Blackwell Publishing Journal Backfiles 1879-2005
Muscle growth was studied in larvae of sea bass, Dicentrarchus labrax L., reared at two temperatures: real ambient temperature (≅15°C during vitelline phase and increased gradually) and 19°C from fertilization until the end of larval development. Muscle cellularity, body length and body weight were measured.Early temperature influenced larval development and so, pre-larval phase finished earlier at 19°C than at ambient temperature (4 and 6 days, respectively). Temperature also affected muscle growth such that at hatching and at mouth opening hypertrophy of muscle fibres was greater at 19°C (P 〈 0.05), whereas hyperplasia was similar in both groups. After 25 days, the cross-sectional area of the white muscle was greater at 19°C (P 〈 0.05), which was mainly associated with a higher proliferation of new white muscle fibres. At this stage the body length was also higher at 19°C. Metamorphosis finished earlier in fish reared at 19°C (52 days) than at natural temperature (82 days). At this developmental stage body length and cross-sectional area of the myotome were similar in both groups. However, muscle cellularity differed between groups. Thus, hypertrophy of muscle fibres was higher in fish reared at ambient temperature (P 〈 0.05), whereas proliferation of new muscle fibres was higher at 19°C (P 〉 0.05).
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