When fed with 5% and 10% supplementation diets the survival rate
was higher (85% and 80%) and consequently resulted in a lower cumulative
mortality (15% and 20%). Numerous studies indicate similar
trends in many fishes fed with herbal immunostimulants against pathogens. In the present
work, fish fed with any enriched diet registered significantly improved
SGR, FCR, lysozyme, phagocytosis, respiratory burst, complement activities,
and survival rate after week 3. However, such improvements did
not manifest with any diet during the weeks 1 and 2. This study indicates
that at the chosen doses the positive effects of the herb was not marked. Furthermore, the precise mechanism of how R. apiculata extracts
stimulate growth and non-specific immunity and increase the
survival rate of A. sebae is not clearly understood and further research
on this aspect is needed in other fishes against the pathogen.