A practical way to address woody breast in broilers - Interpretive Summary

      

According to a new study in The Journal of Applied Poultry Research, producers have little to worry about when it comes to branched-chain amino acid interactions and their effects on broiler live performance or carcass traits.

The new investigation suggests that while dietary crude protein levels have increased the amount of these amino acids in feed, the negative effects, which include a rare muscle defect called woody breast, can be easily mitigated.

“Within the confines of tested levels, dietary valine and isoleucine can be lowered without significantly influencing live performance and carcass traits,” write study authors Maynard et al.

The new study was a collaboration between scientists at the University of Arkansas, CJ America-Bio and Cobb-Vantress, Inc.

Branched-chain amino acids (BCAA) are amino acid molecules with an unusual structure. BCAAs have a side chain and a branch made up of a central carbon atom bound with three or more carbon atoms. BCAAs play a role in fatty acid oxidation, immune function and brain function.

While BCAAs are an essential part of human diets, there is some evidence that overconsumption of BCAAs, particularly leucine, may be tied to neurological disorders, obesity and other health issues.

Until recently, BCAA interactions were not a major concern in poultry diets because of their low levels in broiler feeds, and previous research showed no negative effects of amino acid antagonism in broilers. But recent increases in dietary crude protein levels for broilers has made BCAA interactions a new concern for poultry nutritionists.

For the new study, the researchers tested BCAA interactions during two stages of poultry growth. They examined valine and leucine interactions during a 32 to 45 day finisher period, and they evaluated valine and isoleucine interactions during a 39 to 52 day withdrawal period.

The researchers found that branched-chain antagonism between valine and leucine and valine and isoleucine are not likely to be a problem in latter growout phases in poultry production. They report that the absence of significant interactions between these branched-chain amino acids could be linked to reduced branched-chain amino acid requirements for older broilers—and lower inherent leucine levels in lower protein finisher and withdrawal-type diets.

They did observe a small increase in woody breast in broilers given more valine and leucine. Going forward, they plan to take a closer look at how these amino acids affect this muscle growth issue.

      

While woody breast is rare, there is evidence that valine and leucine interactions in high protein feed could increase the frequency.

Poultry scientists have found that adjusting these amino acids levels down just slightly may reduce woody breast with no negative effects on broiler performance.

The full paper, titled “Interactions of the branched-chain amino acids. 2. Practical adjustments in valine and isoleucine,” can be found in the Journal of Applied Poultry Research and online here.

DOI: 10.1016/j.japr.2022.100241