Analysis ◽  
Partial Least Squares Regression ◽  
Environmental Chemistry ◽  
Sampling Site ◽  
Principal Component ◽  
Least Squares Regression ◽  
Organic Micropollutants ◽  
Suspended Material ◽  
The Difference

The monitoring of water quality today provides a great quantity of data consisting of the values of the parameters measured as a function of time. In the marine environment, and especially in the suspended material, increasing importance is being given to the presence of organic micropollutants, particularly since some are known to be carcinogenic. As the number of measured parameters increases examining the data and their consequent interpretation becomes more difficult. To overcome such difficulties, numerous chemometric techniques have been introduced in environmental chemistry, such as Multivariate Data Analysis (MVDA), Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR). The use of the first technique in this work has been applied to the interpretation of the quality of Augusta bay, by measuring the concentration of numerous organic micropollutants, together with the classical water pollution parameters, in different sites and at different times. The MVDA has highlighted the difference between various sampling sites whose data were initially thought to be similar. Furthermore, it has allowed a choice of more significant parameters for future monitoring and more suitable sampling site locations.

Rumen degradation of straw 4. Selection and degradation of morphological components of barley straw by sheep

1988 ◽  
Vol 47 (1) ◽  
pp. 105-110 ◽  
Author(s):  
P. K. Bhargava ◽  
E. R. Ørskov ◽  
T. K. Walli
Keyword(s):  
Leaf Blade ◽  
Dry Matter ◽  
Leaf Sheath ◽  
Practical Significance ◽  
Barley Straw ◽  
Rumen Degradation ◽  
Whole Plant ◽  
Ad Libitum ◽  
The Mathematical Model ◽  
Selection Of

AbstractExperiments were made to study the proportion, chemical composition, and rumen degradability of the morphological components of barley straw (Corgi variety) and to study the selection of these components by sheep. The proportions in the harvested straw dry matter (DM) as leaf blade, leaf sheath, stem and chaff were 128, 314, 500 and 58 g/kg DM, respectively. The different components of straw on analysis proved to have very different concentrations of nitrogen and neutral-detergent cellulase digestibility. The leaf blades had the highest and the stems the lowest values. The degradabilities of DM in the components and in the whole straw were determined by measuring DM loss from samples incubated in nylon bags for various periods in the rumen of sheep. Responses were measured using the mathematical model p = a+b (1–e−ct) where p is DM loss, (a+b) potential degradability, c the rate constant of DM loss and t is the time of incubation. DM losses decreased in the order leaf blades > leaf sheath > whole plant > chaff > stems. Leaf blades also had the highest potential degradability and rate of degradation.In another trial, five sheep were offered unchopped barley straw ad libitum. There were five treatment periods in which sheep were allowed to leave uneaten proportionately 0·2, 0·3, 0·4, 0·5 and 0·7 of the straw on offer for assessing the animal's selection of the morphological components of that straw. The amount of leaf blade in the material consumed increased in largely a linear (P < 0·01) fashion with the amount of excess allowance. The proportion of stem eaten varied conversely. The selection of leaf sheath was less apparent. Little stem was consumed until the proportion of leaf blade in the food available decreased below proportionately 0·4. The practical significance of the study is discussed.

scholarly journals Rumen degradation and fractional outflow rates of nitrogen supplements given to cattle eating sodium hydroxide-treated straw

1986 ◽  
Vol 55 (2) ◽  
pp. 387-398 ◽  
Author(s):  
K. Amaning-Kwarteng ◽  
R. C. Kellaway ◽  
Jane Leibholz ◽  
A. C. Kirby
Keyword(s):  
Sodium Hydroxide ◽  
Cotton Seed ◽  
Relative Importance ◽  
High Intake ◽  
Protein Supplements ◽  
Rumen Degradation ◽  
Cotton Seed Meal ◽  
Meat Meal ◽  
The Difference

1. Six rumen and abomasal cannulated heifers were used to study the effects of intake on the fractional outflow rates (FOR) of chromium-mordanted cotton-seed meal (Cr-CSM) and meat meal (Cr-MM), CrEDTA, ytterbium and lignin from the rumen. Values of FOR of Cr-CSM and Cr-MM were combined with values of nitrogen disappearance from the protein supplements, placed in porous synthetic (nylon) bags and incubated within the rumen (P), to calculate effective degradation (D)of CSM and MM when fed to heifers eating sodium hydroxide-treated straw. Also, N degradation in vivo (V) was measured as the difference between abomasal N flow and the sum of flows of microbial and endogenous N.2. FOR were positively related to intake and differences between supplements were significant (p<0.01). FOR pertaining to high and low intakes respectively were 0.073 and 0.052 for Cr-CSM, 0.082 and 0.071 for Cr-MM, 0.030 and 0.023 for lignin, 0.082 and 0.073 for CrEDTA and 0, 044 and 0.035 for Yb.3. A rise of 28.8 and 13.4% in FOR of Cr-CSM and Cr-MM respectively, associated with an increase in intake from maintenance to 1.5 times maintenance, resulted in 10.7 and 2.2% reductions inD, 24 h after feeding, for CSM and MM respectively.4. With the exception of CSM at the high intake, estimates ofVwere underestimated byDand were 8.6–25.0% greater than theDvalues when time of incubation (t)= ∞. The two techniques, however, ranked the degradation of the two supplements in the same order at both levels of intake.5. Underestimation ofVbyDmay be attributable to underestimation ofP, overestimation of FOR (both resulting in underestimation ofD) or overestimation ofVdue to biases associated with the estimation of this part of the comparison. The relative importance of these factors remains to be determined.

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