Journal: |
Comparative Biochemistry and Physiology, Part B
Elsevier Inc.
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Abstract: |
The red pepper (Capsicum annuum) has gained great attention recently because of its biological and pharmacological
characteristics. The present approach aimed to evaluate the effects of C. annuum alcoholic extract (CAE)
supplementation on Nile tilapia (Oreochromis niloticus) growth performance, physiological status, some metabolic,
immune, and regulatory genes expression, and resistance against Streptococcus agalactiae infection. Fish
(22.26 ± 0.19 g) were assigned to four treatments (five replicates, each with 10 fish replicate 1) and fed tested
diets for 60 days. The experimental diets were supplemented with CAE at 0, 0.4, 0.8, and 1.6 g kg, 1 expressed as
CAE0, CAE0.4, CAE0.8, and CAE1.6, respectively. The findings exhibited that CAE dietary supplementation
improved growth performance, feed utilization, elevated growth hormone level, and digestive enzyme activities
(amylase and protease), and lowered leptin hormone in a level-dependent manner. Boosting the mRNA
expression of the transporter proteins (solute carrier family 15 member 2 and solute carrier family 26 member 6)
and insulin-like growth factor-1 genes with a decrease in the myostatin gene expression was noticed in the CAEfed
groups. The innate immune (serum bactericidal activity %, complement 3, and phagocytic activity %) and
antioxidant (glutathione peroxidase and total antioxidant capacity) parameters were significantly (p < 0.05)
improved, and the serum malondialdehyde level was significantly decreased by CAE dietary inclusion. A marked
upregulation in the mRNA expression of interleukins (il-1β, il-6, il-8, and il-10), transforming growth factor-β,
glutathione peroxidase, and glutathione synthetase genes were observed in CAE-fed groups. Dietary CAE
decreased the cumulative mortalities after the challenge with S. agalactiae by 20, 13.33, and 10% in CAE0.4,
CAE0.8, and CAE1.6, respectively, compared to the control (40%). Overall, dietary supplementation with CAE
could improve growth performance and physiological status, and modulate the expression of several regulatory
genes in Nile tilapia. The recommended level of CAE is 1.6 g kg 1 to augment growth and health status.
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