Morphological Differences of White Muscle Fibers and Genetic Diversity of Fast and Slow Growing Atlantic Sturgeons (Acipenser oxyrinchus)

The aim of this study was to establish causes of variation in body weight of Atlantic sturgeons reared for reintroduction program. Substantial disproportion of individuals released into freshwaters may influence reintroduction success. Histological analysis of white muscle was conducted due to large share of this tissue in body weight. Comparison of morphological
structure of white muscle tissue showed significant statistical differences between the fast and the slow growing sturgeons. Mosaic hyperplasia (MH) was observed in white muscle tissue in both sturgeon groups, but the number of proliferating myonuclei was significantly higher in slow growing individuals. Genetic analysis applying 16 microsatellite loci revealed comparable levels of polymorphism and assigned the studied individuals into kin groups consisting of both fast and slow growing sturgeons. The study revealed that the slow growing group had higher growth potential in further stages of development, but the fast growing sturgeons based on the histological analysis of muscle fiber distribution were more advanced in muscle tissue growth. Moreover, difference in growth rate could be caused by complex polygenic inheritance of the trait.