Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits

This study was designed to investigate the effects of the interaction among genetic group, sex and age on the frequencies and cross-sectional areas of myofiber types in rabbits. A total of 48 straightbred and crossbred Botucatu rabbits, males and females, were involved in a split plot design with a...

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Main Authors: E. Bianospino, A.S.A.M.T. Moura, F.S. Wechsler, S. Fernandes, M. Dal-Pai-Silva
Format: Article
Language:English
Published: Elsevier 2008-01-01
Series:Animal
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1751731108002759
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author E. Bianospino
A.S.A.M.T. Moura
F.S. Wechsler
S. Fernandes
M. Dal-Pai-Silva
author_facet E. Bianospino
A.S.A.M.T. Moura
F.S. Wechsler
S. Fernandes
M. Dal-Pai-Silva
author_sort E. Bianospino
collection DOAJ
description This study was designed to investigate the effects of the interaction among genetic group, sex and age on the frequencies and cross-sectional areas of myofiber types in rabbits. A total of 48 straightbred and crossbred Botucatu rabbits, males and females, were involved in a split plot design with a 2 × 2 (genetic groups × genders) factorial arrangement. Young rabbits were weaned at 35 days of age and sequentially slaughtered, four per genetic group × sex combination, at 42, 63 and 84 days of age. The flexor carpi radialis muscle was dissected, histological sections (10 μm) were obtained and the frequencies and cross-sectional areas of myofiber types: I, IIA and IIB/X were determined. An effect of the genetic group × sex × slaughter age interaction was found on the frequency distribution of myofiber types. A transition from type IIA to type IIB/X fibers was observed (P < 0.01) with advancing age, except in crossbred females, but the frequency of IIA fibers was already lower (57.3%) and of IIB/X fibers numerically higher (33.7%) in this group at 42 days. The proportions of IIA fibers in straightbred males, crossbred males and straightbred females decreased from 80.1%, 89.4% and 68.8% at 42 days to 43.9%, 52.3% and 40.1% at 63 days, respectively, whereas the proportions of type IIB/X fibers, in the same groups, increased from 10.3%, 1.6% and 22.3% at 42 days to 42.2%, 37.0% and 49.8% at 63 days, respectively. In all three age points, type IIA fibers showed the largest cross-sectional areas, followed by type I and IIB/X fibers. The cross-sectional areas of IIB/X fibers were larger in crossbreds, but no differences were found between genetic groups concerning fiber types IIA and I. All three types of fibers showed positive linear association with age, but relative to the initial area type IIB/X fibers presented a higher degree of hypertrophy (144% up to 84 days) than type IIA and I fibers (86% and 85%, respectively). The flexor carpi radialis muscle was, on average, heavier in crossbred than in straightbred females, but no difference was observed between crossbred and straightbred males. Differences in the weight of flexor carpi radialis muscle were attributed to the hypertrophy of type IIB/X fibers in the crossbreds.
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spelling doaj.art-e877110be86c430295c3cc3c5f8a73342022-12-21T22:04:36ZengElsevierAnimal1751-73112008-01-0121116271632Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbitsE. Bianospino0A.S.A.M.T. Moura1F.S. Wechsler2S. Fernandes3M. Dal-Pai-Silva4Departamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University (UNESP), 18618-000, Botucatu-SP, BrazilDepartamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University (UNESP), 18618-000, Botucatu-SP, BrazilDepartamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University (UNESP), 18618-000, Botucatu-SP, BrazilDepartamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University (UNESP), 18618-000, Botucatu-SP, BrazilDepartamento de Morfologia, Instituto de Biociências, São Paulo State University (UNESP), 18618-000, Botucatu-SP, BrazilThis study was designed to investigate the effects of the interaction among genetic group, sex and age on the frequencies and cross-sectional areas of myofiber types in rabbits. A total of 48 straightbred and crossbred Botucatu rabbits, males and females, were involved in a split plot design with a 2 × 2 (genetic groups × genders) factorial arrangement. Young rabbits were weaned at 35 days of age and sequentially slaughtered, four per genetic group × sex combination, at 42, 63 and 84 days of age. The flexor carpi radialis muscle was dissected, histological sections (10 μm) were obtained and the frequencies and cross-sectional areas of myofiber types: I, IIA and IIB/X were determined. An effect of the genetic group × sex × slaughter age interaction was found on the frequency distribution of myofiber types. A transition from type IIA to type IIB/X fibers was observed (P < 0.01) with advancing age, except in crossbred females, but the frequency of IIA fibers was already lower (57.3%) and of IIB/X fibers numerically higher (33.7%) in this group at 42 days. The proportions of IIA fibers in straightbred males, crossbred males and straightbred females decreased from 80.1%, 89.4% and 68.8% at 42 days to 43.9%, 52.3% and 40.1% at 63 days, respectively, whereas the proportions of type IIB/X fibers, in the same groups, increased from 10.3%, 1.6% and 22.3% at 42 days to 42.2%, 37.0% and 49.8% at 63 days, respectively. In all three age points, type IIA fibers showed the largest cross-sectional areas, followed by type I and IIB/X fibers. The cross-sectional areas of IIB/X fibers were larger in crossbreds, but no differences were found between genetic groups concerning fiber types IIA and I. All three types of fibers showed positive linear association with age, but relative to the initial area type IIB/X fibers presented a higher degree of hypertrophy (144% up to 84 days) than type IIA and I fibers (86% and 85%, respectively). The flexor carpi radialis muscle was, on average, heavier in crossbred than in straightbred females, but no difference was observed between crossbred and straightbred males. Differences in the weight of flexor carpi radialis muscle were attributed to the hypertrophy of type IIB/X fibers in the crossbreds.http://www.sciencedirect.com/science/article/pii/S1751731108002759m. flexor carpi radialisgrowthmyofiberrabbitskeletal muscle
spellingShingle E. Bianospino
A.S.A.M.T. Moura
F.S. Wechsler
S. Fernandes
M. Dal-Pai-Silva
Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
Animal
m. flexor carpi radialis
growth
myofiber
rabbit
skeletal muscle
title Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
title_full Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
title_fullStr Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
title_full_unstemmed Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
title_short Age-related changes in muscle fiber type frequencies and cross-sectional areas in straightbred and crossbred rabbits
title_sort age related changes in muscle fiber type frequencies and cross sectional areas in straightbred and crossbred rabbits
topic m. flexor carpi radialis
growth
myofiber
rabbit
skeletal muscle
url http://www.sciencedirect.com/science/article/pii/S1751731108002759
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AT asamtmoura agerelatedchangesinmusclefibertypefrequenciesandcrosssectionalareasinstraightbredandcrossbredrabbits
AT fswechsler agerelatedchangesinmusclefibertypefrequenciesandcrosssectionalareasinstraightbredandcrossbredrabbits
AT sfernandes agerelatedchangesinmusclefibertypefrequenciesandcrosssectionalareasinstraightbredandcrossbredrabbits
AT mdalpaisilva agerelatedchangesinmusclefibertypefrequenciesandcrosssectionalareasinstraightbredandcrossbredrabbits