The Effects of Early Temperature and Live Feeds on the Development of White Muscle in Greater Amberjack (Seriola dumerili)

Greater amberjack (Seriola dumerili) shows potential for Mediterranean aquaculture due to its swift growth, consumer appeal, and commercial value. However, challenges in juvenile production, such as growth dispersion and unsynchronized development, impede further expansion. This study explores the impact of rearing temperature and live feed types on early white muscle development in greater amberjack larvae. Findings reveal substantial effects of temperature and diet on larval development, highlighting that the combination of 24 °C and a copepod + rotifer co-feeding scheme resulted in the highest axial growth rate, whereas rotifer-fed larvae at 20 °C exhibited a slower pace. Incorporating both histological and gene expression analyses, the study underscores temperature’s significant influence on white muscle development. Among larvae reared at 24 °C, the two live feed types led to phenotypic variations at metamorphosis, with rotifers supporting longer larvae featuring a smaller total cross-sectional area compared to copepods. Gene expression analysis indicates heightened mylpfb and myog expression at 24 °C during early larval stages, suggesting increased hyperplasia and myoblast differentiation. This study highlights the necessity of considering both temperature and feed type in larval rearing practices for optimal muscle development, and further research exploring combined diets during rearing could offer insights to enhance amberjack aquaculture sustainability.