Some broiler chickens suffer from wooden breast syndrome, which causes their meat to turn chewy and hard. Birds with this disorder can't be sold, and it can afflict up to half of a flock, causing significant losses. Scientists have now learned that an enzyme that's critical to the metabolism of fat, lipoprotein lipase, may play a role in wooden breast syndrome. The findings have been published in Scientific Reports and may provide insight into human diabetes.
University of Delaware associate professor of animal and food sciences Behnam Abasht led the work, which revealed problems in gene expression when wooden breast syndrome starts. This may indicate that the disease is metabolic, and caused by the abnormal buildup of fat in breast muscle tissue.
"The industry desperately needs a solution right now. Conservative estimates project that wooden breast syndrome is costing the U.S. agricultural community $200 million dollars per year, but this number may be much higher," said Abasht.
Wooden breast syndrome is a worldwide problem and impacts 700 producers and over 1,000 backyard chicken owners in Delaware alone. This research may help growers manage the condition by using supplements or additives. It may also help scientists learn more about human metabolic disorders in which fatty deposits accumulate in the arteries.
In this work, RNA sequencing was used to identify the genes that are expressed in broiler chickens, which grow quickly, and legacy chickens that grow more slowly. The scientists found that lipoprotein lipase expression was higher in chickens with wooden breast syndrome. Chickens usually use sugar for fuel and not fat, yet fat was accumulating in their breast muscles. The scientists also discovered that the lipoprotein lipase gene was active in chicken endothelial cells. Endothelial cells act as a barrier that separates tissue from blood.
Abasht suggested that if fat is used for energy in chicken breast tissue, it might cause damaging free radicals to be released in excessive amounts in muscle. That may trigger the immune system to react.
"We observed that if a particular vein was attacked by immune cells, the same vein typically also expressed higher levels of lipoprotein lipase," explained Abasht.
This work may help reveal biomarkers that can show which chickens are affected before the disease starts to develop.
Another recent study reported by Abasht's team in Genes has found parallels between wooden breast syndrome and the structural changes that human diabetes can cause in the heart. The researchers are interested in whether diabetes treatments may help relieve wooden breast syndrome. If enough similarities are revealed, the chicken may serve as a useful model for the study of diabetes therapeutics.
"Our main focus was to address this problem from an agricultural perspective, but our findings open new horizons for future research that could benefit both agriculture and human health. This is a very interesting prospect for us," said Abasht.
"There's a lot to be gained from basic research of wooden breast, even if the main goal is to mitigate economic losses in the poultry industry," added doctoral student Juniper Lake, who works in the Abasht lab.