Moreover, there are similar reports of an increase in NBT activity
over controls in rohu juveniles fed 0.1%, 0.5% and 1.0% of garlic [8].
Furthermore, serum lysozyme activity plays a key role in the
lysis of bacterial pathogens, activation of phagocytosis and haemolytic
complement activity. Serum lysozyme activity presents
a first line of defence, with lytic factors by preventing adhesion and
colonisation of bacterial pathogens, thus, resulting in the prevention
of infections and disease [28,29]. In this present study, the
serum lysozyme activity was higher in dietary garlic treated groups
than the control 14, 21 and 28 days after stopping supplemented
feed administration. Definitely such profound enhancement in this
innate immune factor stemming from dietary supplementation
may have provided the observed protection against this pathogen.
Similarly other authors [30] had also observed significantly
enhanced lysozyme activity after 1, 2 or 3 weeks treatments of
tilapia with medicinal plant Ecliptaalba leaf extracts.
Certainly, the proliferation rate and number of lymphocytes
produced are very important for the magnitude and duration of
protection against disease [31]. This supports the view that the
persistence of an immune activator may be a critical factor in
maintaining long-term protection against disease causing situations.
With garlic, various bioactive compounds have been found to
exhibit immunological properties and are detectable in blood after
oral uptake [32e34]. Also in comparison to this study, the CF was
reduced in the work involving rainbow trout reported by [14].
Furthermore, it is noteworthy that CF has been regarded as a useful
bio-indicator of stress [35], and is reflected in changes in energy
budgets [36]. In the present study, it is possible that the deterioration
in CF may be a consequence of disrupted metabolic
processes, resulting from the withdrawal of garlic from the diet.
Furthermore, the changes in levels of blood electrolyte ions may be
explained by the reduced energy metabolism as considered
previously by [37]. It is interesting to note that similar results were
documented in rainbow trout treated with central nervous seizure
agents