Amino Acid Availability of Isolated Rumen Microbes as Affected by Protein Supplement

Wr, Burris; Nw, Bradley; Ja, Boling

doi:10.2527/jas1974.381200x

Cited by 18 publications

(7 citation statements)

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“…Mean, minimum, and maximum values and CV are presented for each type of microorganisms for each AA in Table 2. The CV of the FAB fraction were the highest for Cys, His, and Met, which also was observed Meyer et al, 1967;Ibrahim and Ingalls, 1972;Williams and Dinusson, 1973;Burris et al, 1974;Rooke et al, 1984;Hvelplund, 1986;Rahnema and Theurer, 1986;Cecava et al, 1988;Erasmus et al, 1994;Cozzi et al, 1995;Ludden and Cecava, 1995;Martin et al, 1996;Ludden and Kerley, 1997;Mabjeesh et al, 1997;Volden and Harstad, 1998;Elizalde et al, 1999;Volden et al, 1999;Korhonen et al, 2002;Robinson et al, 2002;Reynal et al, 2003;Zebeli et al, 2008;Fonseca et al, 2014.…”

Section: Resultssupporting

confidence: 58%

Amino acid composition of rumen bacteria and protozoa in cattle

Sok

Ouellet

Firkins

et al. 2017

Journal of Dairy Science

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Because microbial crude protein (MCP) constitutes more than 50% of the protein digested in cattle, its AA composition is needed to adequately estimate AA supply. Our objective was to update the AA contributions of the rumen microbial AA flowing to the duodenum using only studies from cattle, differentiating between fluid-associated bacteria (FAB), particle-associated bacteria (PAB), and protozoa, based on published literature (53, 16, and 18 treatment means were used for each type of microorganism, respectively). In addition, Cys and Met reported concentrations were retained only when an adequate protection of the sulfur groups was performed before the acid hydrolysis. The total AA (or true protein) fraction represented 82.4% of CP in bacteria. For 10 AA, including 4 essential AA, the AA composition differed between protozoa and bacteria. The most noticeable differences were a 45% lower Lys concentration and 40% higher Ala concentration in bacteria than in protozoa. Differences between FAB and PAB were less pronounced than differences between bacteria and protozoa. Assuming 33% FAB, 50% PAB, and 17% of protozoa in MCP duodenal flow, the updated concentrations of AA would decrease supply estimates of Met, Thr, and Val originating from MCP and increase those of Lys and Phe by 5 to 10% compared with those calculated using the FAB composition reported previously. Therefore, inclusion of the contribution of PAB and protozoa to the duodenal MCP flow is needed to adequately estimate AA supply from microbial origin when a factorial method is used to estimate duodenal AA flow. Furthermore, acknowledging the fact that hydrolysis of 1 kg of true microbial protein yields 1.16 kg of free AA substantially increases the estimates of AA supply from MCP.

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Section: Resultssupporting

confidence: 58%

Amino acid composition of rumen bacteria and protozoa in cattle

Sok

Ouellet

Firkins

et al. 2017

Journal of Dairy Science

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“…The amino acids of bacteria showed thus very slight deviations, though the feed particularly the nitrogen feed differed very much. Similar results have been reported by several other scientists (Weller 1964, Hoeller and Harmeyer 1964, Bergen et al 1968, Ibrahim and Ingalls 1972, Burris et al 1974. Williams and Dinusson (1973) found only slight differences in the amino acid composition of microbial protein, independent of whether or not the microbial population contained ruminal ciliated protozoa.…”

Section: Methodssupporting

confidence: 89%

The in vitro determination of the protein quality of rumen microorganisms of cows on urea-rich feed

Syväoja

Kreula

1979

AFSci

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The amino acid composition, essential amino acid index (EAA-I), pepsin-pancreatin in vitro digestibility and pepsin-pancreatin-digest-residue-index (PPDR-I) of the rumen bacterial and protozoal protein of cows fed urea and ammonium salts as their sole source of nitrogen (0-cows) or as a partial source (ULP-cows), and of cows on normal protein-rich feed (NorP-cows), were determined. The amino acid compositions of the rumen bacteria showed very slight changes even though the diets were very different. The amino acid compositions of the pure bacterial strains isolated from the rumina differed slightly. The amino acid compositions of the rumen protozoa of the ULP- and NorP-cows differed only with respect to isoleucine and tyrosine. Protozoa could be found only occasionally in the rumen of the 0-cow, there being only two species. Their nutritional significance was obviously very small. When the nutritional quality of the microbial protein was studied on the basis of its amino acid composition it was found that the EAA-I of bacteria did not differ significantly. Neither did the EAA-I of protozoa differ. The pepsin-pancreatin in vitro digestibility of protozoa was higher on all the feeds than that of bacteria. The rumen bacterial in vitro digestibility with 0-cows differed from that of the ULP-samples but not from that of the NorP-samples. The digestibility of single amino acids, With the exception of diaminopimelic acid, glycine and alanine, did not differ from the digestibility of the total amino acids. The much larger number of bacteria in the rumen of 0-cows compared with those of ULP- and NorP-cows compensates in this way for the lower digestibility of bacterial protein in 0-cows. The PPDR-I of both bacteria and protozoa were well correlated with the in vitro digestibility.

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“…When using a Rusitec, liquid-and solid-associated microbes can only be isolated at the end of the incuba- Bergen et al, 1968;Burris et al, 1974;Cecava et al, 1988;Gabel and Poppe, 1986;Hoogenraad and Hird, 1970;Hvelplund, 1986;Ibrahim and Ingalls, 1972;Meyer et al, 1967;Purser and Buechler, 1966;Storm and Orskov, 1983;Titgemeyer et al, 1989;Williams and Dinusson, 1973 (n = 21). tion period, whereas the RM fraction represents the average population of microbes leaving the system over time.…”

Section: Discussionmentioning

confidence: 99%

Effect of Total Mixed Ration Composition on Amino Acid Profiles of Different Fractions of Ruminal Microbes In Vitro

Boguhn

Kluth

Rodehutscord

2006

Journal of Dairy Science

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The objective was to study the variation in the amino acid profile of microbial fractions obtained after feeding 16 total mixed rations for dairy cows in a Rusitec. Each ration was incubated for 15 d in 3-fold replicate. The rations showed high variation in the inclusion level of different ingredients and the content of proximal nutrients, fiber fractions, and energy. Three microbial fractions were isolated by centrifugation. The reference microbes (RM) were isolated from the liquid effluent of vessels between d 7 and 15 of incubation. Solid-associated microbes (SAM) were detached with methylcellulose from feed residues after incubation, and liquid-associated microbes (LAM) were obtained from the liquid content of the vessel. Both SAM and LAM were obtained only once for each vessel at the end of the incubation period. Across all rations, significant differences were found between RM, LAM, and SAM in amino acid concentration for some, but not all, amino acids. Within each microbial fraction, significant differences in the content of amino acids were found between rations. Multiple linear regression analysis did not show that the content of a certain nutrient or the inclusion rate of single feedstuffs could be used to predict the amino acid profile of microbial protein with an adequate level of accuracy. Further studies are necessary before the supply of individual microbial amino acids to the cows' duodenum can be modeled and predicted in dependence of diet data.

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Amino Acid Availability of Isolated Rumen Microbes as Affected by Protein Supplement

Cited by 18 publications

References 0 publications

Amino acid composition of rumen bacteria and protozoa in cattle

Amino acid composition of rumen bacteria and protozoa in cattle

The in vitro determination of the protein quality of rumen microorganisms of cows on urea-rich feed

Effect of Total Mixed Ration Composition on Amino Acid Profiles of Different Fractions of Ruminal Microbes In Vitro

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