Abstract: |
African catfish (Clarias gariepinus) were subjected to a 30-day feeding trial to determine
the appropriateness of using plant protein (PP) (soybean and sunflower meal) as a fishmeal (FM)
replacement in the diet and its effects on immune status, antioxidant activity, pituitary adenylate
cyclase-activating polypeptide (PACAP) gene expression, and disease resistance. A total of 150 C.
gariepinus (51.01 0.34 g) were randomly distributed among five groups in triplicate. Five experimental
diets were formulated to replace 0 (control), 33.5, 50, 66.5, and 100% FM with soybean and
sunflower meal to form the experimental diets (R0, R33.5, R50, R66.5, and R100, respectively). After
30 days, the diet containing PP for FM had no significant impact on total, and differential leukocyte
counts determined at the end of the feeding period. The total globulin concentration showed significantly
greater differences in the following order R0 > R33.5 > R50 > R66.5 > R100. The R0 group
had the highest concentration of serum
-globulin, while R100 had the lowest concentration. The
antioxidant status complements 3 (C3), lysozyme activity (LYZ), and antiprotease activity were not
significantly different between R0, R33.5, and R50 groups, while they were significantly lower in
R100. The serum nitric oxide activity (NO) exhibited significantly greater differences in the following
order R0 > R33.5 > R50 > R66.5 > R100. PACAP was significantly higher in the R33.5 group. The
highest cumulative mortality caused by Aeromonas sobria was recorded in the R100 group (60%)
and the lowest in the R0 group (30%). In conclusion, the results indicate that the immunological
responses and antioxidant status of C. gariepinus were not affected when they consumed a diet with
FM replaced by up to 50% with PP (SBM and SFM) with methionine and lysine supplementation,
but total globulin, NO, and cumulative mortality were impaired with a diet containing a 100%
FM replacement.
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