scholarly journals The simultaneous estimation of the amounts of protozoal, bacterial and dietary nitrogen entering the duodenum of steers

1984 ◽  
Vol 51 (1) ◽  
pp. 111-132 ◽  
Author(s):  
J. E. Cockburn ◽  
A. P. Williams
Keyword(s):  
Latin Square ◽  
Diaminopimelic Acid ◽  
Simultaneous Estimation ◽  
Rumen Bacteria ◽  
Bacterial Protein ◽  
Flow Estimation ◽  
Dietary Nitrogen ◽  
Amino Acid Profiling ◽  
Dietary Casein ◽  
Microbial N

1. Four steers were given straw and tapioca diets, twice daily, in a 4 x 4 Latin-square design. These diets, containing 4.2 g nitrogen/kg dry matter (DM), were further supplemented with either urea, decorticated groundnut meal (DCGM), untreated (UT) casein or formaldehyde-treated (FT) casein to give a total of 19.7 g N/kg DM and 10.5 MJ/kg DM daily.2. Concurrent samples of rumen bacteria and protozoa and abomasal digesta were collected for each period of the experiment and the concentrations of 2-aminoethyl phosphonic acid (AEPA), diaminopimelic acid (DAPA), total nitrogen (TN), total phosphorus (TP), amino acids and hexosamines were determined in the dried preparations. The nature of the dietary supplements had little effect on the concentrations of most of these constituents or on the total protozoal numbers.3. Abomasal digesta samples marked with polyethylene glycol (PEG) and chromic oxide for flow estimation were collected over 24 h, and the proportions of protozoal-N, bacterial-N and microbial-N estimated simultaneously using the markers AEPA, DAPA and RNA respectively. These digesta-N components were also estimated using an amino acid profiling (AAP) method which gave, in addition, estimates of the dietary and endogenous components. For the diets containing casein, the proportion of dietary casein was estimated directly using casein-P as a marker.4. Estimates of the respective mean proportions of microbial-N in abomasal digesta non-ammonia-N (NAN) for the diets containing urea, DCGM, UT casein or FT casein were: AEPA 0.56, 0.32, 0.27 and 0.16; DAPA 0.88, 0.70, 0.81 and 0.57; RNA 0.98, 0.85, 0.92 and 0.53.5. Giving FT casein significantly (P< 0.001) increased the flow of casein-N at the abomasum and a significantly (P< 0.001) greater proportion of casein-N was found in abomasal NAN (0.51v.0.09) where FT rather than UT casein was given.6. The AAP method gave results for the proportions of microbial- and dietary-N (where casein was given) which were, in general, slightly lower than those obtained using RNA and casein-P as markers. Agreement with estimates of bacterial protein (from DAPA) and of protozoal protein (from AEPA) was less satisfactory.7. Comparisons of the various estimates of the proportions of microbial-N in abomasal digesta suggested that the results obtained for protozoal-N by AEPA were overestimates. AEPA was found in mixed rumen bacteria which may have accounted in part for these overestimates. However, AEPA was not detected in any of the dietary ingredients.

scholarly journals Net transfer of nutrients to the duodenum and disappearance ofn-alkanes in the reticulo-rumen and the hindgut of sheep fed grass/legume combinations

2012 ◽  
Vol 109 (10) ◽  
pp. 1765-1778 ◽  
Author(s):  
Abdelhafid Keli ◽  
Genaro Olmos ◽  
Antonio de Vega ◽  
José A. Guada
Keyword(s):  
Organic Matter ◽  
Latin Square ◽  
Rumen Bacteria ◽  
Lolium Rigidum ◽  
Microbial Synthesis ◽  
Fibre Intake ◽  
Wimmera Ryegrass ◽  
Ryegrass Hay ◽  
Microbial N ◽  
Net Transfer

An experiment was carried out to examine the effect of increasing the proportion of Wimmera ryegrass hay in a lucerne hay-based diet on net transfer of nutrients to the intestine, and on the disappearance ofn-alkanes in the reticulo-rumen and the hindgut of sheep. Following a latin square design, four adult ewes were fed 1:0, 0·33:0·67, 0·67:0·33 and 0:1 proportions of legume and grass. Increasing the proportion of ryegrass in the diet linearly decreased the intake of DM (P= 0·017), organic matter (P= 0·021) and N (P= 0·001). However, neutral-detergent fibre intake was not affected (P= 0·148), nor was its digestibility coefficient (P>0·10). Diet had no effect on duodenal flows of nutrients (P>0·10), although the proportion of N intake (NI) recovered at the duodenum as non-NH3N (NAN) increased linearly withLolium rigidumin the diet (P= 0·002). Full recovery of NI as NAN was achieved at NH3concentrations in the rumen below 110 g/l. Microbial N contribution to NAN varied in a quadratic manner (P< 0·05) with the proportion of grass in the diet, although efficiency of microbial synthesis was not affected (P>0·10). Duodenal recovery of consumedn-alkanes was not affected by diet and was complete for those present in higher concentrations in the forages. Isolated rumen bacteria contained significant amounts ofn-alkanes, contributing to the duodenal flow of these hydrocarbons in variable proportions depending on the diet consumed.

Estimation of amounts of microbial and dietary nitrogen compounds entering the duodenum of cattle

1978 ◽  
Vol 90 (3) ◽  
pp. 557-568 ◽  
Author(s):  
R. H. Smith ◽  
A. B. McAllan ◽  
D. Hewitt ◽  
Patricia E. Lewis
Keyword(s):  
Specific Activity ◽  
Soya Bean ◽  
Diaminopimelic Acid ◽  
Inorganic P ◽  
Dietary Nitrogen ◽  
Daily Sampling ◽  
Bean Meal ◽  
Soya Bean Meal ◽  
Made In ◽  
Microbial N

SummaryYoung steers with rumen and simple duodenal cannulas were given diets of approximately equal amounts of flaked maize and hay (A) or of flaked maize and straw supplemented with decorticated groundnut meal (DCGM) (B), fishmeal (C), heated soya-bean meal (D) or raw soya-bean meal (E) or of dried grass (F). A cow with rumen and re-entrant duodenal cannulas was given diets of hay and dairy cubes.Some steers received doses of32P-labelled inorganic phosphate twice daily with their concentrate feed. This led to small diurnal variations in inorganic P–32P specific activity but at similar daily sampling times the32P specific activity in rumen bacterial nucleic acids reached a steady state after dosing for about 4 days. Contributions of microbial-N to non-ammonia-N (NA-N) entering the duodenum were then estimated by comparing nucleic acid32P/NA-N ratios in related samples of rumen bacteria and duodenal contents. Similar estimates were made in these and other animals using α-, ε-diaminopimelic acid (DAP) and ribonucleic acid (RNA) as bacterial markers.Estimates for steers given diets A, B, C and F based upon ‘32P-labelled RNA nucleotides’ were, on average, 85% of those based upon total RNA. The differences were attributed mainly to the latter being elevated by the presence of small amounts of dietary RNA. When RNA-based estimates of the proportion of microbial-N in NA-N in duodenal contents for these and other steers which were nearly free of protozoa were multiplied by 0·85 (‘adjusted RNA’) the values were, on average, similar to those based upon DAP. Similar estimates for the cow based upon ‘adjusted RNA’ measurements were, however, about twice those based upon DAP, probably because the cow contained a high protozoal population and the DAP based, method did not account for protozoal N.For some steers total flows at the duodenum of organic matter (OM), microbial-N (mean based upon ‘adjusted RNA’ and DAP) and residual food N were estimated by reference to chromic oxide. Average values for g microbial-N synthesized/kg OM truly digested in the rumen for the different diets ranged from 15 to 22 (mean 20). Mean degradabilities of food N (residual food N at duodenum/N intake) were 0·57, 0·71, 0·71, 0·70 and 0·84 for diets A, B, C, D and E respectively. No differences between diets were significant atP< 0·05.

scholarly journals Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation

1988 ◽  
Vol 60 (2) ◽  
pp. 339-353 ◽  
Author(s):  
J. M. Dawson ◽  
C. I. Bruce ◽  
P. J. Buttery ◽  
M. Gill ◽  
D. E. Beever
Keyword(s):  
Live Weight ◽  
Period Change ◽  
Diaminopimelic Acid ◽  
Growth Responses ◽  
Microbial Protein ◽  
Total N ◽  
Mean Values ◽  
Rumen Microbes ◽  
Dietary Nitrogen ◽  
Microbial N

1. Ryegrass (Lolium perenne cv. Cropper) silage was given to four Friesian steers (initial live weight (LW) 172 kg) alone or with a fishmeal supplement (150 g fresh weight/kg silage dry matter (DM)) in a balanced two- period change-over design. The dietary components were the same as those used in a recent experiment by Gill et al. (1987). All diets were offered hourly at 24 g DM/kg LW.2. Fishmeal supplementation increased dietary nitrogen intake (P < 0.01) and significantly increased the flow of total N (P < 0.01), non-ammonia N (NAN) (P < 0.01) and amino acids (P < 0.05) at the duodenum. The increased supply of NAN to the duodenum was due largely (67%) to increased flow of undegraded dietary protein.3. Microbial protein production was estimated simultaneously with 15N, diaminopimelic acid (DAPA) and a novel technique using L-[4,5-3H]leucine. Estimates varied with the marker and source of microbial isolate but mean values indicated that microbial N flow was significantly increased by fishmeal supplementation (P < 0.05). The use of L-[4,5-3H]leucine as a microbial marker is justified and its possible advantages over other markers are discussed.4. The efficiency of microbial protein synthesis was significantly increased from 30.8 g N/kg organic matter apparently digested in the rumen (OMADR) to 54.3 gN/kg OMADR by fishmeal supplementation (P < 0.01). However, this indicates that relatively high efficiencies can be achieved with unsupplemented high quality silage supplied continuously. Rumen degradable N (RDN) supply was significantly increased by fishmeal supplementation (P < 0.05) but apparent efficiency of capture of RDN by rumen microbes was not significantly increased.5. Attempts were made to investigate the source of N utilized by the microbes on the two diets by intrarumen infusions of (15NH4)2SO4 and L-[4,5-3H]leucine but these were confounded by rumen-mixing problems. Findings obtained suggest that a lower proportion of microbial N may have been derived from rumen ammonia when the silage was supplemented with fishmeal but no differences in the extent of direct incorporation of leucine into microbial protein were observed. This could indicate an increase in microbial peptide uptake on the fishmeal-supplemented diet. However, evidence was also obtained suggesting that the improvement in microbial protein synthetic efficiency with supplementary fishmeal was also due to the provision of a more continuous supply of nitrogenous substrates for microbial growth, as a result of hourly feeding.6. The results are related to the increased growth responses attained by fishmeal supplementation of this silage in the experiment of Gill et al. (1987).

scholarly journals Digestion and synthesis in the rumen of sheep given diets supplemented with free and protected oils

1983 ◽  
Vol 49 (3) ◽  
pp. 419-432 ◽  
Author(s):  
J. D. Sutton ◽  
R. Knight ◽  
A. B. McAllan ◽  
R. H. Smith
Keyword(s):  
Protein Synthesis ◽  
Linseed Oil ◽  
Latin Square ◽  
Coconut Oil ◽  
Sodium Caseinate ◽  
Diaminopimelic Acid ◽  
Microbial Protein ◽  
Total N ◽  
Microbial Protein Synthesis ◽  
Microbial N

1. Six wether sheep were each provided with a permanent cannula in the rumen and re-entrant cannulas in the proximal duodenum.2. In a preliminary study, the sheep consumed 200 g hay and 400 g concentrates supplemented with up to 40 g linseed oil, coconut oil or cod-liver oil daily. Feed was refused at higher levels of supplementation.3. Five of the sheep were used in a 5 × 5 Latin-square experiment. They were given 200 g hay and 400 g concentrates alone (B) or supplemented with 40 g linseed oil (L), coconut oil (C), protected linseed oil or protected coconut oil daily. The protected oils were prepared by emulsifying the free oils with formaldehyde-treated sodium caseinate. Formaldehyde-treated sodium caseinate was also included in the other three diets.4. Digestion in the stomach was measured by spot sampling duodenal digesta, using chromic oxide-impregnated paper as the marker. Microbial flow at the duodenum was measured by use of both diaminopimelic acid (DAPA) and RNA as microbial markers.5. Both the free oils had broadly similar effects despite their very different fatty acid compositions. Digestion in the stomach of organic matter (OM) was reduced from 0·48 (diet B) to 0·29 (diets L and C) and that of neutral-detergent fibre from 0·50 (diet B) to 0·19 (diet L) and 0·12 (diet C). The molar proportions of acetic acid and n-butyric acid were decreased and that of propionic acid was increased. Protozoal numbers were reduced by 78% (diet L) and 90% (diet C). The flow of total nitrogen and microbial N was increased by both oils and the efficiency of microbial protein synthesis (g N/kg OM apparently digested in the rumen) was increased from 30 (diet B) to 85 (diet L) and 74 (diet C) when based on DAPA and from 41 (diet B) to 94 (diet L) and 81 (diet C) when based on RNA. The efficiency when based on true digestion of OM (g N/kg OM truly digested in the rumen) was increased from 23 (diet B) to 46 (diet L) and 44 (diet C) when based on DAPA and from 29 (diet B) to 49 (diet L) and 46 (diet C) when based on RNA. The amounts of microbial OM (g/d) at the duodenum were increased from 68 (diet B) to 124 (diet L) and 106 (diet C) when based on DAPA and from 92 (diet B) to 136 (diet L) and 115 (diet C, non-significant) when based on RNA.6. When the oils were given in the protected form, the effects on digestion in the stomach were reduced but not eliminated. No significant increases in the amount of total N or microbial N at the duodenum were established, though there was a tendency for an increase in the efficiency of microbial protein synthesis with protected linseed oil. The results suggested that the method of protection used reduced the effects of the oils on rumen digestion and synthesis but was only partially successful in preventing hydrogenation of the fatty acids.7. It is concluded that free oils can markedly increase the efficiency of microbial protein synthesis, possibly by their defaunating effect, and that this may enhance the potential for using non-protein-N on oil-supplemented diets.

The influence of lasalocid and cationomycin on nitrogen digestion in sheep: Comparison of methods for estimating microbial nitrogen

1991 ◽  
Vol 71 (2) ◽  
pp. 389-399 ◽  
Author(s):  
L. Gomez ◽  
J. P. Jouany ◽  
B. Lassalas ◽  
C. Bogaert
Keyword(s):  
Control Diet ◽  
Latin Square ◽  
Ammonia Nitrogen ◽  
Diaminopimelic Acid ◽  
Design Experiment ◽  
Dietary Proteins ◽  
Dietary Nitrogen ◽  
Microbial Nitrogen ◽  
Sheep Rumen

An in vivo study was carried out to evaluate the effect of a new ionophore (cationomycin) on nitrogen digestion compared with lasalocid. Three diets based on forage were given (a control diet, a "cationomycin" diet, a "lasalocid" diet) to six sheep fitted with rumen duodenal and ileal cannulae over three different periods in a Latin square design experiment. The supply of lasalocid or cationomycin (33 mg kg−1) decreased (P < 0.05) the breakdown of dietary proteins in the rumen and lowered the microbial protein synthesis whatever the microbial marker used (diaminopimelic acid or purine bases). The duodenal and ileal flows of organic matter (OM), ammonia nitrogen (NH3-N), nonammonia nitrogen, and amino acids (AA) were not affected by the ionophore addition. We could not use the AA profile method to estimate the microbial contribution to the duodenal flow of nonammonia nitrogen because of the strong similarities in AA composition of the feed and the rumen microbial sample. The efficiency of microbial synthesis was significantly (P < 0.05) decreased by cationomycin, and tended to decrease with lasalocid. Only lasalocid increased the digestibility of dietary nitrogen in all the digestive tract. Key words: Ionophore, lasalocid, cationomycin, digestion, nitrogen, sheep, rumen

The simultaneous use of ribonucleic acid, 35S, 2,6-diaminopimelic acid and 2-aminoethylphosphonic acid as markers of microbial nitrogen entering the duodenum of sheep

1978 ◽  
Vol 39 (1) ◽  
pp. 165-179 ◽  
Author(s):  
J. R. Ling ◽  
P. J. Buttery
Keyword(s):  
Fish Meal ◽  
Barley Grain ◽  
Soya Bean ◽  
Diaminopimelic Acid ◽  
Estimation Methods ◽  
Mean Values ◽  
Advantages And Disadvantages ◽  
Bean Meal ◽  
Soya Bean Meal ◽  
Microbial N

1. Three sheep, each fitted with a ruminal cannula and duodenal re-entrant cannulas were given three isonitrogenous, isoenergetic diets in a Latin-Square design. Each diet contained (/kg) approximately 400 g N as white fish meal, soya-bean meal or urea and approximately 600 g dry matter (dm) was barley grain. The diets were fed continuously and supplied about 28 g N/d.2. Total duodenal digesta was collected manually for 72 h and the proportions of microbial N in that digesta were simultaneously estimated for all sheep using RNA, radioactive sulphur (35S), diaminopimelic acid (DAPA) and aminoethylphosphonic acid (AEPA) as markers.3. Three of the estimation methods showed that the variable source of dietary N had the greatest (RNA P < 0.05, 35S P < 0.005, DAPA P < 0.1) effect on the proportions of microbial N in duodenal digesta, though differences between sheep accounted for some variation.4. These methods also ranked the diets in the order: urea > soya-bean meal > fish meal with respect to the proportions of digesta N that were microbial in origin; the respective mean values for these diets with the different markers were: RNA 0.98, 0.70, 0.56; 35S 0.92, 0.64, 0.54; DAPA 0.80, 0.47, 0.42.5. AEPA was found to be present in substantial quantities not only in isolated rumen protozoa, but also in dietary and bacterial material; an observation that invalidated its further use as a protozoal marker.6. Calculations using values obtained from the 35S procedure showed that the proportions of dietary N degraded within the rumen were 0.38, 0.43 and 0.89 for the white fish meal, soya-bean meal and barley respectively.7. The marker methods are compared and their advantages and disadvantages (real and apparent) are discussed. It is concluded that where microbial N estimates of a more general and comparative nature are required, the use of RNA as a marker is probably adequate. Where information for more exacting purposes is required, the use of 35S appears to be more appropriate.

The effect of dietary asynchrony on rumen nitrogen recycling in sheep

1995 ◽  
Vol 1995 ◽  
pp. 70-70 ◽  
Author(s):  
P. Holder ◽  
P.J. Buttery ◽  
P.C. Garnsworthy
Keyword(s):  
Nitrogen Deficiency ◽  
Nitrogen Sources ◽  
Ammonia Concentration ◽  
Rumen Bacteria ◽  
Dietary Energy ◽  
Nitrogen Recycling ◽  
Dietary Nitrogen ◽  
Dietary Nutrients ◽  
Rumen Nitrogen ◽  
Energy Components

Recent work (Sinclair et al. 1993) has suggested that synchronising the rate of rumen breakdown and availability of dietary energy and nitrogenous components can increase capture of rumen degradable nitrogen and improve efficiency of microbial protein synthesis. For rumen bacteria to function efficiently they require a supply of both energy and nitrogen sources together i.e a synchronous diet. Nitrogen recycling between the blood and the rumen is a major contributor to the nitrogen economy of the animal and supplies substantial quantities of nitrogen to the rumen bacteria (Kennedy & Milligan 1980). The amount of nitrogen recycled to the rumen is diet dependant. This dependency may not solely be due to the levels of dietary nutrients but also to their rate of breakdown and availability to the rumen bacteria. The predominant mechanism controlling nitrogen recycling between the blood and the rumen appears to be rumen ammonia concentration It has been suggested that the recycling of nitrogen between the blood urea pool and the rumen ammonia pool may be able to compensate for periods of dietary nitrogen deficiency in the rumen due to the asynchrony of availability of the nitrogen and energy components to the rumen bacteria.

Critical evaluation of diaminopimelic acid and ribonucleic acid as markers to estimate rumen pools and duodenal flows of bacterial and protozoal nitrogen

1996 ◽  
Vol 76 (4) ◽  
pp. 587-597 ◽  
Author(s):  
P. H. Robinson ◽  
J. G. Fadel ◽  
M. Ivan
Keyword(s):  
Ribonucleic Acid ◽  
Critical Evaluation ◽  
Diaminopimelic Acid ◽  
Published Data ◽  
Rumen Bacteria ◽  
Low Protein ◽  
Animal Metabolism ◽  
Barley Silage ◽  
Pool Sizes ◽  
N Pool

Whole animal mathematical models have become widely accepted as the only practical way to incorporate the vast amount of published data into conceptual models of animal metabolism. The ability to accurately predict dietary N requirements of dairy cows depends upon the ability to accurately measure digesta flow and identify the origins of its N. Four lactating Holstein cows were fed a low-protein (9.8% CP of DM) ration of 28.6% timothy silage, 27.2% whole crop barley silage, and 44.2% gram-based concentrate (DM basis). This was supplemented with 1.3 kg d−1 of ground barley mixed with either no protein supplement, 1.11 kg of soybean meal, 0.67 kg of blood meal or 0.20 kg of urea. Rumen bacteria and protozoa were isolated and assayed for components. Rumen ingesta were manually evacuated to estimate rumen pool sizes, and duodenal digesta were sampled to estimate intestinal flow. Use of diaminopimelic acid (DAPA) was judged to result in rumen bacterial N pool sizes that were quantitatively reasonable and reflective of expected changes due to treatments. Conversely, use of ribonucleic acid (RNA) was judged to underestimate the rumen microbial N pool size and result in biologically implausible differences due to treatments. Use of DAPA was judged to slightly underestimate duodenal flow of bacterial N and suggested changes due to treatments consistent with expectations. In contrast, RNA suggested biologically implausible differences in duodenal flow of bacterial N due to treatments. A novel mathematical procedure utilizing both DAPA and RNA to estimate rumen pool sizes and intestinal flows of bacterial and protozoal N did not provide biologically plausible estimates thereby demonstrating that at least some of the assumptions relative to use of DAPA and RNA are not correct. Key words: Rumen bacteria, protozoa, diaminopimelic acid, ribonucleic acid, phosphatidylcholine

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