Abstract: |
The current perspective is a pioneering trial to assess the efficacy of the dietary supplementation
of Alchemilla vulgaris powder (AVP) in the diet of Nile tilapia (Oreochromis niloticus) on
growth performance, blood picture, hepatic and renal biomarkers, immune status, and serum and
tissue antioxidant capacity and to investigate the resistance against Flavobacterium columnare challenge.
Fish (n = 360) were distributed into six groups (three replicates each) and received increasing
AVP supplementation levels (0, 2, 4, 6, 8, and 10 g kg−1) for 60 days. Furthermore, fish were exposed
to the bacterial challenge of a virulent F. columnare strain and maintained under observation for 12
days. During the observation period, clinical signs and the cumulative mortality percentage were
recorded. The results demonstrated that the growth performance, feed conversion ratio, and hematological
profile were noticeably enhanced in the AVP-supplemented groups compared to the control.
The most promising results of weight gain and feed conversion ratio were recorded in the
groups with 6, 8, and 10 g AVP kg−1 diets in a linear regression trend. The levels of hepatorenal
function indicators were maintained in a healthy range in the different dietary AVP-supplemented
groups. In a dose-dependent manner, fish fed AVP dietary supplements displayed significant augmented
serum levels of innate immune indicators (lysozyme, nitric oxide, and complement 3) and
antioxidant biomarkers (Catalase (CAT), superoxide dismutase (SOD), total antioxidant (TAC), and
reduced glutathione (GSH) with a marked decrease in myeloperoxidase (MPO) and malondialdehyde
(MDA) levels). Likewise, hepatic CAT and SOD activities were significantly improved, and
the opposite trend was recorded with hepatic MDA. The highest AVP-supplemented dose (10 g/kg)
recorded the highest immune-antioxidant status. Based on the study findings, we highlight the efficacy
of AVP as a nutraceutical dietary supplementation for aquaculture to enhance growth, physiological
performance, and immune-antioxidant status and as a natural economic antibacterial agent
in O. niloticus for sustaining aquaculture. It could be concluded that the dietary supplementation of
10 g AVP/kg enhanced O. niloticus growth, physiological performance, immune-antioxidant status,
and resistance against F. columnare.
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