Glucolipotoxicity: A Proposed Etiology for Wooden Breast and Related Myopathies in Commercial Broiler Chickens

Abstract

Wooden breast is one of several myopathies of fast-growing commercial broilers that has emerged as a consequence of intensive selection practices in the poultry breeding industry. Despite the substantial economic burden presented to broiler producers worldwide by wooden breast and related muscle disorders such as white striping, the genetic and etiological underpinnings of these diseases are still poorly understood. Here we propose a new hypothesis on the primary causes of wooden breast that implicates dysregulation of lipid and glucose metabolism. Our hypothesis addresses recent findings that have suggested etiologic similarities between wooden breast and type 2 diabetes despite their phenotypic disparities. Unlike in mammals, dysregulation of lipid and glucose metabolism is not accompanied by an increase in plasma glucose levels but generates a unique skeletal muscle phenotype, i.e., wooden breast, in chickens. We hypothesize that these phenotypic disparities result from a major difference in skeletal muscle glucose transport between birds and mammals, and that the wooden breast phenotype most closely resembles complications of diabetes in smooth and cardiac muscle of mammals. Additional basic research on wooden breast and related muscle disorders in commercial broiler chickens is necessary and can be informative for poultry breeding and production as well as for human health and disease. To inform future studies, this paper reviews the current biological knowledge of wooden breast, outlines the major steps in its proposed pathogenesis, and examines how selection for production traits may have contributed to its prevalence.

Blood Gas Disturbances and Disproportionate Body Weight Distribution in Broilers With Wooden Breast

“…Without discounting the potential contribution of pectoralis major growth rate to WB development, it is important to consider alternative interpretations of these results. For example, it has been proposed that muscle hypertrophy may be symptomatic of WB rather than causal, similar to the pathological hypertrophy of organs in chronic complications of diabetes mellitus in mammals (Lake et al, 2019;Lake and Abasht, 2020).…”

The Potential of Guanidino Acetic Acid to Reduce the Occurrence and Severity of Broiler Muscle Myopathies

“…In these studies, GAA supplementation improved the activity of antioxidant enzymes, such as superoxide dismutase and glutathione peroxidase, measured in serum and liver and decreased plasma levels of malondialdehyde. The antioxidant response should be preserved under stress conditions to minimize susceptibility to myopathy development (Lake and Abasht, 2020).…”

“…The specific origin of these myopathies has not been well elucidated. Recent findings have linked their onset with hypoxia (Malila et al, 2019) due to reduced vascularization (Sihvo et al, 2018), phlebitis (Papah et al, 2017;Chen et al, 2019), and glucolipotoxicity (Mutryn et al, 2015;Abasht et al, 2016;Lake and Abasht, 2020). The final result is a muscle with defective energy-generating pathways combined with a deficiency and/or dysfunction of tissue ATPases, having consequences in myodegeneration and on muscle fiber contraction degree (Baldi et al, 2020).…”

The Role of Incubation Conditions in the Onset of Avian Myopathies

“…The histological (Velleman et al, 2017;Sihvo et al, 2018), metabolic characteristics (Abasht et al, 2016), the gene expression (Mutryn et al, 2015), and the chronological evolution (Chen et al, 2019) of the lesions in the muscles with wooden breast in chickens are very similar to those observed in the muscles of human and diabetic animals (D'Souza et al, 2013). Chronic low-grade inflammation, oxidative stress, lower vascularization, and impaired extracellular matrix remodeling are common denominators for mechanisms underlying deterioration of chicken muscle health and decreased satellite cell functionality similar to the observed in diabetes mellitus type 2 (Lake and Abasht, 2020). These failures in avian muscle development are likely due to disturbances in glucose metabolism, or insulin resistance.…”

“…The beneficial effects of IGF-I lowering glucose via inhibition of renal gluconeogenesis (Clemmons, 2007) and sensitizing cells for insulin (Kabir et al, 2010) can aid in glucose metabolism regulation. Low IGF-I, hyperglycemia, and failures of glucose metabolism are frequently observed in myopathies like striated and wooden breast muscle (Abasht et al, 2016;Lake and Abasht, 2020).…”