Herb extracts have a potential application as an
immunostimulant in fish culture, primarily because
they can be easily obtained, are not expensive and act
against a broad spectrum of pathogens. Most of the
herbs and herb extracts can be given orally, which is
the most convenient method of immunostimulation.
However, the effect is dose-dependent, and there is
always a potential for overdosing (Yin et al. 2006);
consequently, dosage optimization is stron