Impacts of Cinnamomum tamala leaf extract on growth, skin mucosal and serum immunity, antioxidant activity, and expression of cytokine genes in Cyprinus carpio fingerlings
摘要
This study aimed to assess the effect of Cinnamomum tamala leaf-extract (CTE) on the growth, immune response, antioxidant status, gene expression, and disease resistance of Cyprinus carpio. Over a 70-day period, fish (8.82 ± 0.04 g) were fed diets supplemented with graded levels of CTE (mg/kg): 0 (Control), 200 (CTE2), 300 (CTE3), 400 (CTE4), 500 (CTE5), and 600 (CTE6). Cytokine gene expression was studied 3 days post-challenge with A. hydrophila. CTE at 400–600 mg/kg maximized the growth performance. Key immune parameters, such as total protein, lysozyme, ACH50, alkaline phosphatase, skin mucosal protease activity, serum phagocytosis, and peroxidase levels were enhanced (P < 0.05) in CTE4 and/or CTE5 than in the control. Dietary CTE did not influence serum glucose, cortisol, creatinine, urea, total immunoglobulin, or liver metabolic enzyme levels. Intestinal amylase activity, and serum antioxidant levels were higher in CTE4-CTE6; whereas, serum MDA level was decreased in CTE5 (P < 0.05). The 15-day relative post-challenge survival was highest in CTE5 (54.76%). The transcript levels of sod, cat, and nrf2 were strongly upregulated in the liver tissues of CTE4 and CTE5; whereas keap1 transcription was downregulated in CTE5. The expression of tnf-α, il-1β, and hsp70 was down-regulated in CTE4 and CTE5. Conversely, il-10 expression was significantly upregulated in liver tissues of CTE4. The expression of occludin, occludin 7, and zo-1 were significantly upregulated in the intestinal tissues of CTE4 and CTE5. Overall, dietary CTE at appropriate level can enhance growth performance, immunity, and disease resistance in C. carpio.
HighlightsC. tamala leaf extract (CTE) at 400–500 mg/kg improved growth performance of Cyprinus carpio. Dietary CTE at 400–500 mg/kg modulated the skin mucosal immunity of fish. CTE enhanced the resistance against Aeromonas hydrophila challenge. CTE at 400–500 mg/kg enhanced serum antioxidant enzymes.