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This Article Full Text (PDF) All Versions of this Article: jas.2008-1286v1 87/2/544    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gondret, F. Articles by Combes, S. Search for Related Content PubMed PubMed Citation Articles by Gondret, F. Articles by Combes, S.

Skeletal muscle adaptations and biomechanical properties of tendons in response to jump exercise in rabbits

F. Gondret^*, P. Hernandez, H. Rémignon and S. Combes

^* INRA, UMR 1079 Systèmes d’Elevage Nutrition Animale et Humaine (SENAH), 35590 Saint Gilles, France , Institute for Animal Science and Technology, Polytechnic University of Valence, P.O. Box 22012, 46022 Valencia, Spain INRA, Université de Toulouse, UMR 1289, Tissus Animaux, Nutrition, Digestion, Ecosystème et Métabolisme (TANDEM), Chemin de Borde-Rouge, Auzeville, BP 52627, 31326 Castanet-Tolosan Cedex; INPT-ENSAT, 31326 Castanet-Tolosan Cedex; ENVT, 31076 Toulouse Cedex 3, France

Florence.Gondret{at}rennes.inra.fr

Abstract

Pen housing has been proposed in rabbits as an alternative to standard-sized cages. Rabbits reared in pens show greater physical activities. This study investigated whether jump exercise could modify body composition, muscle biochemical and histological characteristics, and some meat quality traits, including biomechanical properties of tendons. Male weaned rabbits of similar BW (793 g + 11 g) were either reared in giant collective cages and had to jump over obstacles to get food and water during 35 consecutive days (EXE), or confined in small isolated cages (SED). Rabbits were weighed weekly to determine ADG (n = 79 EXE, n = 46 SED) and ADFI (n = 9 cages in EXE, n = 46 cages in SED). At approximately 10 wk of age, rabbits were slaughtered in 2 series. After an overnight chilling, carcasses in the first series (n = 30 EXE; n = 27 SED) were divided into fore-, intermediate-, and hind-parts. Color and ultimate pH were recorded in biceps femoris (BF) and LM. Achilles tendon and patellar ligament were dissected from the legs and cooked. Muscles [semimembranosus proprius (SMP), semimembranosus accessorius (SMA), and BF] were harvested from the legs in a subset of animals of the second series (n = 10 in EXE, n = 9 in SED). Both ADG and ADFI were slightly reduced (P < 0.10) in EXE rabbits compared to SED rabbits. Exercised rabbits showed a greater (P = 0.01) proportion of hind parts than SED rabbits. Enzyme activities of 3-hydroxyacyl-CoA dehydrogenase and citrate synthase (CS), which play key roles in fatty acid oxidation and terminal oxidative degradation of nutrients, respectively, were increased in SMP, SMA (except CS), and BF muscles of EXE rabbits compared with SED rabbits. Only SMA exhibited a lower (P = 0.05) activity of the glycolytic enzyme, lactate dehydrogenase, in EXE rabbits compared to SED animals. Total lipid content, mean diameter of perimysial adipocytes, and activities of core lipogenic enzymes in SMA and BF muscles did not differ between EXE and SED rabbits. Meat color in BF was shifted towards greater a* (P = 0.001) and b* (P = 0.02) values in EXE rabbits compared with SED rabbits. Cooked Achilles tendon and patellar ligament in the legs had a greater stiffness (P 0.05) in EXE rabbits when compared to SED rabbits. This experiment demonstrates that rabbit muscles turn to a more oxidative metabolic pattern in response to jump exercise. The quality of attachment of cooked meat to bone is also improved in active rabbits.

Key Words: fiber type composition • intramuscular lipids • jump exercise • meat quality • oxidative enzymes • tendons