Acid binding capacity-4: A key parameter in weaned pig diet formulation.

Wednesday, January 17, 2024

By Mohsen Abedin, PHD.

The post-weaning period is a critical and often stressful phase in a young pig's life, drawing significant attention to optimizing the gastrointestinal tract for improved lifetime production and overall health.

Newly weaned piglets experience a substantial shift in their dietary composition, transitioning from a liquid milk, rich in highly digestible nutrients, to a dry, plant-based diet.

The acidic environment in the stomach plays a crucial role in facilitating the digestion and absorption of nutrients from feed. However, the stomach of young piglets has limited acid-producing capacity during this critical period.

The inadequate production of gastric acid in piglets during this phase can have detrimental consequences, resulting in reduced performance and compromised intestinal health.

In Canada, particularly in the eastern regions, it's common for pigs to be weaned between 18 and 21 days of age, at a stage when their gastrointestinal tract is still relatively underdeveloped.

Figure 1 illustrates that the production of hydrochloric acid in a pig's stomach remains limited until the pig reaches seven to eight weeks of age.

In suckling pigs, the primary source of acidification in the stomach is bacterial fermentation of lactose in milk. When piglets transition to solid feed at weaning, there is a notable increase in gastric pH, which can reach levels as high as 5.0 for several days post-weaning. Maintaining a low stomach pH is crucial for effective protein digestion. Also, elevated gastric pH levels create an environment where opportunistic pathogens can grow, potentially compromising the digestive tract and leading to clinical infections, diseases, and, in severe cases, mortality.

From a nutritional perspective, the inadequate acidification of the stomach can often be attributed to the high acid-binding capacity (ABC) of the ingredients in the feed. The ABC concept revolves around the adjustment of stomach acidity by incorporating ingredients with low acid-binding properties.

This ABC value is measured by a standard laboratory test at a pH of 4, denoted as ABC-4. The higher the ABC-4 value, the greater the amount of acid the piglet must secrete to reduce the pH to 4, a critical step for activating digestive enzymes and breaking down proteins into peptides.

At the Trouw Nutrition Research Centre and our validation facilities, we have undertaken eight studies over the past few years, directly or indirectly examining the influence of diet ABC-4 values on nursery performance. A portion of these studies were carried out at our validation sites in Canada under real-world, commercial conditions.

Our latest research, presented at the 2023 Midwest Section Animal Science Meeting, examined the effects of ABC-4 levels in diets with either high zinc or low zinc on the growth performance of nursery pigs. Overall, in these studies, reducing the ABC-4 values of both high zinc and low zinc diets through the use of acidifiers and/or different calcium sources improved the feed efficiency of pigs during the nursery phase.

We are actively engaged in research to evaluate the ABC-4 values of the ingredients and medications used in nursery diets. Furthermore, we are investigating the ideal ABC-4 levels within complex early nursery diets under various zinc levels and health conditions.

As concerns about the use of pharmacological levels of zinc continue to rise, the formulation of a diet featuring a low ABC-4 value holds promise in enhancing gut health and, in turn, the performance of early nursery pigs.

This approach can offer valuable support to producers in the post-weaning phase, especially when they aim to use nutritional levels of zinc. BP