Prevalence of breast muscle myopathies (spaghetti meat, woody breast, white striping) and associated risk factors in broiler chickens from Ontario Canada

Abstract

Spaghetti meat (SM), woody breast (WB), and white striping (WS) are myopathies that affect the pectoral muscle of fast-growing broiler chickens. The prevalence and possible risk factors of these myopathies have been reported in other countries, but not yet in Canada. Thus, the objective of this study was to assess the prevalence and risk factors associated with these myopathies in a representative population of Canadian broilers. From May 2019 to March 2020, 250 random breast fillets from each of 37 flocks (total, 9,250) were obtained from two processing plants and assessed for the presence and severity of myopathies. Demographic data (e.g., sex and average live weight), environmental conditions during the grow-out period (e.g., temperature), and husbandry parameters (e.g., vaccination) were collected for each flock. Associations between these factors and the myopathies were tested using logistic regression analyses. The prevalence of SM, severe WB, and mild or moderate WS was 36.3% (95% CI: 35.3–37.3), 11.8% (95% CI: 11.2–12.5), and 96.0% (95% CI: 95.6–96.4), respectively. Most (85.1%) of the fillets showed multiple myopathies. Regression analyses showed that the odds of SM increased with live weight (OR = 1.30, 95% CI 1.01–1.69) and higher environmental temperature during the grow-out period (OR = 1.75, 95% CI 1.31–2.34). The odds of WB increased with live weight (OR = 1.23, 95% CI 1.03–1.47) and when flocks were not vaccinated against coccidia (OR = 1.86, 95% CI 1.51–2.29). This study documents for the first time a high prevalence of myopathies in Ontario broilers, and suggests that these lesions may have a significant economic impact on the Canadian poultry industry. Our results indicate that environmental conditions and husbandry are associated with the development of breast myopathies, in agreement with the current literature. Future studies are needed to determine how risk factors can promote the occurrence of these conditions, in order to implement possible mitigating strategies.

Factors Affecting Breast Myopathies in Broiler Chickens and Quality of Defective Meat: A Meta-Analysis

“…Reports by Lorenzi et al (2014) described a prevalence of 43.1% of WS fillets which reached 60.3% in broilers with higher slaughter weight. More recent reports (Petracci et al, 2019;Che et al, 2022b) showed high WS occurrence (>90%) which could be partly attributed to increased awareness of the issue and invested efforts to monitor and better understand the etiology and mechanisms leading to myopathies occurrence (Soglia et al, 2021).…”

“…As for the other myopathies, relating flock data of growth to individual data of myopathy, Che et al (2022b) recently found that increased live weight is a risk factor for both WB and SM occurrence. Stated the high correlation between slaughter weight and daily weight gain in our data set (R 2 : 0.86; data not reported in tables), this result is consistent with our observations.…”

“…vs 26.8%); Caldas-Cueva et al ( 2021) found an approximately three times higher occurrence of moderate to severe WB myopathy in males compared to females; and Lake et al ( 2021) reported a higher prevalence of WB (87% vs 71%) and WS (87% vs 73%) in males than females. As for SM, the only available data by Che et al (2022b) report an average occurrence of 36.3% on a sample size of 9,250 chickens (average live weight at slaughter: 2.36 kg) collected in two slaughterhouses in Ontario (Canada) from flocks comprising only males, only females, and both sexes, whereas they did not identify sex as a risk factor.…”

“…Previous studies highlighted the importance of understanding the environmental and/or management factors that contribute greater than 65% of the variance in the incidence of WS and more than 90% of the variance of the incidence of WB (Bailey et al, 2015). This was stressed in recent analyses of risk factors for myopathies that collected data from different flocks in two Canadian slaughterhouses (Che et al, 2022b) which identified high environmental temperature during the grow-out period and absence of vaccination against coccidian as risk factors for increased probability of showing SM and WB, respectively. Some studies suggest that there are biological characteristics in male broilers that make them more susceptible to WB (Brothers et al, 2019), while female broilers have a higher predisposition for SM (Pascual et al, 2020b).…”

“…Few studies investigated the correlation between individual growth traits and myopathy occurrence (Bailey et al, 2015;Aguirre et al, 2020;Santos et al, 2021). Also, according to our knowledge, only one study included SM in such analyses using flock data (Che et al, 2022b).…”