The effect of benzoic acid with or without a direct-fed microbial on the nutrient metabolism and gas emissions of growing pigs.

Diet formulation as a strategy to improve economic and nutritional efficiency may be combined with nonnutritive feed additives, such as organic acids, specifically benzoic acid, and direct-fed microbials, to further improve nutrient utilization in pigs. Therefore, the objective of this trial was to investigate the effect of supplementing benzoic acid with or without a direct-fed microbial on the nutrient metabolism and emissions of ammonia, hydrogen sulfide, carbon dioxide, and methane from the manure of growing pigs. Feeding a diet containing 0.3% benzoic acid did not affect nutrient digestibility but reduced urinary nitrogen excretion, which resulted in improved nitrogen retention compared to the basal diet. Furthermore, benzoic acid reduced urine and manure pH, contributing to reduced manure ammonia emissions. However, supplementing the direct-fed microbial alongside benzoic acid attenuated these effects.