  Using the known experimental data for the hyperon semileptonic decay
constants, we calculate integrated quark densities $\Delta q_\Lambda$ and $%
\Delta \Sigma_\Lambda$ for the hyperon $\Lambda$ with flavor SU(3) symmetry
breaking taken into account. Symmetry breaking is implemented with the help of
the chiral quark-soliton model in an approach, in which the dynamical
parameters are fixed by the experimental data for six hyperon semileptonic
decay constants. This parametrization allows us to reproduce the first moment
of the $g_1^{{\rm p}}(x)$ of the proton. For the $\Lambda$ we obtain: $\Delta
u_{\Lambda}=\Delta d_{\Lambda} \approx 0$ and $\Delta s_{\Lambda}$ of the order
of 1. Unfortunately large experimental errors of $\Xi^-$ decays propagate in
our analysis especially in the case of $\Delta\Sigma_{\Lambda}$ and $\Delta
s_{\Lambda}$. Only if the errors for these decays are reduced, the accurate
theoretical predictions for $\Delta\Sigma_{\Lambda}$ and $% \Delta s_{\Lambda}$
will be possible.
