title: The effect of genetic increases in egg production and age and sex on breast muscle development of turkeys.
abstract: Pectoralis major muscle morphology was studied in both sexes of a turkey line (E) selected long-term for increased egg production and its randombred control (RBC1) from 25 d of incubation through 20 wk posthatch. Pectoralis major muscle samples from 10 individuals from each line-sex-age subgroup were obtained in a manner to prevent contraction. The muscle samples were dehydrated, cleared, embedded in paraffin, sectioned, incubated, and rehydrated before staining with hematoxylin and eosin. Representative sections were given a score by 4 individuals based on breast muscle morphology. The scores ranged from 1 (little extracellular matrix and indistinct muscle fibers) to 5 (large extracellular space and distinct muscle fibers). Scores from 2 to 4 were intermediate to these extremes. The pectoralis major muscle morphology scores were highest at 25 d of incubation and declined greatly at 1 wk of age. The scores increased from 1 to 4 wk of age and remained constant through 20 wk of age. Males had higher scores than females. In the current study, there was no significant difference between the E and RBC1 lines. Based on the results of 3 experiments (2 published and the present one) using the E and RBC1 lines, it appears that genetic increases in egg production may be associated with a slight reduction in pectoralis major muscle morphology scores at 16 wk of age.
authors: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA. velleman.1@osu.edu
authors: S G
authors: SG
authors: Velleman
authors: C S
authors: CS
authors: Coy
authors: J W
authors: JW
authors: Anderson
authors: K E
authors: KE
authors: Nestor
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005260:Female; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology / Q000254:growth & development*; D010058:Oviposition / Q000235:genetics* / Q000502:physiology*; D012727:Sex Characteristics; D014422:Turkeys / Q000235:genetics* / Q000502:physiology*