Induction of deep pectoral myopathy in broiler chickens via encouraged wing flapping

Abstract

Deep pectoral myopathy (DPM) is an ischemic necrosis of the pectoralis minor muscles of poultry first described in adult turkeys [1,2], later in adult broiler breeders [3], and finally in young broiler chickens [4]. Extensive investigations and reviews on the etiology and pathophysiology of DPM have been published [5][6][7][8]. Reports of the occurrence of DPM in broilers, especially those marketed at heavy BW for further processing, have occurred more frequently in the past decade than in the previous decade [9][10][11][12]. The pectoralis minor muscles are uniquely susceptible to this type of lesion because they are surrounded by an inelastic membrane (fascia) and located at a site (i.e., between the sternum and pectoralis major muscle), which SUMMARY A reproducible method for inducing deep pectoral myopathy (DPM) in broilers was investigated. To induce DPM, broilers were subjected to encouraged wing flapping (EWF) by repeatedly raising and lowering them a distance of 1 m. Each cycle resulted in 1 bout of 4 to 6 flaps. At 45 d of age, no DPM occurred in control birds subjected to 0 cycles of EWF or those subjected to 5 cycles, whereas the prevalence of DPM (% of pectoralis minor muscles with lesions) was 7 and 33% in those subjected to 10 and 20 cycles of EWF, respectively. The prevalence of DPM in broilers subjected to 25 cycles of EWF at 49 d of age was 56% and was unaffected by sex or a 0.4-kg difference in BW. The involvement of DPM (i.e., % of muscle surface discolored) and the discoloration score (predominant color of lesions) were also unaffected by sex or BW. The prevalence of DPM at 48 or 120 h after EWF averaged 48% and was unaffected by time from EWF. However, involvement of DPM and discoloration increased with time from EWF, reflecting a change in lesion extent or visibility, and color. Susceptibility to EWF-induced DPM was observed at 26 d of age in males and 36 d of age in females. The prevalence of DPM was greater in males at 33 and 36 d, but was similar thereafter and was unaffected by BW. Therefore, the EWF method of DPM induction is useful for accentuating the occurrence of the disease to facilitate further study and that susceptibility to DPM is primarily associated with age above certain thresholds for each sex.

Evaluation of Capillary and Myofiber Density in the Pectoralis Major Muscles of Rapidly Growing, High-Yield Broiler Chickens During Increased Heat Stress

“…Forty-five day-old broiler chickens subjected to 10 or 20 cycles of encouraged wing flapping had deep pectoral myopathy indices of 7% and 33%, respectively (18). Gross lesions were subtle 24 hr after deep pectoral myopathy induction, but progressively increased to severe myonecrosis with significant hemorrhage over a course of 11 days (18). Histologically there is extensive interfasicular edema and early myonecrosis within as little as 3 hr postexertion (Joiner, pers.…”

“…Our research group recently developed an experimental protocol for the induction of deep pectoral myopathy in broiler chickens via encouraged wing flapping (18). Forty-five day-old broiler chickens subjected to 10 or 20 cycles of encouraged wing flapping had deep pectoral myopathy indices of 7% and 33%, respectively (18). Gross lesions were subtle 24 hr after deep pectoral myopathy induction, but progressively increased to severe myonecrosis with significant hemorrhage over a course of 11 days (18).…”

“…Gross lesions can develop within a matter of hours following an acute bout of muscle exertion, irreversibly damaging the pectoralis minor muscles and decreasing breast muscle yield at slaughter (17). Our research group recently developed an experimental protocol for the induction of deep pectoral myopathy in broiler chickens via encouraged wing flapping (18). Forty-five day-old broiler chickens subjected to 10 or 20 cycles of encouraged wing flapping had deep pectoral myopathy indices of 7% and 33%, respectively (18).…”

Köy Koşullarında Beslenen Broylerlerde Saptanan Derin Pektoral Myopatide Patolojik İncelemeler

“…However, there is some disagreement on this matter [12] . The problem is also seen more frequently in free-range broilers [13] .…”

İlave Koenzim Q10 ile Beslenerek Derin Pektoral Myopati Oluşturulan Etlik Piliçlerde Miyopatinin Devrelerinin Belirlenmesi

“…This contributes to the development of more or less pronounced degrees of DPM [7] . In recent studies, methods defined as forced wing flapping [8] and encouraged wing flapping [9] have been used for the induction and examination of DPM in broilers.…”