Degradation of Amino Acids and Peptides by Mixed Rumen Micro‐Organisms

Prins, R. A.; Gestel, J. C. van Hal‐van; Counotte, G. H. M.

doi:10.1111/j.1439-0396.1979.tb01226.x

Cited by 33 publications

(18 citation statements)

References 11 publications

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“…NH 3 production rates from the different substrates at 2 mg/ml in mixed ruminal digesta were consistent with previous observations that casein is more rapidly degraded than most other proteins (4) and that the uptake and deamination of amino acids is the rate-limiting step in casein catabolism (30,53). This is the first time differences in rates of breakdown have been seen with different peptide mixtures, although numerous instances have been observed with pure peptides (5,48,53).…”

Section: Discussionsupporting

confidence: 77%

Ammonia Production by Ruminal Microorganisms and Enumeration, Isolation, and Characterization of Bacteria Capable of Growth on Peptides and Amino Acids from the Sheep Rumen

Eschenlauer¹,

McKain²,

Walker³

et al. 2002

Appl Environ Microbiol

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Excessive NH 3 production in the rumen is a major nutritional inefficiency in ruminant animals. Experiments were undertaken to compare the rates of NH 3 production from different substrates in ruminal fluid in vitro and to assess the role of asaccharolytic bacteria in NH 3 production. Ruminal fluid was taken from four rumenfistulated sheep receiving a mixed hay-concentrate diet. The calculated rate of NH 3 production from Trypticase varied from 1.8 to 19.7 nmol mg of protein ؊1 min ؊1 depending on the substrate, its concentration, and the method used. Monensin (5 M) inhibited NH 3 production from proteins, peptides, and amino acids by an average of 28% with substrate at 2 mg/ml, compared to 48% with substrate at 20 mg/ml (P ‫؍‬ 0.011). Of the total bacterial population, 1.4% grew on Trypticase alone, of which 93% was eliminated by 5 M monensin. Many fewer bacteria (0.002% of the total) grew on amino acids alone. Nineteen isolates capable of growth on Trypticase were obtained from four sheep. 16S ribosomal DNA and traditional identification methods indicated the bacteria fell into six groups. All were sensitive to monensin, and all except one group (group III, similar to Atopobium minutum), produced NH 3 at >250 nmol min ؊1 mg of protein ؊1 , depending on the medium, as determined by a batch culture method. All isolates had exopeptidase activity, but only group III had an apparent dipeptidyl peptidase I activity. Groups I, II, and IV were most closely related to asaccharolytic ruminal and oral Clostridium and Eubacterium spp. Group V comprised one isolate, similar to Desulfomonas piger (formerly Desulfovibrio pigra). Group VI was 95% similar to Acidaminococcus fermentans. Growth of the Atopobium-and Desulfomonas-like isolates was enhanced by sugars, while growth of groups I, II, and V was significantly depressed by sugars. This study therefore demonstrates that different methodologies and different substrate concentrations provide an explanation for different apparent rates of ruminal NH 3 production reported in different studies and identifies a diverse range of hyper-ammonia-producing bacteria in the rumen of sheep.Deamination of amino acids in the rumen, which leads to the loss of NH 3 across the ruminal wall, is one of the main causes of inefficient N retention by ruminants (23). For many years, it had been assumed that NH 3 formation was carried out by some of the numerically predominant species of ruminal bacteria that had been identified as producing NH 3 weakly from protein or protein hydrolysates (3). However, Russell and his colleagues (7,8,12,35,36) calculated that these bacteria did not have sufficient activity to account for observed in vitro rates of NH 3 production by the mixed population in their cattle, and they isolated bacteria which were much less numerous than the others but which possessed a specific activity of NH 3 production from Trypticase which was an order of magnitude greater than that of the other species. Moreover, these bacteria, unlike the others, were gram positive and highly sen...

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Section: Discussionsupporting

confidence: 77%

Ammonia Production by Ruminal Microorganisms and Enumeration, Isolation, and Characterization of Bacteria Capable of Growth on Peptides and Amino Acids from the Sheep Rumen

Eschenlauer¹,

McKain²,

Walker³

et al. 2002

Appl Environ Microbiol

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“…The Phe degradation (apparent disappearance) rate in vitro in rumen microbial suspensions of cattle was 0.290 mM/h (Chalupa, 1976), whereas a higher value (0.540 mM/h) was reported using the rumen fluids of dairy cows (Prins et al, 1979). In this experiment, the Phe degradation (apparent disappearance) rate by B and BP from goat rumen were 0.063 and 0.082 mM/h, respectively.…”

Section: Resultsmentioning

confidence: 75%

“…The degradation rates of some amino acids have been investigated by other researchers previously (Chalupa, 1976;Prins et al, 1979). The Phe degradation (apparent disappearance) rate in vitro in rumen microbial suspensions of cattle was 0.290 mM/h (Chalupa, 1976), whereas a higher value (0.540 mM/h) was reported using the rumen fluids of dairy cows (Prins et al, 1979).…”

Section: Resultsmentioning

confidence: 99%

“…These values are close to our values with B in this experiment. Prins et al (1979) suggested that the disappearance of amino acids in vitro depends on the diet of the inoculum donor, the form in which the amino acids were added and the presence or absence of other energy sources during incubation.…”

Section: Resultsmentioning

confidence: 99%

“…In the mid and late 1970s, researchers published data on the apparent degradation rates of amino acids by mixed ruminal microorganisms (Chalupa, 1976;Prins et al, 1979) and five major genera of rumen bacteria (Scheifinger et al, 1976) through the measurement of ammonia production.…”

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confidence: 99%

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In vitro metabolism of phenylalanine by ruminal bacteria, protozoa, and their mixture.

Amin

Onodera

1997

J. Gen. Appl. Microbiol.

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An in vitro study was conducted to examine the metabolism of phenylalanine (Phe) by mixed rumen bacteria (B), mixed rumen protozoa (P), and a combination of the two (BP). Rumen microorganisms were collected from fistulated goats fed lucerne cubes (Medicago sativa) and a concentrated mixture twice a day. Microbial suspensions were anaerobically incubated at 39°C for 12 h. Phe and some other related compounds in both supernatants and microbial hydrolysates of the incubations were analysed by HPLC. The net degradation rate (µmollg microbial nitrogen) of Phe in B was about 1.5-fold higher than that in P. Phe was converted mainly into phenylacetic acid (PAA) and unknown compound(s) that presumably involved tyrosine in B, P, and BP during the 12h incubation period. Small amounts of benzoic acid (BZA), and traces of phenylpropionic acid (PPR) and phenyllactic acid (PLA) were also produced from Phe. PAA production in B was found to be higher than that in P, whereas it was significantly higher in BP. Although BZA production was less than one-tenth that of PAA production, it was higher in P than in B and BP. PPR was detected in both B and BP, but not in P. PLA was detected only in B. The production of unknown compound(s) was higher in B than in P and BP.

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Uptake of small neutral peptides by mixed rumen microorganisms in vitro

Broderick

Wallace²,

McKain³

1988

J Sci Food Agric

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A BS T R A CTThe metabolism of a range of neutral di-and oligopeptides and peptide p-nitroanilides was investigated in strained ruminal fluid diluted with anaerobic buffer. Peptide uptake was assayed by decrease in fluorescamine-reactive material in extracellular fluid, and peptide p-nitroanilide hydrolysis by diazotisation of the released p-nitroaniline. Addition of glucose and dithiothreitol did not alter uptake of di-or trialanine. Calculated V,, for di-and trialanine uptake were 1-4 and 1.9 nmol min-I mg DM-I, corresponding K , were 0.30 and 0.14 mmol litre-'. Dipeptide uptake was 0.72 to 0.90 nmol min-I mg DM-I, except f o r glycylproline, which was taken up at 0-43 nmol min-1 mg DM-I. There was a wider range for tripeptide uptake (0-5 to 1.6 nmol min-I mg DM-I), with trialanine being taken up most rapidly. Tetra-and pentaalanine were removed at 0.93 and 0.71 nmol min-I mg DM-I. Uptake of amino acid residues as alanine oligopeptides was two to three times more rapid than uptake as dialanine. These data suggest that peptides would accumulate in rumen fluid during hydrolysis of rapidly degraded proteins, but peptide uptake would exceed rate of release from more slowly degraded proteins. Rates of hydrolysis of eight peptide p-nitroanilides were 0.56 to 1.53 nmol min-I mg DM-I, and were of similar magnitude to uptake of di-and tripeptides; proline-containing p-nitroanilides were also more slowly metabolised.

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Degradation of Amino Acids and Peptides by Mixed Rumen Micro‐Organisms

Cited by 33 publications

References 11 publications

Ammonia Production by Ruminal Microorganisms and Enumeration, Isolation, and Characterization of Bacteria Capable of Growth on Peptides and Amino Acids from the Sheep Rumen

Ammonia Production by Ruminal Microorganisms and Enumeration, Isolation, and Characterization of Bacteria Capable of Growth on Peptides and Amino Acids from the Sheep Rumen

In vitro metabolism of phenylalanine by ruminal bacteria, protozoa, and their mixture.

Uptake of small neutral peptides by mixed rumen microorganisms in vitro

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