Role of benzoic, lactic and sorbic acid in in vitro swine cecal fermentation

Aim of the present study was to investigate the role of different organic acids in modulating the swine cecal microflora in an in vitro system. The acids tested were benzoic, lactic and sorbic at 0, 2000, 4000, 6000, 8000 and 10000 ppm in cecal liquor. Gas production was monitored throughout the study and after 24 hours ammonia concentration was measured. Data showed that lactic acid has been effective in promoting fermentation from 4000 ppm to 10000 ppm through a higher gas production (+35%, +42%, +61%, +75% respectively, P<0.01); benzoic acid caused a significative reduction in total gas production from 6000 ppm to 10000 ppm (-46%,-52%,-50% respectively, P<0.01); sorbic acid did not modify gas parameters. Ammonia was increased by sorbic acid at 10000 ppm (27%, P<0.05) and by lactic acid at 2000 ppm (+62%, P<0.01). These data suggest that some organic acids can positively influence swine cecal microflora in vitro fermentation.