7 September 2021 - Minerals are essential nutrients for livestock. Feedstuffs typically do not contain a sufficient trace mineral concentration, so they are supplemented to the diet, mainly in forms of oxides, sulphates or organic complexes.
In broiler nutrition, the complex interactions between different minerals sources, other ingredients, and the broiler itself, coupled with the relatively low costs of trace mineral products, have led to elevated levels in diets. It is widely viewed that the broiler industry continues to overfeed them.
In addition to the ongoing work by nutritionists to optimise mineral nutrition considering other parameters than solely bird performance, there is also the poultry sector’s focus on sustainability to bear in mind. The awareness is growing that a reduction of mineral levels will lead to more cost-effective broiler feeds and a smaller environmental footprint of broiler production. All these drivers are increasingly prompting a rethink of the way we formulate diets containing minerals.
Providing an update on the topic at the 2021 Arkansas Nutrition Conference last week, Rick Kleyn of Spesfeed Consulting in South Africa, argued that there are considerable opportunities for reducing macro minerals such as calcium and phosphorus, particularly for older birds.
“As growth rates increase and production systems intensify, mineral nutrition will become more critical … Nutritionists will have to meet the increased demands of society, together with the potentially higher nutrient requirements of broilers, while minimising the residual amount of minerals in their manure,” he said.
“Mineral levels need to be reconsidered for one reason alone – sustainability. Remember, there are three legs to sustainability, economic (we must use cheaper feed), environmental (demand for resources and pollution caused by production systems) and lastly welfare. When using elevated mineral levels the birds may suffer – especially wet litter and poor environments,” Kleyn told Feedinfo.
However, the poultry nutrition consultant pointed out that research into trace mineral nutrition lags behind other areas due to the relatively low cost of their inclusion in premixes. These low costs also explain why high levels are often included in broiler diets.
Kleyn said: “Exact requirements of individual trace minerals are difficult to establish (sources, interaction, and variable uptakes). Research has often been carried out with purified diets, on old genetic material and in less intense production systems. The fact that minerals are relatively inexpensive (only use small amounts) has discouraged research into the field, which does not help. As a result, commercial nutritionists tend to be safe rather than sorry and use elevated mineral levels.”
“As an industry we will be obliged to include lower levels of minerals in the diet. Nutritionists are concerned about two things: the cost of any change that is made and the ultimate performance of the birds.”
Bearing in mind that the science is mostly not available, Kleyn suggests a phased approach to the issue.
“Gradually reduce the mineral levels in your diets,” he said. “Begin with Finisher diets, if all goes well, do the same with Grower and Starter diets. Then go back to the Finisher and shave off a bit more.”
He also recommends having the opposite approach when using relatively expensive organic minerals which are shown to enhance broiler performance and carcass quality whilst reducing overall trace mineral inclusion.
“Begin with the Starter as this is when the birds have the highest relative requirement but only eat a small proportion of the total feed consumed. If the introduction of organic products (combined with a reduction of inorganic minerals) into the Starter is successful, then move on to the Grower and Finisher,” he said.
“How long this process will take will depend on individual nutritionists (who are conservative by nature),” he went on to say. “In future, legislation may determine how it should be done.”
The consultant is also of the view that the use of organic mineral sources, with a higher mineral availability and uptake, will reduce the levels of trace minerals used in broiler diets. Additionally, the formulation of diets that target precision nutrition will eventually demand extensive use of alternative mineral sources.
The advent of phytase enzymes, for instance, has given nutritionists more latitude regarding the levels of calcium and phosphorus used in commercial diets and will allow for a reduction of the levels of both minerals.
Furthermore, Kleyn pointed out that at the moment, nutritionists tend to ignore the trace minerals in common ingredients, such as limestone, fishmeal, dicalcium phosphate, monocalcium phosphate, soybean meal, maize or canola meal.
This is a practice “that will need to change”, he said, “particularly in the light of the use of the phytase enzyme.”
“One needs to look at the macro minerals as well,” Kleyn added. “For example, all ingredients contain calcium, but we are only beginning to understand that it is not all available to the bird.”
“In future, we will need to work with available dietary minerals for each ingredient.”
