Researchers at the University of Arkansas are studying calcium availability in poultry feed, and how the results can optimize calcium digestibility.
Calcium is a key component of poultry feed conversion and supports bone density, enzyme activation, muscle contractions and other critical functions.
Ben Parsons, assistant professor of poultry nutrition with the Arkansas Experiment Station, said in a university news release, that recent work has shown that excess calcium can exacerbate disease and pathogen challenges.
Parsons' study looked into a comparison between two calcium availability tests, one being a traditional test and a second newer and faster test, and found both offer reliable results to help optimize calcium digestibility.
"The biggest challenge we have is analytically picking up the calcium content of our samples accurately," he said.
Figuring out the value of calcium needed for poultry is something that could save larger producers millions of dollars.
Parsons said even with a small change, the large-scale producers would see a great financial effect.
"If you have a 1-point performance loss, that equates on a yearly basis to around $20 million to $24 million," he said. "Small things that impair performance could end up costing a lot of money because that little reduction in performance gets amplified."
Too much calcium can also reduce the availability of other nutrients, according to Parsons, like phosphorus, which can worsen disease challenges.
Parsons said the study aims to help determine not just how much calcium is in the feed, but how much is being digested and absorbed by the bird.
Broiler feed is currently formulated to meet a total calcium requirement, which does not take into account differences in calcium availability from sources.
"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," he said.
A 2023 study published in the National Library of Medicine found that calcium is closely related to phosphorus in terms of absorption.
The study referenced how phosphorus is the third-most expensive nutrient in poultry diets and a major contributor to environmental pollution.
This creates a need to develop a digestible calcium system in order to meet the birds' requirements and generate accurate ratios between the two nutrients.
The two methods studied by the university researchers include a faster method measuring calcium digestibility in the small intestine, and the older and more time-consuming method of measuring bioavailability using ash or mineral content of a chicken's leg bone.
Parsons said the bone ash method has been around for decades and is mainly for trace minerals and phosphorus, but the researchers developed an approach to measure calcium.
The newer method involves the collection of partially digested feed and comparing the difference in calcium between it and the feed before digestion.
The newer test can be done in 24 hours to 72 hours, whereas the older test can take weeks for bones to absorb the minerals.
The study found that more rapid digestibility can be used to assess calcium availability in feedstuffs. However, Parsons said the bone test can also be used to confirm results from the digestion test, and eliminate analytical errors.
With the results of the study, Parsons said the long-term goal for poultry nutritionists is to move from total calcium requirements to digestible calcium levels.
The tests are able to help poultry producers screen calcium sources that are causing problems and find sources with a sweet spot of digestibility.
"If you get something that solubilizes rapidly in the (gastrointestinal) tract, that's actually problematic and leads to reduced availability of other nutrients like phosphorus," he said. "If you get it solubilizing too slowly, the bird can't use it."