Trace Mineral Nutrition

Monday, May 13, 2024

Optimizing performance and uniformity in grow-finishing pigs.

By Gavin Boerboom, PhD, Program Manager, Trace Minerals, Trouw Nutrition

The grow-finishing period in commercial swine production represents the phase of production with the longest time frame (ranging from 80 to 180 days) and therefore the greatest opportunity to improve pig health and welfare, as they are tightly correlated.

Improving the health and resilience of grow-finishing pigs improves overall efficiency, ensures a more homogenous herd, and lowers the need for antibiotics. As feed intake is also highest in this period of production, any improvement in feed conversion can lead to substantial economic benefits.

Minerals can play a very important role here, given their involvement in inflammatory responses and the anti-bacterial effects they can have. Zinc, for example, is involved in over 300 enzymes and 2,000 transcription factors, and has the greatest impact on growth rate of all micronutrients, making nearly every metabolic pathway zinc-dependent. The animals' requirements for these trace minerals are not static, as they are defined largely by both external as well as internal factors. The animal's age, health status and sex are examples of internal factors, whereas temperature, humidity, disease pressure, and stocking density are examples of external factors. Heat stress, for example, increases the animals' requirements for minerals as there is an increased need for electrolyte balancing and oxidative responses.

To ensure animal requirements for these minerals are met, the animal nutrition industry includes trace minerals as part of a premix that is added to complete feed. The most commonly used trace minerals are inorganic minerals, coming either from a sulphate or oxide form. These are used mainly for economic purposes, as they are cheaper than better-quality minerals. The uncertainty that exists in the bioavailability of these minerals when included in commercial diets is compensated by using a worst-case scenario bioavailability.

What people tend to forget are the other drawbacks this has, as they can increase overall nutrient inefficacy, vitamin stability and phytase activity. This is due to the unstable nature of the inorganic trace minerals, especially sulphates. Sulphate trace minerals are comprised of weak ionic bonds that are more soluble in water (pH 7), increasing the presence of reactive free minerals. These free minerals can then negatively affect other essential nutrients, like vitamins, lipids, and phytate, and hinder the availability of the mineral (Figure 1). The effects of this are strongest with copper, as copper is one of the more reactive minerals in the diet.

Feeding a diet containing a well-mixed inclusion of trace minerals from an improved source can help animals make better use of all nutrients included in the diet (not only the minerals) and allow them to better respond to any stressors they may experience. Examples of these types of mineral sources are organic or hydroxy trace minerals. In the organic trace minerals, the mineral is attached to an organic ligand, providing a more stable bond to the mineral, thereby reducing the likelihood of interaction with other feed ingredients, and ensuring proper availability. The strength of the bond determines the consistency of the availability. The hydroxy type minerals have a similar type of bond as the organic trace minerals, but also have a metal complex present in a crystalline structure, which further reduces the chances of reactivity, especially in neutral pH water. As a result, the in-feed stability of essential nutrients such as vitamins can be improved, as well as the efficacy of phytase, as can be seen on Page 17 in feeds containing vitamin E (Figure 1).

In some recent animal trials, results showed that the use of hydroxy trace minerals can lead to increases in individual animal performance, but also improve overall uniformity of the herd.

A trial comparing hydroxy copper, manganese, and zinc to sulfate mineral sources demonstrated that hydroxy minerals (IntelliBond™) decreased the expression of serum pro-inflammatory cytokines following an acute (LPS injection) immune challenge (Figure 2). This led to a lower impact on performance, leading to a more uniform herd (Figure 3). Altogether, using hydroxy trace minerals ensures that performance is sustained and economic uncertainty is reduced. BP