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Dietary Intervention of Benzoic Acid for Intestinal Health and Growth of Nursery Pigs
Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA
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Animals 2024, 14(16), 2394; https://doi.org/10.3390/ani14162394 (registering DOI)
Submission received: 17 July 2024
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Revised: 6 August 2024
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Accepted: 14 August 2024
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Published: 18 August 2024
(This article belongs to the Special Issue Feed Ingredients and Additives for Swine and Poultry)
Simple Summary
Benzoic acid has been supplemented in feeds to improve intestinal health and the growth rate of nursery pigs. Benzoic acid, a colorless crystalline organic compound, consists of a benzene ring with a carboxyl substituent, representing the simplest form of aromatic carboxylic acid. In pig feeds, benzoic acid primarily influences the small intestine rather than the large intestine of pigs, as benzoic acid does not require degradation in the stomach or beyond the small intestine. Benzoic acid possesses acidic properties, making it an effective feed additive in pig production through its antimicrobial action by reducing pH in feed and digesta in the gastrointestinal tract, positively modulating intestinal microbiota and enhancing nutrient utilization and intestinal health in pigs. Benzoic acid supplementation also decreases urinary pH through the production of hippuric acid and reduces ammonia emissions, which can positively affect the conditions of barns considering the intense pig production systems. However, depending on the levels of benzoic acid, its impact on growth is not always consistent. Thus, this review investigated the functional roles of benzoic acid on the intestinal health, nutrient utilization, and growth performance of nursery pigs, determined the optimal dose level of benzoic acid on the growth rate in nursery pigs, and compared the efficacy of benzoic acid and other acids, aiming to clarify the potential benefits of benzoic acid in pig feeds.
Abstract
The objectives of this review are to investigate how benzoic acid can mitigate the negative effects of weaning stress, improve the intestinal microbiota, intestinal health, and growth of nursery pigs, determine the optimal dose level of benzoic acid for the growth rate in nursery pigs, and compare the efficacy of benzoic acid and other acids in pig feeds. After weaning, pigs are exposed to less lactose and solid feed with high acid-binding capacity at infrequent intervals, causing an increase in digesta pH, reducing protein digestion, and increasing ammonia-producing bacteria in the stomach. Benzoic acid supplementation has improved the intestinal health and growth of nursery pigs through its antimicrobial properties and pH reduction in the digesta. The positive modulation of luminal microbiota in the small intestine of pigs by benzoic acid improves intestinal morphology and enhances nutrient utilization, especially nitrogen, of nursery pigs. Benzoic acid supplementation of up to 1% in feeds also increases hippuric acid contents in the urine of nursery pigs, decreasing urinary pH, which is related to ammonia emission and barn conditions in intensive pig production. Supported by the beneficial impacts of benzoic acid, the growth performance of nursery pigs was also improved. However, excessive benzoic acid (over 2.5% up to 5%) in feeds reduces the growth performance of nursery pigs. Thus, this review conducted a meta-analysis of the results from 16 papers to determine the optimal dose level of benzoic acid for body weight gain of nursery pigs, which was found to be 0.60%. The efficacy of benzoic acid was similar to that of other organic acids, including citric acid, fumaric acid, formic acid, and formate salts. Collectively, benzoic acid supplementation can positively modulate the luminal and mucosal microbiota in the small intestine, increase nutrient utilization and intestinal health, decrease urinary pH, and improve the growth performance of nursery pigs.
Keywords:
benzoic acid; organic acids; growth performance; intestinal health; swine
