Calcium tests in poultry offer chance for improved feed efficiency

A percentage point of loss of conversion of food in large -scale poultry production can cause millions of income, so even small improvements – such as a single nutrient adjustment in food – can make a large difference.

Calcium plays a key role in converting poultry food. In addition to bone density, enzymatic activation, muscle contraction and other critical functions, calcium affects the effectiveness of food processing into weight gain. But in flesh chickens, it is not only the amount of calcium that counts. What really matters is bioavailability: what part of this nutrient that the bird can really use.

The measurement of the bioavailability of calcium was precisely delicate for poultry scientists.

“The biggest challenge we have is to take analytically the calcium content of our samples with precision,” said Ben Parsons, assistant professor of poultry nutrition with the agricultural experimentation station of Arkansas, the research branch of the agriculture division of the University of Arkansas and Dale Bullers College of Agricultural, Food and Life Sciences. “Our main sources of calcium – Dicalcium and limestone phosphate – are rocks. You can get a large room or a small one in the sample, and this causes variability.”

A new study of Parsons and its colleagues from the Center of Excellence for Poultry Science compared the results of two calcium availability tests – a classic and faster test approach – and have found that the two tests offer reliable results that can help poultry producers optimize the digestibility of calcium.

Arkansas has always been classified as the third producer of flesh chickens in the country, producing more than 7.4 billion pounds of meat of flesh in 2023, according to the latest agricultural profile of Arkansas. Taking into account $ 6.5 billion, the production of flesh represents approximately 45% of all agricultural receipts in cash in Arkansas.

In the quest for optimal poultry feeding formulation, poultry nutritionists examined not only the amount of calcium in the food, but the digital quantity and absorbed by the bird.

Currently, the flow is formulated to meet a total calcium requirement in the diet, which does not take into account the differences in availability of calcium among sources. Even among the different sources of the same ingredient, the availability of calcium can vary due to factors such as the solubility and size of the particles.

Millions value

Limestone is the most common calcium source in poultry diets, said Parsons. It is inexpensive and widely available, but its digestible calcium content can range from 20% to almost 80%. To be safe, food producers often add more than necessary – but too much calcium can reduce the availability of other nutrients, such as phosphorus, and can even worsen the challenges of the disease, Parsons said.

“Some recent works show that excess calcium can exacerbate the diseases and challenges of pathogens,” he said. “We do not understand how at the moment, but we know that there is value to try to become more precise in the way we meet the animal’s calcium needs.”

The value could be worth millions. As Parsons explained, the food conversion ratio is a numerical value which can have a large effect even when it is a small number due to the high volume of birds cultivated by the largest poultry producers.

“If you have a loss of performance from one point, this is equivalent to an annual base at around 20 million to 24 million dollars,” said Parsons about large -scale poultry farms. “The little things that harm performance could end up costing a lot of money because this small reduction in performance is amplified.”

Two ways to measure the availability of calcium

Parsons and Rebekah Drysdale, Ph.D. Poultry Sciences Student at the Buamers College of the University of Arkansas, has conducted studies showing that a relatively new and rapid method to measure the digestibility of calcium in the intestines in small intestines reflects the results of an older and longer method to measure bioavailability using ashes or mineral content The bone of the leg of a chicken.

DRYSDALE has developed the method to measure the bioavailability of calcium using bone ashes in modern flesh chickens as part of the thesis of its mastery, noted Parsons.

“The method of bone ash is a classic approach that has existed for decades, mainly for traces of minerals and phosphorus, but very recently, we have developed a regression approach for bone ashes to measure calcium,” said Parsons. “Our goal was to compare it to the new method, and if we could show that they are similar, then we could move forward in the use of these tools to assess many different calcium samples.”

The most recent method is called “apparent ileal digestibility test” and implies the collection of partially digested food known as Digesta in the Ileon, which is the end of the small intestines. The difference in calcium that was in the food and what remains after digestion in the dried digesta can then be calculated.

Although the apparent ileal digestibility test can be performed in 24 to 72 hours with as little as a diet, the bone ash test process takes two weeks before nutrients are absorbed in the bone and twice as much diets are necessary compared to the more recent digestibility test.

The study results indicate that the more recent and faster digestibility test can be used to assess the availability of calcium in food. In addition, relative values ​​of bioavailability of calcium based on bone ash content can also be used to predict or estimate the calcium digestibility values.

Parsons said that if the digestibility test is useful for providing direct calcium availability measures, bioavailability of calcium -based bone -ons can be useful to confirm the results of digestibility tests while also eliminating analytical errors. The bioavailability of calcium based on bone ashes will also explain the absorption, transport and use within the body, which provides additional information beyond absorption or digestibility, added Parsons.

Find the “Sweet Spot”

Parsons said that a long -term objective for poultry nutritionists is to pass total calcium needs in poultry foods at digestible calcium levels.

“There is a big challenge because you must really have a good robust data or a database in the availability of calcium of different sources,” said Parsons.

With different levels of calcium digestibility in different limestone sources, Parsons said that the two test methods can help poultry producers on calcium sources that cause problems and find sources with a “SWET spot” digestibility based on solubility rates.

“You want limestone in the middle of this solubility distribution,” said Parsons. “If you get something that solves quickly in the gastrointestinal tract, this is in fact problematic and leads to a reduced availability of other nutrients such as phosphorus. If you do so solvent it too slowly, the bird cannot use it.”

DRYSDALE and PARSONS published the results of their experiences in the journal Poultry Science under the title “Comparison of the relative bioavailability of calcium based on bone ash and the apparent digestibility of ileal CA in chickens of flesh.”