Relative contributions of ruminal bacteria and protozoa to the degradation of protein in vitro.

摘要: Mixed ruminal microorganisms from a cow fed timothy hay and concentrate supplement (50:50) were incubated with various protein sources for 15 h (no carbohydrates or growth), deamination was studied under enzyme-limiting substrate-excess conditions (n = 3). Addition of amphotericin (10 micrograms/ml) killed protozoa decreased (P less than .05) ammonia production bacteria but it had no effect greater on casein deamination. Monensin (5 also protozoa; however, to much extent amphotericin. Antibacterial antibiotics (penicillin G, polymixin B, cephalosporin C streptomycin) greatly reduced formation casein. Isolated always produced more isolated protozoa, the difference heat-treated, particulate proteins. Heated soybean as soluble heated deaminated at faster rate by bacteria. Nonammonia-nonprotein N accumulation When incubations containing compared combinations bacteria, caused synergistic increase in decrease nonammonia-nonprotein N. These results suggest: proteins primarily degraded bacteria; could contribute degradation insoluble, proteins; limited their ability assimilate peptides (or amino acids); low molecular weight products be fermented readily monensin toxic decreases due action