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United States Department of Agriculture

Agricultural Research Service

Title: Muscle Fiber Types of Back, Breast and Wing Muscles from Broiler Chickens in Relation to Age and Sex

item Chiang Winnie, - UNIV OF DELAWARE
item Solomon, Morse
item Kotula Kathryn L, - UNIV OF DELAWARE

Submitted to: Journal of Muscle Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 17, 1995
Publication Date: N/A

Interpretive Summary: Broiler (chicken) meat quality is affected by many factors and muscle fiber morphology is one of the factors. Muscle fiber growth and differentiation differs among muscles which are characterized by speed of contraction or energy metabolism. Sex of the chicken under investigation had no influence on either the distribution or size of muscle fibers. Muscle fiber area increased in size as chickens became older; however, the rate of enlargement decreased with increasing chronological age. Fast twitch, anaerobic fibers play an important role in increasing muscle deposition, as reflected by the growth of this fiber type in muscles with high growth rates. Knowing the morphological and compositional characteristics of individual muscles in the carcass will assist in the success of developing value-added meat products.

Technical Abstract: Changes in muscle fiber types in relation to chronological age and sex from selected back, breast and wing muscles of broiler chickens were characterized. Types of muscle fibers were distributed unevenly across the cross sections of back muscles: more red fibers in the deep part than in the superficial part. Very high proportions of aW fibers were found in breast and wing muscles. Muscle fiber area increased as chickens became older; however, the rate of area enlargement decreased with increasing chronological age. The sex of the chickens had no influence on either the proportion of muscle fiber types or areas. However, a sex x age interaction was observed for muscle fiber population in the pectoralis superficialis muscle. Giant fibers were observed and these resembled BR and/or aR fibers. More giant fibers were observed in muscles consisting of higher proportion of aW fibers.

Last Modified: 4/21/2015
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