caa a22 4500 388059699 CHVBK 20180307125117.0 cr unu---uuuuu 161130e199806 xx s 000 0 eng 10.1017/S1357729800009310 doi S1357729800009310 pii (NATIONALLICENCE)cambridge-10.1017/S1357729800009310 Adaptations in muscle fibre characteristics induced by physical activity in pigs [Elektronische Daten] The influence of regular exercise training and physical activity on distribution of muscle fibre types, fibre cross-sectional areas and the number of adjacent capillaries per fibre type and per fibre (capillarization) was studied in five muscles from 48 female and 48 entire male pigs. In the growth interval from 30 to 100 kg, the pigs were subjected to one of three treatments: individual housing in pens of 2·5 m2 (treatment C), individual housing and treadmill training for 15 minlday at a speed of 4 kmlh, 5 days/week for a period of 70 days (treatment T), and housing in large pens (36 m2, 40 pigs per pen) allowing for spontaneous physical activity (treatment F). In m. longissimus dorsi, treatment F increased the ratio of fast-twitch oxidative (FTa-) to fast twitch glycolytic (FTb-) fibres, elevated the mean fibre cross-sectional area and the number of capillaries per fibre. In m. biceps femoris (BF) from female pigs, the only adaptation found was a marked training-induced (treatment T) increase in the cross-sectional area of the slow-twitch (ST-) fibres. In m. semitendinosus and BF from male pigs, treatments T and F increased the ratio of FTa- to FTb-fibres. Both training and spontaneous activity increased the proportion of ST-fibres in m. trapezius thoracis (0·48 in treatment C, 0·53 in T and 0·52 in F). Conversely in m. psoas major, treatment F increased the proportion of FTa-fibres (0·15 in C and 0·19 in F) at the expense of ST- and intermediate FTc-fibres. Spontaneous activity induced ST-fibre hypertrophy in the five muscles. For several muscles, the mean fibre cross-sectional area was significantly higher in female than in male pigs. Copyright © British Society of Animal Science 1998 meat quality nationallicence muscle fibres nationallicence physical activity nationallicence pigs nationallicence Petersen J. S. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark Henckel P. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark Oksbjerg N. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark Sørensen M. T. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark Animal Science Cambridge University Press 66/3(1998-06), 733-740 1357-7298 66:3<733 1998 66 ASC https://doi.org/10.1017/S1357729800009310 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1357729800009310 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petersen J. S. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark NATIONALLICENCE 700 1- Henckel P. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark NATIONALLICENCE 700 1- Oksbjerg N. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark NATIONALLICENCE 700 1- Sørensen M. T. Danish Institute of Agricultural Sciences, PO Box 50, DK-8830 Tjele, Denmark NATIONALLICENCE 773 0- Animal Science Cambridge University Press 66/3(1998-06), 733-740 1357-7298 66:3<733 1998 66 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge