Potential rapid bioassay for Alimet (R) using a metironine Escherichia coli auxotroph

摘要

A potential rapid bioassay for methionine hydroxy analog (MHA) feed additive (Alimet(R)) was examined using a methionine auxotroph E. coli strain. Bacterial cells were grown in minimal media containing a concentration range of 0 to 26.8 muM of either L-methionine or MHA as Alimet 1 Increasing either methionine or MHA concentration increased the growth rate of the methionine auxotroph. The estimated substrate affinities for methionine compared to MHA were not significantly different (P > 0.13) and the maximum growth rate estimates were also similar (P > 0.34). Methionine and MHA standard curves yielded linear responses (R-2 = 0.96) to increasing concentrations of the respective substrate. Based on these results it appears that the E. coli methionine auxotroph would have potential utility for further development of a rapid bioassay of Alimet(R).