  We study the full counting statistics (FCS) of electron tunneling through a
multi-terminal quantum dot in the Kondo regime within the slave-boson mean
field theory. By employing the A.O. Gogolin and A. Komnik's method of
calculating the FCS generating function based on the nonequilibrium Green's
function [Phys. Rev. B {\bf 73}, 195301 (2006)], we obtain the counting field
$\lambda$-dependent self-consistent equations for the mean values of the
slave-boson fields and the explicit expression for the derivative of the
adiabatic potential of the system with respect to the counting fields.
Performing perturbative expansion to the first order of $\lambda$, we find an
extra contribution to the shot noise due to the bias-induced Bose field
fluctuation, and then confirm that the nonequilibrium particle number
fluctuation plays an important role in the current noise of the Kondo dot:
enhancement of the current auto-correlation and a positive current
cross-correlation.
