Endurance-exercised growing sheep: I. Post-mortem and histological changes in skeletal muscles

J L Aalhus; M A Price

doi:10.1016/0309-1740(91)90022-I

Endurance-exercised growing sheep: I. Post-mortem and histological changes in skeletal muscles

Meat Sci. 1991;29(1):43-56. doi: 10.1016/0309-1740(91)90022-I.

Authors

J L Aalhus¹, M A Price

Affiliation

¹ Department of Animal Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.

PMID: 22060971
DOI: 10.1016/0309-1740(91)90022-I

Abstract

A study was conducted with Suffolk ram lambs to determine whether chronic endurance exercise would affect post-mortem changes in muscle tissue. Muscle fibre diameters, sarcomere lengths, fibre types, and pH and temperature declines were measured in five skeletal muscles (semimembranosus, SM: vastus lateralis, VL; semitendinosus, ST; psoas major, PM; gastrocnemius, G). The exercise had no significant effect on muscle size or muscle fibre diameter in any of the muscles studied. However, endurance-exercised sheep had significantly shorter sarcomeres in all five muscles than their non-exercised counterparts. The pH decline curves differed among muscles; those having the highest proportion of glycolytic fibres had the slowest rates of pH decline. The increased proportion of slow-twitch fibres in the SM, VL, ST and G associated with the exercise regime had little effect on the post-mortem pH decline. However, the ST also had a significant exercise-associated increase in the proportion of oxidative-glycolytic fibres (intermediate) and was the only muscle in which exercise influenced the rate of pH decline significantly.