Researchers examine calcium optimization in poultry feeds to boost cost efficiencies and sustainability

In the quest to formulate optimum-performance poultry feed, poultry nutritionists have been looking at not just how much calcium is in the feed but how much is digested and absorbed by the bird. In broiler chickens, calcium affects the efficiency of turning food into weight gain, in addition to impacting bone density, enzyme activation, muscle contraction, and other critical functions.

And in broilers, bioavailability is particularly important — that is, how much of the nutrient calcium the bird can actually use for weight gain.

Researchers have examined how calcium plays a crucial role in poultry feed conversion.

One percentage point of feed conversion loss in large-scale poultry production can cause significant revenue losses, so even small improvements — such as fine-tuning a single nutrient like calcium in feed — can make a big difference to the poultry industry. 

Accurately measuring calcium bioavailability has been a challenge for poultry scientists. However, scientists from the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, and the Dale Bumpers College of Agricultural, Food and Life Sciences, recently conducted studies that can help poultry producers optimize calcium digestibility.

Assessing calcium availability

They compared the results of two calcium availability tests — a classic approach and a newer, much faster test. They discovered that both tests offer reliable results that can help poultry producers optimize calcium digestibility.

Limestone is the most common calcium source in poultry diets. It is widely available but expensive, and its digestible calcium content can range from 20% to almost 80%. Therefore, it can be common for feed producers to add more than needed. However, this also comes with consequences, as too much calcium can reduce the availability of other nutrients, such as phosphorus, and may even worsen disease challenges.

“Some recent work is showing that excess calcium can exacerbate disease and pathogen challenges. We don’t understand how right now, but we know that there’s value in trying to get more precise in how we’re meeting the animal’s calcium requirement, Dr. Ben Parsons, an assistant professor of poultry nutrition with the Arkansas Agricultural Experiment Station, tells Food Ingredients First.

“If you have a one-point performance loss, that equates on a yearly basis to around US$20 million to US$24 million. Small things that impair performance could end up costing a lot of money because that little reduction in performance gets amplified.”

Researchers say that currently, the feed is formulated to meet the diet’s total calcium requirement, which does not account for differences in calcium availability among sources. Even among different sources of the same ingredient, calcium availability can vary because of solubility and particle size.

“On a commercial scale, developing and fine-tuning research tools to assess calcium availability in feedstuffs will allow nutritionists to more precisely formulate diets to meet the nutrient requirements of the birds, which will reduce feed cost. Further, we can better identify calcium sources that are poorly available or are causing problems in the field and exchange them for more optimal sources.”

“It is well recognized in the industry that there is value in becoming more precise with how we formulate to meet calcium requirements to reduce the excess levels we have in our diets. In the US, most of the focus right now is on identifying and avoiding the poorly available sources and trying to reduce levels in areas with outbreaks of necrotic enteritis.” 

“Any time we can develop tools that are more rapid, cost-effective, and require fewer dietary treatments, that increase the throughput of the number of samples we can evaluate. That is the main advantage of the newer method: it offers a tool to increase the number of samples that are evaluated, which increases the database we have on different calcium samples and factors within the samples that are affecting calcium availability.”

When we asked Dr. Parsons if he expected feed producers to adopt digestible calcium values in place of total calcium requirements when formulating diets, he explained that in some parts of the world, poultry nutritionists are already formulating with digestible Calcium values. 

“I suspect it will take quite some time before the nutritionists in the US adopt this new approach; however, our nutritionists are using these tools to select the calcium source they use in their diets.”