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Organic trace minerals in pig production

A lot has been said about the use of organic trace minerals in pig production - we look at some of the findings around the globe. From the effects on phytase to the environment and meat quality to name a few.

Trace minerals are required elements for the proper growth and development and optimum health and immunity of pigs. Trace minerals, as the name suggests, are needed in minute quantities simply because the dietary requirements are relatively small. However, without even these minuscule quantities of trace minerals in the diet, characteristic deficiency diseases can occur; at the very least, pigs do not grow or reproduce as efficiently without sufficient trace minerals. In modern indoor-housing pig production systems, pigs do not have access to alternative sources of trace minerals, such as soil or forage, which increases the importance of meeting trace mineral requirements through the diet.

There are two major classifications of trace mineral products:

  • Inorganic trace mineral salts; or
  • Organic trace mineral products, so called because they resemble the forms found naturally in feed ingredients. Organic trace minerals are generally more easily absorbed by animals compared to traditional inorganic mineral salts (e.g. sulphates, oxides), which can allow for lower dietary inclusions of organic trace minerals.

Over the last ten to 15 years, the availability of organic trace mineral products in the marketplace has increased and, correspondingly, so has the availability and breadth of information.

Heavy metals in trace mineral sources

In the current marketplace, there is a plethora of trace mineral sources for further manufacture in complete diets for pigs and other species. However, the choice of trace mineral source should not be taken without regard to the known and unknown components that may be present in the product. In 2015, Alltech’s laboratory collected samples and analysed for arsenic, cadmium and lead. The results of this heavy metal survey revealed that 14% of the inorganic trace mineral sources and 7% of the organic trace mineral sources tested contained levels of contamination greater than EU allowable limits. Heavy metal contamination can not only impact animal performance, but may have severe implications in consumer safety.

Trace minerals are typically added to diets as components of a premix, which helps to ensure equal distribution throughout the final diet. However, premix components can react with each other, reducing availability of individual nutrients, especially vitamins. Because premixes are composed of typically expensive ingredients, improvements in the stability of the components have economic importance. Premix manufacturers may add ingredients at levels greater than the requirements in an attempt to counteract reductions in nutrient availability due to mixing and storage. Ongoing research has demonstrated that premixes containing inorganic trace minerals are much more susceptible to vitamin degradation and this can happen after stabilisation, relatively quickly – within ten days. After three weeks, the inorganic premix had lost 25% of the initial vitamin E activity.

Similarly, researchers at the University of Minnesota, USA, observed that inorganic trace minerals significantly increased the activity losses of vitamin A, vitamin K, vitamin B12, thiamine mononitrate, folic acid, pyridoxine and choline chloride compared to premixes composited with organic trace minerals. Fewer degradation interactions between components of a premix may provide for lower inclusions of the expensive ingredients while still providing for the nutritional needs of the animals in the final diet.

Trace minerals and phytase

A vast majority of pig diets now include exogenous phytase to improve phosphorus utilisation and reduce phosphorus pollution. However, there are potential negative interactions between trace minerals and phytase, thus reducing the efficacy of phosphorus uplift. Therefore, the Alltech European research group in Ireland investigated the effect of mixtures of inorganic and organic trace mineral sources on phytase activity. The organic trace mineral proteinates tested were significantly less inhibitory of the phytase activity compared to the inorganic trace minerals. Therefore, the choice of trace mineral source can have important implications on the complete diet formulation.

Including organic trace minerals at lower levels in the diet can provide an immediate two-fold benefit:

  • More of the mineral is retained by the animal and available for metabolic functions, increasing efficiency; and
  • Reductions in the environmental impact of production systems are realised due to reduced trace mineral excretion.

A wean-to-finish pig study was conducted in Belgium comparing wheat-soybean meal diets supplemented with either inorganic trace minerals or lower levels of organic trace mineral proteinates. The pigs in this study demonstrated significantly higher average daily gain (ADG), resulting in two kilogrammes of extra carcass weight, higher slaughter efficiency and greater ham width. The resulting economic impact of total replacement of inorganics with organic trace minerals was due to improved performance and reduced mineral inclusion.

Replacement with organic trace minerals

The complete replacement of inorganic trace minerals with organic trace minerals is not only possible, but, in fact, often beneficial to the efficiency of production.

Researchers at the Ohio State University, USA, have investigated the complete replacement of inorganic trace minerals by organic trace mineral proteinates in sows in multiple trials. In measurements of productivity, they have observed that sows fed organic trace minerals from weaning, through gilt development and over multiple parities, resulted in an extra pig per litter compared to similar levels of inorganic trace mineral supplementation. In general, the researchers did not observe significant differences between the sows fed inorganic or organic trace minerals in feed intake, feed efficiency or growth of the offspring.

Organic trace minerals and meat quality

Recent trials at the University of Kentucky, USA have compared pigs fed organic trace mineral proteinates versus pigs fed diets with inorganic trace minerals, mostly in the sulphate form. Pork loins cut into 2.54 cm chops from organic trace mineral fed pigs had improved water-holding capacity and tenderness during refrigerated storage when compared to pigs fed inorganic trace minerals. The improved eating quality in the pork meat may be attributed to greater antioxidant enzyme status, which was shown in a research trial conducted at Murdoch University, Western Australia. In fact, differential effects of organic trace minerals have been observed in measurements of gene expression changes that improve muscle physiology and the conversion to meat. Some of these include:

  • Activation of nuclear factors that provide protection of the muscle against oxidative stress by the activation of antioxidant enzymes;
  • Activation of growth factors that control the differentiation of the vascular system necessary for muscle growth;
  • Inhibition of signalling related to the formation drip channels.

The environment & immune function

Historically, there has been little concern regarding the trace mineral levels run off from swine operations. However, the situation has and continues to change as more countries implement regulations that limit the trace mineral excretion levels. Directly a reflection of the diets being fed to the animals on the farm, manure levels can be manipulated by level and form. A recent study in China using organic trace mineral proteinates observed that pigs had reduced levels of zinc (Zn) and copper (Cu) excretion in waste matter.

Trace minerals, especially Zn, are known to play important roles in the proper functioning of the immune system. Adequate trace mineral tissue levels may support an adequate immune response to a disease-causing agent, minimising the risk of significant economic losses. Regulations and consumer preferences related to antibiotic use will further the need to improve overall animal health and immunity of pigs.

Supplementing organic trace minerals

Many studies have found that there are important benefits from the supplementation of organic trace minerals in total replacement of inorganic trace minerals. Reduced negative interactions can increase bioavailability and reduce the inclusion levels of trace minerals in premixes and therefore help to reduce the concentrations in the manure from the swine industry. Furthermore, organic trace minerals have been shown to have fewer degradation effects in premixes and provide production advantages in the animals.

Alltech’s Bioplex trace minerals include a range of organic trace mineral proteinates – essential trace elements in forms similar to those found in plant (and animal) tissues. The range consists of organic zinc, copper, manganese, iron and cobalt.

Ryan Samuel, research project manager, Alltech

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