Survival of a recombinant rumen bacterium in the rumen of sheep

摘要

Survival of the recombinant rumen bacterium Butyrivibrio fibrisolvens NO4, expressing an exogenous xylanase and erythromycin resistance, was assessed in vitro and in vivo. Selective enumeration of the recombinant strain from indigenous rumen bacteriawas performed using an erythromycin-supplemented anaerobic medium. When incubated in vitro with mixed rumen bacteria and protozoa obtained from sheep, the numbers of the recombinant strain stabilised at 10~3/ml (48 h). When incubated with mixed microbesfrom the goat rumen, strain NO4 disappeared 48 h after inoculation. The presence of protozoa in the culture tended to decrease the numbers of strain NO4 ten-fold compared to bacteria alone. In vivo, numbers declined rapidly after inoculation, and the recombinant strain was no longer detectable in the sheep rumen after 144 h.