The Company of Biologists

Table 2.

Mean values (± s.e.m.) forU_crit, and morphometry and enzyme activity of red and white muscles in adult brown trout

	Winter 5°C	Winter 15°C	Summer 5°C	Summer 15°C
U_crit (body lengths s^-1)	1.95±0.07^a	1.33±0.07^b	1.47±0.06^b	2.10±0.12^a
Muscle mass (g)
Red muscle	11.80±0.48	8.42±0.31^a	9.98±0.30	8.29±0.48^a
White muscle	211.99±9.68^a	234.74±13.21^a	249.22±17.88^a	229.09±19.45^a
Heart	0.63±0.02	0.47±0.03	0.55±0.01	0.39±0.01
Mean fibre cross-sectional area (μm²)
Red muscle	1414±78	1040±33^a	1192±69	1056±41^a
White muscle	4442±275^a,b	4463±119^a	4201±147^a	4793±76^b
Capillary density (capillaries mm^-2)
Red muscle	1512±59	1771±60^a	2072±55	1795±30^a
White muscle	230±8^a	208±10^b	222±17^a,b	231±19^a
Capillary-to-fibre ratio
Red muscle	2.36±0.06^a	2.09±0.07	2.32±0.03^a	1.96±0.04
White muscle	2.05±0.05	1.88±0.10^a	1.83±0.05^a	1.72±0.12^a
CS activity (μmol min^-1 g^-1 wet mass)
Red muscle	22.35±2.00	15.13±0.82	17.32±0.81	13.55±0.68
White muscle	4.12±0.11	2.71±0.32^a,b	3.02±0.28^a	2.26±0.15^b
PFK activity (μmol min^-1 g^-1 wet mass)
Red muscle	4.01±0.48^a	3.71±0.28^a	4.25±0.44^a	7.23±0.61
White muscle	21.85±2.50^a	20.74±2.43^a	22.28±3.01^a	35.52±3.45

	Winter 5°C	Winter 15°C	Summer 5°C	Summer 15°C
U_crit (body lengths s^-1)	1.95±0.07^a	1.33±0.07^b	1.47±0.06^b	2.10±0.12^a
Muscle mass (g)
Red muscle	11.80±0.48	8.42±0.31^a	9.98±0.30	8.29±0.48^a
White muscle	211.99±9.68^a	234.74±13.21^a	249.22±17.88^a	229.09±19.45^a
Heart	0.63±0.02	0.47±0.03	0.55±0.01	0.39±0.01
Mean fibre cross-sectional area (μm²)
Red muscle	1414±78	1040±33^a	1192±69	1056±41^a
White muscle	4442±275^a,b	4463±119^a	4201±147^a	4793±76^b
Capillary density (capillaries mm^-2)
Red muscle	1512±59	1771±60^a	2072±55	1795±30^a
White muscle	230±8^a	208±10^b	222±17^a,b	231±19^a
Capillary-to-fibre ratio
Red muscle	2.36±0.06^a	2.09±0.07	2.32±0.03^a	1.96±0.04
White muscle	2.05±0.05	1.88±0.10^a	1.83±0.05^a	1.72±0.12^a
CS activity (μmol min^-1 g^-1 wet mass)
Red muscle	22.35±2.00	15.13±0.82	17.32±0.81	13.55±0.68
White muscle	4.12±0.11	2.71±0.32^a,b	3.02±0.28^a	2.26±0.15^b
PFK activity (μmol min^-1 g^-1 wet mass)
Red muscle	4.01±0.48^a	3.71±0.28^a	4.25±0.44^a	7.23±0.61
White muscle	21.85±2.50^a	20.74±2.43^a	22.28±3.01^a	35.52±3.45

Values with same letters are not significantly different from one another(P<0.05; N=12).