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

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.

1983 ◽  
Vol 61 (8) ◽  
pp. 2159-2168 ◽  
Author(s):  
Ruben A. Montes ◽  
Udo Blum ◽  
Allen S. Heagle ◽  
Richard J. Volk

The effects of chronic doses of ozone (O3) and rates of nitrogen (N) fertilizer on N content of ladino clover (Trifolium repens L. cv. Tillman) and tall fescue (Festuca arundinacea Schreb. cv. Kentucky 31), and on N fixation by the clover were studied during the 1979 growing season. Plants of the two species were grown (i) in pots separately, (ii) together in open-top field chambers, and (iii) in ambient air plots. Mean 7 h/day (0930–1630 h eastern daylight time) O3 concentrations for the study period were 0.03 ppm in charcoal-filtered air chambers, 0.05 ppm in nonfiltered air chambers, 0.08 ppm in nonfiltered air chambers with O3 added for 7 h/day, and 0.05 ppm in ambient air. Shoot N concentrations (milligrams per gram dry weight) for clover and fescue were not modified by O3 exposures nor by N fertilization. Higher ozone levels led to reduced system N fixation (milligrams N per pot) by clover grown separately or together with fescue. Nitrogen fixation by ladino clover grown with tall fescue was 1.4 times greater than that by the clover grown alone. Nitrogen fixation by clover as estimated by the difference method was approximately 45% lower than N fixation as estimated by the 15N dilution method. Nitrogen fixation estimated by the difference method declined significantly with increasing N fertilization. This was not the case for N fixation estimated by the 15N dilution method.


1986 ◽  
Vol 43 (2) ◽  
pp. 271-278 ◽  
Author(s):  
M. Ramanzin ◽  
E. R. Ørskov ◽  
A. K. Tuah

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.


1995 ◽  
Vol 125 (2) ◽  
pp. 253-261 ◽  
Author(s):  
A. Vanhatalo ◽  
T. Varvikko

SUMMARYRape (Brassica campestris) was labelled, during cultivation, with 15N and then prepared into rapeseed meal (RSM) and rapeseed straw (RSS). Three non-lactating cows, equipped with ruminal and Tshaped duodenal cannulae, were used to incubate both feeds in the rumen for various periods of time in mobile bags contained within larger mesh bags. Some of the mobile bags were then inserted into the duodenum and collected from the faeces. The effects of rumen incubation time and contamination by non-feed N during the rumen incubation and subsequent intestinal digestion on the intestinal feed N digestion values so obtained were assessed. The intestinal digestion of intact RSM nitrogen was also measured in vivo by dosing directly into the duodenum and measured as the net loss of excess 15N not recovered in the faeces.With RSM, microbial contamination did not affect the disappearance values of feed N from mobile bags in the rumen, the difference in the disappearance between 15N and total N (NT) being negligible. However, the decrease in the disappearance from the mobile bags in the intestine with increasing rumen incubation time tended to be smaller with 15N than with NT, resulting in significantly increasing differences between 15N and NT with increasing rumen incubation time. The average in vivo net loss within the intestine of 15N of labelled RSM was much lower (50·0%) than the 15N disappearance from the mobile bags (80·9%).With RSS, the disappearance values of 15N and NT from the mobile bags in the rumen were different. The disappearance of 15N was always higher than that of NT, and it also increased significantly more with increasing incubation time. The disappearance of 15N from the mobile bags within the intestine decreased with increasing rumen incubation time, but that of NT remained rather constant.It is concluded that the intestinal N digestion of a feed may vary significantly depending on the degree of preceding rumen degradation. Therefore, constant intestinal digestion coefficients may not be applied in the modern protein evaluation systems. With protein-rich feeds, such as RSM, the influence of non-feed N is small and does not interfere with the estimation of intestinal N digestibility by the mobile-bag method. With fibrous feeds with low N, such as RSS, intestinal N digestion values are seriously confounded by non-feed N. The present study with RSM did not confirm the correspondence between the value obtained by the mobile-bag method and that in vivo.


2005 ◽  
Vol 81 (1) ◽  
pp. 57-65 ◽  
Author(s):  
A. R. Askar ◽  
J. A. Guada ◽  
J. Balcells ◽  
A. de Vega ◽  
C. Castrillo

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.


1985 ◽  
Vol 54 (2) ◽  
pp. 473-481 ◽  
Author(s):  
T. Varvikko ◽  
J. E. Lindberg

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.


Author(s):  
W.M. van Straalen ◽  
C. Salaün

In modern protein evaluation systems the protein unit (PU) of a feedstuff and the requirement of PU is expressed as true protein assumed to be absorbed from the small intestine. Total PU supply originates from feed protein escaping rumen degradation and from microbial protein synthesised in the rumen. Escape feed PU is calculated from crude protein (CP) multiplied by the escape CP fraction, amino acid content of escape CP and small intestinal digestibility of escape amino acids. Microbial PU is calculated from the energy source for microbial growth multiplied by the efficiency by which this energy is used for microbial CP synthesis, amino acid content of microbial CP and the digestibility in the small intestine of microbial amino acids.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jung Eun Huh ◽  
Seunghee Han ◽  
Taeseon Yoon

Abstract Objective In this study we compare the amino acid and codon sequence of SARS-CoV-2, SARS-CoV and MERS-CoV using different statistics programs to understand their characteristics. Specifically, we are interested in how differences in the amino acid and codon sequence can lead to different incubation periods and outbreak periods. Our initial question was to compare SARS-CoV-2 to different viruses in the coronavirus family using BLAST program of NCBI and machine learning algorithms. Results The result of experiments using BLAST, Apriori and Decision Tree has shown that SARS-CoV-2 had high similarity with SARS-CoV while having comparably low similarity with MERS-CoV. We decided to compare the codons of SARS-CoV-2 and MERS-CoV to see the difference. Though the viruses are very alike according to BLAST and Apriori experiments, SVM proved that they can be effectively classified using non-linear kernels. Decision Tree experiment proved several remarkable properties of SARS-CoV-2 amino acid sequence that cannot be found in MERS-CoV amino acid sequence. The consequential purpose of this paper is to minimize the damage on humanity from SARS-CoV-2. Hence, further studies can be focused on the comparison of SARS-CoV-2 virus with other viruses that also can be transmitted during latent periods.


2001 ◽  
Vol 281 (4) ◽  
pp. G1034-G1043 ◽  
Author(s):  
Kousei Ito ◽  
Hiroshi Suzuki ◽  
Yuichi Sugiyama

Multidrug resistance-associated protein 3 (MRP3), unlike other MRPs, transports taurocholate (TC). The difference in TC transport activity between rat MRP2 and MRP3 was studied, focusing on the cationic amino acids in the transmembrane domains. For analysis, transport into membrane vesicles from Sf9 cells expressing wild-type and mutated MRP2 was examined. Substitution of Arg at position 586 with Leu and Ile and substitution of Arg at position 1096 with Lys, Leu, and Met resulted in the acquisition of TC transport activity, while retaining transport activity for glutathione and glucuronide conjugates. Substitution of Leu at position 1084 of rat MRP3 (which corresponds to Arg-1096 in rat MRP2) with Lys, but not with Val or Met, resulted in the loss of transport activity for TC and glucuronide conjugates. These results suggest that the presence of the cationic charge at Arg-586 and Arg-1096 in rat MRP2 prevents the transport of TC, whereas the presence of neutral amino acids at the corresponding position of rat MRP3 is required for the transport of substrates.


1995 ◽  
Vol 89 (4) ◽  
pp. 405-415 ◽  
Author(s):  
R. L. Sidebotham ◽  
J. H. Baron ◽  
J. Schrager ◽  
J. Spencer ◽  
J. R. Clamp ◽  
...  

1. The content and distribution of carbohydrate was examined in mucus glycopolypeptides from human antral mucosae. 2. The mean amount of carbohydrate per 1000 amino acid residues was found to be similar in glycopolypeptides with A, B or H activity. It was slightly, though significantly, less in glycopolypeptides lacking these determinants, because carbohydrate chains were of a shorter average length than in the A-, B- or H-active preparations. This difference was reflected in the sizes of oligosaccharide—alcohols released from representative glycopolypeptides with alkaline borohydride. 3. Differences between A-, B- or H-active and non-secretor glycopolypeptides in terms of the mean number of carbohydrate chains per 1000 amino acid residues were found to be small, and without significance. 4. The average number of peripheral monosaccharide units per 1000 amino acid residues was greater in A-active than in H-active, and least in non-secretor, glycopolypeptides. This order was reversed for monosaccharide units incorporated into skeletal (core plus backbone) structures. The difference in each case was statistically significant. 5. These findings suggest that the increased risk of peptic ulcer associated with blood group O and non-secretor status is unlikely to be attributable to an inherent deficiency in the protective mucus layer, linked to differences between mucins that are associated with A, B or H activity. Other hypotheses linked to infection with Helicobacter pylori are examined.


1988 ◽  
Vol 47 (1) ◽  
pp. 105-110 ◽  
Author(s):  
P. K. Bhargava ◽  
E. R. Ørskov ◽  
T. K. Walli

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.


Sign in / Sign up

Export Citation Format

Share Document