ABC-4
At weaning, pigs have limited ability to produce enough hydrochloric acid in the stomach to maintain an acidic environment. As a result, early nursery pigs can experience a high gastric pH which can lead to decreased protein digestion and increased opportunity for pathogens to compromise the digestive tract.
Poor acidification of the stomach can be attributed to the high acid-binding capacity of feed ingredients. Acid-binding capacity-4 (ABC-4) is the amount of acid required to lower an ingredient to a pH of 4. The use of low acid-binding ingredients (avoidance of high acid-binding ingredients) in diets of newly weaned pigs could be utilized to maintain an acidic environment in the stomach.