title: Effect of two thermal regimes on the muscle growth dynamics of sea bass larvae, Dicentrarchus labrax L.
abstract: Muscle growth was studied in larvae of sea bass, Dicentrarchus labrax L., reared at two temperatures: real ambient temperature ( congruent with 15 degrees C during vitelline phase and increased gradually) and 19 degrees 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 degrees 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 degrees 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 degrees 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 degrees C. Metamorphosis finished earlier in fish reared at 19 degrees 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 degrees C (P > 0.05).
authors.affiliation: Anatomía Veterinaria, Fac. Veterinaria, Universidad de Murcia 30100, Spain. mdayala@um.es
authors.forename: M D
authors.initials: MD
authors.lastname: Ayala
authors.forename: O
authors.initials: O
authors.lastname: López Albors
authors.forename: A
authors.initials: A
authors.lastname: García Alcázar
authors.forename: E
authors.initials: E
authors.lastname: Abellán
authors.forename: R
authors.initials: R
authors.lastname: Latorre
authors.forename: J M
authors.initials: JM
authors.lastname: Vázquez
authors.forename: G
authors.initials: G
authors.lastname: Ramírez Zarzosa
authors.forename: F
authors.initials: F
authors.lastname: Martínez
authors.forename: F
authors.initials: F
authors.lastname: Gil
mesh_terms: D000818:Animals; D001492:Bass / Q000254:growth & development / Q000502:physiology*; D001835:Body Weight; D005260:Female; D007814:Larva / Q000254:growth & development / Q000502:physiology; D008297:Male; D008675:Metamorphosis, Biological; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000166:cytology* / Q000254:growth & development; D013696:Temperature