FIG 1.

Comparison of growth yields for C. perfringens intestinal strains cultured at 37°C in DMEM with or without glucose or sialic acid supplementation. Fifteen intestinal strains (Table 1) were grown for 24 h in control DMEM, DMEM with 1.6 mM sialic acid (SL), DMEM with 1.6 mM glucose (GL), DMEM with 16 mM sialic acid (SH), or DMEM with 16 mM glucose (GH), as indicated. (A) Growth yields of the surveyed intestinal strains. Compared to that for equivalent growth in control DMEM, the OD₆₀₀ of all carbohydrate-supplemented cultures increased significantly (*, P < 0.05). SH and GH cultures also had significantly higher growth yields than those of similar SL and GL cultures, respectively (* with bar, P < 0.05). (B) Growth yields of the eight intestinal strains in Table 1 that do and the seven intestinal strains in Table 1 that do not carry the nanI gene. Only when cultures were supplemented with the higher Neu5Ac concentration were growth yields slightly increased for strains with the nanI gene versus strains without the nanI gene (*, P < 0.05). All experiments were repeated three times, and mean values are shown. The error bars indicate standard deviations.