  The SU(3) Haldane phase with adjoint representation provides the simplest
non-trivial symmetry-protected topological phases in the SU($N>2$) spin chains
for which a gapped system has been predicted. In this letter, I show how to
realize this phase in a two-species spinor Bose gas. The proposed system
consists of two intertwined species-dependent zigzag optical lattices with the
two species labeling the quark and antiquark states of SU(3) symmetry. The
Haldane phase is found connected to a position at which both the string order
and entanglement spectrum degeneracy are absent, signaling the appearance of a
critical point. I show how to understand this absence by a ground-state ansatz.
