| Journal: |
Aquaculture
Elsevier B.V.
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| Abstract: |
Feed additives are edible ingredients that are very sparingly added to fish diets to improve the nutritional value
of feed, which in turn enhances fish growth and health. Most recent research focused on their single use, but little
is known about their combined application. Hence, a 7-week feeding trial was conducted to investigate the
consequences of the dietary addition of papaya (Carica papaya) leaf powder (CPP) with or without alpha-lipoic
acid (AL). The assessment encompassed the influence on growth, digestive capacity, body composition, physiological
and antioxidant response, as well as disease resistance (Aeromonas hydrophila challenge). Five treatments
containing 225 fish (N = 45 fish/group, 3 polyethylene cages /group, 15 fish/cage) with an average weight of
6.65 ± 1.85 g were haphazardly assigned. For 7 weeks, fish received basal diet supplemented with CPP alone or
with AL [0 % (control), 2 %CPP (CPP2), 3 %CPP (CPP3), 2 % CPP with 0.1 %AL (CPP2 + AL0.1), and 3 %CPP
with 0.1 %AL (CPP3 + AL0.1)]. Results displayed that CPP alone or with AL-fortified diets substantially boosted
growth performance and digestive enzyme activity (amylase, lipase, and trypsin). Dietary CPP alone or with AL
notably increased body lipid content, serum total protein, and hepatic antioxidant (reduced glutathione, superoxide
dismutase, and total antioxidant capacity) parameters. Moreover, blood glucose and hepatic malondialdehyde
showed lower values in the CPP alone or with AL diets. Surprisingly, the combination groups
especially the CPP2 + AL0.1 group achieved the best results (P < 0.05) for these variables. Fifteen days postchallenge
with A. hydrophila, the cumulative mortality declined among fish fed CPP alone or with AL diets,
where the CPP2 + AL0.1 group did not record any mortality. Overall, the dietary intervention of CPP (2 %) with
LA (0.1 %) by their synergistic potential can promote disease resistance, physiological-antioxidant status,
growth, and digestive capacity of Nile tilapia. These advantageous outcomes can support the development of
sustainable aquaculture.
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