Why is Acidification needed?

Introduction:

Using low-dose antibiotics as feed additives can enhance poultry and swine performance. However, such practices have led to bacterial resistance and antibiotic residues in animal-derived foods. Consequently, there has been a shift towards finding replacements for antibiotics as growth promoters (AGPs). Among the various alternatives, organic acids have emerged as a significant option. Acidifiers have gained attention as viable alternatives to antibiotics in poultry farming.

Acidifiers: A Natural Alternative to Antibiotics for Poultry Farmers

What are Acidifiers?

Acidifiers, including organic acids and their salts, are natural compounds used to lower the pH in the gastrointestinal tract (GIT) of poultry, thereby improving digestion and health. These acids can be categorized into three primary groups:

1. Short-chain Fatty Acids (SCFAs) (C1-C7):

- Benefits: Improve gut health by enhancing beneficial bacteria growth and inhibiting pathogens.

2. Medium-chain Fatty Acids (MCFAs) (C7 - C10):

- Benefits: Have strong antimicrobial properties and serve as energy sources for the gut cells.

3. Tricarboxylic Acids (TCAs):

- Benefits: Improve mineral absorption and overall gut function.

Classification of Acidifiers and Their Used Salts and Derivatives

Benefits of Acidifiers:

Improved Gut Health: Acidifiers reduce the pH in the GIT, which discourages the growth of harmful bacteria like E. coli and Salmonella. They support a healthy balance of gut microbiota, promoting beneficial bacteria such as Lactobacillus and Bifidobacterium.
Enhanced Nutrient Digestibility: Acidifiers activate digestive enzymes, improving the breakdown and absorption of nutrients. Better gut morphology, characterised by longer villi and deeper crypts, enhances nutrient uptake.
Inhibition of Pathogenic Bacteria: Organic acids penetrate bacterial cell walls and disrupt their metabolism, reducing pathogenic load.
Energy Source: Certain acids like butyric acid act as an energy source for intestinal cells, supporting gut health and function.

Mechanisms of Action:

pH Reduction: Acidifiers lower the pH in the GIT, creating an inhospitable environment for pathogenic bacteria while favouring beneficial microbes.
Antimicrobial Effects: Acidifiers disrupt the cell membranes of harmful bacteria, inhibiting their growth and activity

Benefits of Acidifiers:  Improved Gut Health: Acidifiers reduce the pH in the GIT, which discourages the growth of harmful bacteria like E. coli and Salmonella. They support a healthy balance of gut microbiota, promoting beneficial bacteria such as Lactobacillus and Bifidobacterium.  Enhanced Nutrient Digestibility: Acidifiers activate digestive enzymes, improving the breakdown and absorption of nutrients. Better gut morphology, characterised by longer villi and deeper crypts, enhances nutrient uptake.  Inhibition of Pathogenic Bacteria: Organic acids penetrate bacterial cell walls and disrupt their metabolism, reducing pathogenic load.  Energy Source: Certain acids like butyric acid act as an energy source for intestinal cells, supporting gut health and function. Mechanisms of Action:  pH Reduction: Acidifiers lower the pH in the GIT, creating an inhospitable environment for pathogenic bacteria while favouring beneficial microbes.  Antimicrobial Effects: Acidifiers disrupt the cell membranes of harmful bacteria, inhibiting their growth and activity

Practical Application of Acidifiers:

Incorporating acidifiers into poultry diets can be done through their salts and derivatives, such as sodium butyrate or coated forms to ensure stability and efficacy throughout the GIT. The use of encapsulated acidifiers has been shown to improve their bioavailability and effectiveness in enhancing poultry health and performance.

Dosage and Administration: The effective dosage of acidifiers varies based on the type of acid and the age of the poultry. It's important to follow manufacturer guidelines for optimal results.

Formulations and Stability: Acidifiers are available in various formulations, including free acids, salts, and coated forms. Coated acidifiers ensure stability and targeted release.

pKa Values and Minimum Inhibitory Concentrations (MIC) of Common Organic Acids

Case Studies and Research Findings:

In recent studies, various acidifiers have been evaluated for their effects on growth performance and gut health in poultry and swine. Single acidifiers, such as phosphoric, lactic, propionic, formic, citric, and butyric acids, have shown significant improvements. For instance, phosphoric and lactic acids, administered at 0.1% to 0.2% and 0.3% respectively, for 1-42 days, have been observed to decrease E. coli and Salmonella populations . Propionic acid, at a dosage of 0.5% for the same period, has increased Lactobacillus while decreasing E. coli . Similarly, formic acid at 0.5% also enhanced Lactobacillus levels and reduced E. coli, while at 0.4%, its effects were noted without additional significant data . Citric acid at 0.3% improved gut morphology , and encapsulated butyric acid at 0.03% to 0.05% showed positive outcomes although specific data were not available.

Mixtures of acidifiers have also been explored. A combination containing 17% fumaric acid, 13% citric acid, 10% malic acid, and 1.2% medium-chain fatty acids (MCFAs) at 0.06% for broilers increased IgG levels, Lactobacillus, and decreased E. coli . Formic and propionic acids used together at 0.2% to 0.4% for different growth stages of broilers also showed similar benefits . A specific mixture comprising 31% formic acid, 19% propionic acid, 26% ammonium formate, and 6% ammonium propionate at 0.3 L/1000 L in drinking water improved intestinal structure when administered from 1-42 days .

Salts of acidifiers have shown promising results as well. Sodium butyrate, used at dosages of 500 to 2000 mg/kg for 1-42 days, improved intestinal structure and increased Lactobacillus populations . Another study with sodium butyrate at 0.3 to 1.2 g/kg for 1-21 days old birds showed enhanced intestinal structure and immune response to ND vaccine .

In poultry feed, organic acids and their salts play a crucial role in maintaining feed quality and enhancing animal health. Typically, these acids or salts are included at a rate of 0.5 kg/ton to control mold and at 2.5 to 3.0 kg/ton to reduce pH and control Salmonella (Banupriya, Kathirvelan, & Patric Joshua, 2016). Studies have shown that the addition of formaldehyde in chicken feed does not affect feed intake or growth rate (Regal, 2014).

Acidifiers are often added at lower levels for preservation purposes compared to levels needed for performance enhancement. Common acid preservatives include benzoic acid, acetic acid, and their salts, such as sodium benzoate and sodium acetate. Salts are used to mitigate the corrosive effects of acids, though cost constraints must be considered. Most commercial products combine different acids and/or salts to achieve synergistic effects, making it essential to understand the specific inhibitory effects of each acid before supplementation (Gonzalez-Fandos & Herrera, 2014; Sansawat, Lee, Singh, Ha, & Kang, 2019).

Conclusion:

Acidifiers provide a natural and effective alternative to antibiotics in poultry farming. By improving gut health, enhancing nutrient digestibility, and inhibiting harmful bacteria, acidifiers contribute to healthier and more productive flocks. Implementing acidifiers into your poultry nutrition program supports sustainable and responsible farming practices.