Answer
The strangeness is not conserved.
Work Step by Step
The proton $p$ has strangeness $0$
The antiproton $\bar{p}$ has strangeness $0$
The $\Lambda^0$ has strangeness $-1$
The $\Sigma^+$ has strangeness $-1$
The $e^-$ has strangeness $0$
The left side of the proposed reaction has net strangeness $0$ while the right side of the proposed reaction has net strangeness $-2$
Therefore, the strangeness is not conserved.
