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The in vitro uptake and metabolism of peptides and amino acids by five species of rumen bacteria
Author(s) -
Ling J.R.,
Armstead I.P.
Publication year - 1995
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1995.tb02831.x
Subject(s) - streptococcus bovis , amino acid , rumen , bacteria , biology , biochemistry , metabolism , peptide , fermentation , genetics
J. R. LING AND I.P. ARMSTEAD. 1995. Streptococcus bovis JB1, Prevotella ruminicola B 1 4, Selenomonas ruminantium Z108, Fibrobacter succinogenes S85 and Anaerovibrio lipolytica 5S were incubated with either 14 C‐peptides (mol. wt, 200–1000) or 14 C‐amino acids to compare their rates of uptake and metabolism. In experiment 1, the bacteria were grown and incubated in a complex medium, but no uptake of 14 C‐labelled substrates occurred. When casein digest was omitted, uptake rates of 14 C‐peptides were different ( P < 0·01) with each species, but nil for 14 C‐amino acids. In experiment 2, to minimize the effects of non‐radiolabelled peptides and amino acids, defined and semi‐defined media were used. Patterns of 14 C‐peptide uptake resembled those of experiment 1. The 5‐min rate for Strep. bovis JB1 was almost twice that of P. ruminicola B 1 4, though by 15 min they were similar and threefold greater than other species; that of A. lipolytica 5S was especially low. Incubations with 14 C‐amino acids resulted in a wide range ( P < 0·01) of uptake rates; after 5 min P. ruminicola B 1 4 possessed the lowest and Strep. bovis JB1 the highest, but after 15 min, that of Sel. ruminantium Z108 was even higher. All bacteria, with the exception of P. ruminicola B 1 4, assimilated 14 C‐amino acids faster ( P < 0·01) than 14 C‐peptides. Only Strep. bovis JB1 and P. ruminicola B 1 4 were capable of extensively metabolizing 14 C‐peptides, but all five species metabolized 14 C‐amino acids; there was evidence of substantial degradation and some synthesis. Calculations suggest that peptides could supply up to 43%, and amino acids 62% of the N requirements of rumen bacteria.