Boundary fermion currents and subleading order chiral anomaly in the AdS/CFT correspondence

We construct a wave-functional whose argument couples to boundary fermion currents in the AdS/CFT correspondence. Using this we calculate the contributions from bulk fermions to the chiral anomaly that give the subleading order term in the exact $N$-dependence of the chiral anomaly of ${\cal N}=4$ SYM. The result agrees with the calculation of Bilal & Chu.