In vivo gene expression at 12 h (A), 24 h (B), and 36 h (C) relative to the highest level of expression in vitro by real-time PCR analysis. Total bacterial RNA extracted from strain ZY05719 grown in LB broth media was used as the template to assay the in vitro expression levels of the 10 newly identified genes. SPF minipigs were employed as model to study the in vivo expression levels. Pigs were inoculated intravenously with strain ZY05719, and bacterial cells recovered from blood at 12 h, 24 h, and 36 h post-inoculation were considered as in vivo growth bacteria. Total bacterial RNAs extracted from in vivo growth bacterial cells were further analyzed by real-time PCR. To determine whether RNA expression level is induced or upregulated under in vivo conditions, we compared in vivo gene expression with the highest level of expression in vitro. The standard deviations are presented from three pigs each, blood collected at 12, 24 and 48 h. 1, ss-1616; 2, trag; 3, nlpa; 4, srt; 5, cwh; 6, hprk; 7, ysirk; 8, ss-1955; 9, sdh; 10, ss-1298; gapdh was used as reference gene.