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

The Journal of General and Applied Microbiology

Ryoji Onodera¹  Mohammad Ruhul Amin¹ 

[1] Laboratory of Animal Nutrition and Biochemistry, Division of Animal Science, Miyazaki University

关键词: benzoic acid;    metabolism;    phenylacetic acid;    phenylalanine;    phenyllactic acid;    phenylpropionic acid;    rumen bacteria;    rumen protozoa;   

DOI  :  10.2323/jgam.43.1

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

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 12h. Phe and some other related compounds in both supernatants and microbial hydrolysates of the incubations were analysed by HPLC. The net degradation rate (μmol/g 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.

【 授权许可】

Unknown