The polarized structure functions of $^3He$ and $^3H$ nuclei are calculated in NLO approximation, considering
and disregarding the light sea quark symmetry breaking. We employ the polarized structure function of the
nucleons within the nucleus extracted from our two recent analysis on polarized DIS data and on polarized
DIS+SIDIS data. Since the data of the second analysis cover a bigger range of Bjorken variable, both SU(2)
and SU(3) symmetry breaking is considered within the analysis. Then we calculate and compare the polarized
structures of nuclei extracted from both scenarios. Also the Bjorken and ELT sum rules are calculated using
the moments of structure functions. The results are compared with experimental data and the differences are investigated.