Water Acidification in Poultry Health and Productivity

In modern poultry farming, within the current context of antibiotic restrictions, water acidification has become a key tool to strengthen intestinal health, improve performance, and reduce the incidence of digestive diseases.

During the first weeks of life, birds have an immature digestive system and a developing microbiota. In this context, water acidification helps control pathogens, stimulate consumption, and promote intestinal development.

Water acidification involves adding organic or inorganic acids to the drinking water to lower the pH and achieve positive effects both at a physical-chemical and intestinal level.

The usual dose ranges from 0.1% to 0.5% of the water volume, with the goal of maintaining the pH between 3.8 and 4.5, depending on the type of bird, age, and sanitary conditions.

Water acidification can be applied continuously or during specific critical periods, or when an outbreak of gastrointestinal diseases is detected on the farm.

Water Acidification, Organic and Inorganic Acids, and Their Benefits

It is common to work with organic and inorganic acids in the market depending on the objectives to be achieved.

• Organic Acids
  Organic acids contain carbon (C) and usually have a carboxyl functional group (-COOH). These acids come from biological sources. They are weaker compared to those with a lower pKa, which is why they can have a significant impact on the pH of the digestive tract. Common organic acids used for water acidification include formic acid, lactic acid, acetic acid, citric acid, propionic acid, among others.
• Inorganic Acids
  Inorganic acids with a low pKa are those whose acid dissociation constant is small, meaning they dissociate easily in the medium, releasing protons (H+). The most commonly used inorganic acids are phosphoric, hydrochloric, and sulfuric acids. These acids generally do not act in the intestines, as they have already dissociated earlier.

As the name implies, water acidification involves adding these acids to the drinking water of the birds to achieve two functions with corresponding benefits:

1. Physical-Chemical Correction
   • Improvement of Chlorine Efficiency
     When using chlorine to disinfect water with a pH higher than 6.5, the dissociation of hypochlorous acid will not occur, and the disinfecting capacity of added chlorine will be practically null. Therefore, acids are added to water treated with chlorine to improve the chlorine’s disinfectant capacity. If another disinfectant is used, such as hydrogen peroxide, it is not pH-dependent for disinfection. This means that the quality of disinfection is the same in both low or high pH water when using hydrogen peroxide.
   • Improvement of Digestion and Nutrient Absorption
     More acidic water favors the activation of digestive enzymes in the gastrointestinal tract of birds, improving the breakdown of food and the absorption of nutrients. In particular, lactic acid, for example, helps activate pepsin, a key enzyme for protein digestion. With more efficient digestion, birds can better utilize the nutrients in the food, leading to greater growth and production.

Protein Digestion Process

1. Proteins (in food) – Breakdown into Polypeptides:
   In birds, the protein digestion process starts in the crop, but most protein digestion occurs in the stomach. Birds have a two-part stomach:
   • Proventriculus: This is the glandular part of the stomach, where gastric juices, including acids and enzymes like pepsin, are secreted to begin breaking down proteins into polypeptides.
   • Gizzard (Ventriculus): In this muscular organ, food is further triturated and broken down, assisted by the abrasion of hard particles such as stones or sand that birds ingest and that act as teeth.
2. Polypeptides – Breakdown in the Small Intestine:
   After polypeptides are generated in the proventriculus, the process continues in the small intestine. Here, proteolytic enzymes like trypsin and chymotrypsin (produced in the pancreas) continue breaking down the polypeptides into shorter peptides.
3. Peptides – Breakdown into Free Amino Acids:
   In the small intestine, shorter peptides are further broken down by other enzymes like peptidases to release free amino acids.
4. Amino Acids – Absorption in the Intestine and Transport:
   Free amino acids are absorbed through the intestinal villi and transported into the bloodstream, from where they are distributed throughout the body to be used in building body proteins and other metabolic processes.

• Stimulation of Salivary Glands, Taste Buds, and Pancreatic Secretions
  The stimulation of the salivary glands promotes the production of amylases, such as ptyalin, which begins starch digestion in the mouth.
  It also stimulates the taste buds to increase water intake, thus increasing food consumption.
  Finally, the addition of acids promotes an increase in pancreatic secretions to aid the more efficient breakdown of macronutrients and favor absorption.

2.Intestinal Prebiotic Function (Intestinal Acidification)

• • Control of Intestinal Pathogens and Reduction of Digestive Disorders
    By adding organic acids, intestinal acidification plays a crucial role in the digestive health of birds by creating an acidic environment in the intestines. This makes it difficult for pathogenic bacteria like E. coli, Salmonella, and Clostridium to grow, as they are more sensitive to low pH. This helps reduce the risk of intestinal infections and digestive disorders.
    Organic acids, with a higher dissociation constant (pKa), remain in their acidic form for longer in the intestine. This acidic environment not only inhibits harmful bacteria but also promotes the growth of beneficial bacteria, such as Lactobacillus and Bifidobacterium, which are essential for good digestion and nutrient fermentation.
    Additionally, the acidity in the intestine improves nutrient absorption, as some minerals and other compounds are better assimilated at a lower pH. In summary, intestinal acidification not only prevents diseases but also improves nutritional efficiency and overall well-being.

• Strengthens the Intestinal Barrier and Boosts the Immune System
  Pathogen-free and properly acidified water promotes a balanced intestinal microbiome, fostering the growth of beneficial bacteria that have a positive effect on immune function. A healthy intestinal microbiome is key to an efficient immune system, allowing for a better response to infections and other environmental challenges.

Conclusion
Water acidification in poultry farming is a highly effective health and nutritional management strategy. It improves digestion, promotes a healthy intestinal tract, reduces pathogen pressure, and enhances productive performance.

Its regular implementation, as part of an integrated biosecurity and intestinal health program, reduces reliance on antibiotics, favors bird well-being, and improves farm profitability.