Immunohistochemical localization of IGF-I, IGF-II and MSTN proteins during development of triploid sea bass (Dicentrarchus labrax)

The cellular localization of IGF-I, IGF-II and MSTN proteins was investigated during ontogenesis of triploid sea bass (Dicentrarchus labrax) by an immunohistochemical approach. The results were compared with those observed in diploids. IGF-I immunostaining was mainly observed in skin, skeletal muscle, intestine and gills of both diploids and triploids. From day 30 of larval life, IGF-I immunoreactivity observed in skeletal muscle, intestine, gills and kidney was stronger in triploids than in diploids. At day 30, triploids exhibited a standard length significantly higher than the one of diploids. Although IGF-II and MSTN immunoreactivity was detectable in different tissues and organs, no differences between diploids and triploids were observed. The spatial localization of IGF-I, IGF-II and MSTN proteins detected in this study is in agreement with previous findings on the distribution of these proteins in diploid larvae and fry. The highest IGF-I immunoreactivity observed in triploids suggests a possible involvement of ploidy in their growth performance.