Effects of age on growth in Atlantic bluefin tuna (Thunnus thynnus).

Atlantic Bluefin Tuna Thunnus thynnus (ABFT) is considered one of the most important socio-economic species but there is a lack of information on the physiological and molecular processes regulating its growth and metabolism. In the present study, we focused on key molecules involved in growth process. The aim of the present study was to associate molecular markers related to growth with canonical procedures like morphological measurements such as curved fork length (CFL) and round weight (RWT). The ABFT specimens (n = 41) were organized into three different groups A, B and C according to their age. The molecular analysis of liver samples revealed that igf1, igf1r and mTOR genes, involved in growth process, were differentially expressed in relation to the age of the fish. In addition, during the analyzed period, faster growth was evident from 5 to 8 years of age, after that, the growth rate decreased in terms of length yet increased in terms of adipose tissue storage, as supported by the higher fat content in the liver. These results are useful in expanding basic knowledge about the metabolic system of ABFT and provide new knowledge for the aquaculture industry.