Early thermal history significantly affects the seasonal hyperplastic process occurring in the myotomal white muscle of Dicentrarchus labrax juveniles

Abstract

The effect of early (embryonic and larval) thermal history on subsequent (juvenile) white muscle hyperplasia was studied in a teleost fish, the European sea bass (Dicentrarchus labrax L.). D. labrax, incubated and reared at constant temperatures of 13 degrees C, 15 degrees C or 20 degrees C from the embryonic stage of half epiboly up to 18-19 mm in total length, were transferred to ambient seawater temperature and reared for the subsequent 14 months on commercial feed. The somatic growth of juveniles was linked to annual variations of ambient seawater temperature and inversely related to early rearing temperature, so that, after 14 months, the juveniles originally reared at low temperatures had compensated for the growth retardation experienced during early life. The white muscle growth process of juveniles was quantified after two periods of growth opportunity at ambient seawater temperature (100 and 400 days post-transfer) as well as, in order to follow total-length-dependent effects of early temperature and to discriminate total-length-independent effects of early temperature, on juveniles from the three batches sampled at six successive equivalent total lengths (31-33, 84-88, 141-145, 166-172, 196-206 and 211-220 mm). Our data demonstrate the existence of a seasonal recruitment of new white muscle fibres when seawater temperature increases and of a shrinkage of the largest white muscle fibres during the winter months. The seasonal recruitment of new white muscle fibres occurring in juveniles is linked to their early rearing temperature. Juveniles originating from low temperatures have a higher and longer capacity to recruit new white muscle fibres when seawater temperature increases, supporting their better somatic growth. This finding is discussed in relation to the early (embryonic and larval) myogenic processes of the three populations and is related to their sex ratio.

Muscle differentiation in blackspot seabream (Pagellus bogaraveo, Brunnich): Histochemical and immunohistochemical study of the fibre types

“…The intensity of the mosaic hyperplastic process gradually wanes in older fish, although in some fish it may also be seasonal (Carpenè and Veggetti, 1981;Alami-Durante et al, 2007). The very interesting study by Alami-Durante et al (2007) also shows that juvenile hyperplastic muscle growth is affected by earlier thermal life history, an effect presumably operating at the level of the myogenic cell population(s), which is the substrate for the mosaic growth phase.…”

Molecular regulation of muscle development and growth in Senegalese sole larvae exposed to temperature fluctuations

“…Moreover, juveniles from the 15 ºC treatment had the same weight as the 18 ºC ones. It could be hypothesized that the 18 ºC fish would have a lower growth, since fibre hyperplasia is a mechanism that has been positively correlated with larger body sizes (Alami-Durante et al, 2007;Valente et al, 1999).…”

Transcriptomic Characterization of the Larval Stage in Gilthead Seabream (Sparus aurata) by 454 Pyrosequencing

“…Many key developmental events occur during the onset of feeding and the subsequent growing phase of actively eating larvae, making this period the most sensitive to rearing procedures. Morphological and physiological processes such as skeletal development and calcification, the differentiation and proliferation of new fibres in the myotomal musculature, achievement of complete structures in gut and gills, the progressive activation of pancreatic and intestinal digestive enzymes, swimming bladder inflation, completion of eye retina layers, development of lymphoid organs and acquisition of full immunological capacities, are dependent on complex mechanisms that regulate cell differentiation, organogenesis and the adequate functionality of organs and tissues (Alami-Durante et al 2007;Campinho et al 2010;Johnston 2006;Power et al 2008;Yúfera and Darias 2007;Zapata et al 2006). Any failure in these processes, highly dependent on the nutritional and environmental conditions as well as on the response capacity of the developing larvae to external stimuli, causes malformations, developmental delays, poor growth and massive mortalities (Barahona-Fernandez 1982;Johnston et al 1998;Koumoundouros et al 2009;Polo et al 1991;Villeneuve et al 2005;Yúfera et al 1993).…”