We generalize the perturbations theory of loop quantum cosmology to a
hydrodynamical form and define an effective curvature perturbation on an
uniform density hypersurfaces ζe. As in the classical cosmology,
ζe should be gauge-invariant and conservation on the large scales. The
evolutions of both the adiabatic and the non-adiabatic perturbations for a
multi-fluids model are investigated in the framework of the effective
hydrodynamical theory of loop quantum cosmology with the inverse triad
correction. We find that, different from the classical cosmology, the evolution
of the large-scales non-adiabatic entropy perturbation can be driven by an
adiabatic curvature perturbation and this adiabatic source for the
non-adiabatic perturbation is a quantum effect. As an application of the
related formalism, we study a decay model and give out the numerical results.Comment: 10 pages, 3 figure