[...] Also, the occurrence of severe WS was higher in Ross 308 chickens than in Cobb 500 chickens (25.9% vs 7.41%), and up to 40% of medium and heavy broiler chickens raised under commercial conditions had WS conditions (
Lorenzi et al., 2014).
Feeding a high-energy diet produced birds with higher body weight and accomplished lower feed conversion ratios but increased the incidence of WS breast fillets. Higher levels of lipids and lower amounts of protein in diets also increased the occurrence of WS in broilers (
Kuttappan et al., 2009).
Bauermeister et al. (2009) reported a higher incidence in broilers processed at an older age (8 wks old) than a younger age (6 wks old) because of the higher body weight at older ages. More than half of the broilers are processed at older ages currently (>8 wks), and the meats are deboned and used for portioning and further processing (
Owens, 2018). So, WS in broiler breast fillets could affect the poultry meat market significantly and result in higher economic losses.
The occurrence of WS in broilers was reduced by controlling the growth trajectory through feed reduction during the rearing period (
Meloche et al., 2018b). Restricting feed from 13 to 21 d of age was effective in controlling muscle fiber degeneration, but too early feed restriction (first two-week post-hatching) had adverse effects on the growth of broilers (
Kuttappan et al., 2012a). During the re-alimentation period, however, previously restricted birds showed a compensatory growth and the effects of feed restriction disappeared (
Trocino et al., 2015). The broiler line with high ultimate pH had a higher incidence of moderate and severe WS than the low ultimate pH lines regardless of the sex (
Alnahhas et al., 2016;
Muldahl et al., 2015;
Petracci et al., 2013).
