147 Practical application of acid-binding capacity-4 formulation strategies to improve nursery pig performance.

Abstract Considering the acid-binding capacity of feed ingredients when formulating nursery diets is a way to improve feed utilization in newly weaned pigs by promoting an acidic environment in the gut. Research has shown that formulating early nursery diets to approximately 200 meq/kg can improve feed efficiency and increase fecal dry matter, especially in the absence of pharmacological levels of Zn from ZnO. Successfully achieving a low acid-binding capacity-4 (ABC-4) value in diets requires careful ingredient selection. Ingredients commonly found in nursery diets, such as ZnO, calcium carbonate, vegetable proteins, and milk-based products, have high ABC-4 values, leading to an increased buffering capacity of the diet. Finding alternative methods to formulate diets without or lowered levels of these ingredients is necessary to reach ABC-4 levels low enough to elicit a positive response in pig performance. Zinc oxide has the highest value of commonly used ingredients; however, its benefits outweigh the risk of a higher ABC-4 level. Research shows increasing levels of ZnO added to low ABC-4 diets improves growth and feed intake. However, the ability to use pharmacological levels of ZnO in the future is unknown, necessitating alternative formulation strategies, such as ABC-4, to maintain post-weaning pig performance. Calcium carbonate is another high ABC-4 ingredient used in diets. Reducing dietary Ca to levels below the pig’s post-weaning requirement by lowering calcium carbonate elicited a positive effect on weight gain and feed efficiency; however, some production systems may not want to lower total diet Ca. Therefore, there is a need for research on alternative ingredients, such as calcium formate, that allow for lower dietary ABC-4 while maintaining adequate Ca levels. Soybean meal also presents challenges as it traditionally makes up a large portion of the diet. Replacing soybean meal with specialty protein sources, specifically fermented soy products, can reduce ABC-4 of the diet and may bring additional benefits such as reduced anti-nutritional factors, leading to improved pig performance. Milk-based products, commonly used to stimulate feed intake in early nursery diets, can be replaced with crystalline lactose to reduce the diet ABC-4 value, but may lead to decreased feed intake. In addition to avoiding high ABC-4 ingredients, adding acidifiers can lower dietary ABC-4. Fumaric and formic acids have been used in research evaluating ABC-4 due to their strong acidification potential. However, caution should be used to avoid reaching levels that negatively impact palatability and feed intake. Future opportunities evaluating acidification through the water may provide additional options for maintaining an acidic environment in the gastrointestinal tract of the newly weaned pig. Considering dietary ABC-4 when formulating newly weaned pig diets is a promising strategy that can optimize pig performance. However, economics and the farm’s production goals should be considered to maximize producer profitability.