title: Wooden Breast Myodegeneration of Pectoralis Major Muscle Over the Growth Period in Broilers.
abstract: Wooden breast (WB) myopathy of broiler chickens is a myodegenerative disease of an unknown etiology and is macroscopically characterized by a hardened consistency of the pectoralis major muscle. Our aim was to describe the development and morphology of WB over the growth period in broilers. Additionally, the effect of restricted dietary selenium on the occurrence of WB was examined by allocating the birds in 2 dietary groups: restricted and conventional level of selenium. The experiment included 240 male broilers that were euthanized at ages of 10, 18, 24, 35, 38, or 42 days and evaluated for WB based on abnormal hardness of the pectoralis major muscle. The severity and the distribution of the lesion and presence of white striping were recorded. The first WB cases were seen at 18 days; 13/47 birds (28%) were affected and the majority exhibited a mild focal lesion. In subsequent age groups the WB prevalence varied between 48% and 73% and the lesion was usually diffuse and markedly firm. White striping often coexisted with WB. Histological evaluation performed on 111 cases revealed a significant association of myodegeneration and lymphocytic vasculitis with WB. Vasculitis and perivascular cell infiltration were restricted to the veins. Restricted dietary selenium did not affect the occurrence of WB ( P = .44). Our results indicate that WB starts focally and spreads to form a diffuse and more severe lesion.
authors: 1 Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland.|2 Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: H-K
authors: HK
authors: Sihvo
authors: 2 Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: J
authors: J
authors: Lindén
authors: 2 Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: N
authors: N
authors: Airas
authors: 1 Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland.
authors: K
authors: K
authors: Immonen
authors: 3 Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland.
authors: J
authors: J
authors: Valaja
authors: 1 Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland.
authors: E
authors: E
authors: Puolanne
mesh_terms: D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000254:growth & development; D018450:Disease Progression; D008297:Male; D009135:Muscular Diseases / Q000178:diet therapy / Q000473:pathology / Q000662:veterinary*; D010369:Pectoralis Muscles / Q000254:growth & development / Q000473:pathology*; D011201:Poultry Diseases / Q000178:diet therapy / Q000473:pathology*; D012643:Selenium / Q000008:administration & dosage; D014657:Vasculitis / Q000473:pathology / Q000662:veterinary
chemical_list: D012643:Selenium
keywords: broiler; chickens; pectoralis major; poultry; skeletal muscle; vasculitis; white striping; wooden breast myodegeneration