Dietary vitamin mix levels influence the ossification process in European sea bass (Dicentrarchus labrax) larvae

Abstract

The influence of dietary vitamins on growth, survival, and morphogenesis was evaluated until day 38 of posthatching life in European sea bass larvae (Dicentrarchus labrax). A standard vitamin mix (VM), at double the concentration of the U.S. National Research Council's recommendations, was incorporated into larval feeds at 0.5%, 1.5%, 2.5%, 4.0%, and 8.0% to give treatments VM 0.5, VM 1.5, VM 2.5, VM 4.0, and VM 8.0, respectively. The group fed the VM 0.5 diet all died before day 30. At day 38, the larvae group fed VM 1.5 had 33% survival, while the other groups, with higher vitamin levels, showed at least 50% survival. The higher the percentage VM in the diet, the lower the percentage of column deformities. High dietary vitamin levels positively influenced the formation of mineralized bone in larvae: the higher the dietary vitamin level, the higher the ossification status. In the larvae group fed at the highest vitamin levels, we observed a temporal sequence of coordinated growth factor expression, in which the expression of bone morphometric protein (BMP-4) preceded the expression of IGF-1, which stimulated the maturation of osteoblasts (revealed by high osteocalcin expression levels). In groups fed lower proportions of vitamins, elevated proliferator peroxisome-activated receptors (PPAR-gamma) expression coincided with low BMP-4 expression. Our results suggest that high levels of PPAR-gamma transcripts in larvae-fed diets with a low VM content converted some osteoblasts into adipocytes during the first two weeks of life. This loss of osteoblasts is likely to have caused skeletal deformities.

The development of contemporary European sea bass larvae (Dicentrarchus labrax) is not affected by projected ocean acidification scenarios

“…This mechanism still needs to be elucidated. Nonetheless, our transcriptomic analyses showed that the expression pattern of osteocalcin, a marker of bone differentiation and mineralization (Mazurais et al 2008; Darias et al 2010a), was not affected by ambient . This suggests that the observed faster skeletogenesis may be an indirect effect of internal pH homeostasis, rather than the result of a specific calcification regulatory pathway.…”

Ossification of Atlantic cod ( Gadus morhua ) – Developmental stages revisited

“…Previously, it has been shown that both bone/cartilage ratio and mineralization patterning coincide with regulation of osteocalcin gene expression (Bensimon-Brito et al, 2012;Mazurais et al, 2008).…”

Fitness difference between cryptic salinity-related phenotypes of sea bass (<em>Dicentrarchus labrax</em>)

“…Varsamos et al 2006, Terova et al 2007, Mazurais et al 2008), as they retrieved, e.g., better repeatability of C q values and efficiencies (details not reported). GHR expression was not previously investigated in sea bass.…”