Culture salinity modulates Nrf2 antioxidant signaling pathway and immune response of juvenile Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus) under different dietary protein levels. Issue 117 (October 2021)

• Record Type: Journal Article
• Authors: Liang, Hualiang; Wu, Longhua; Hamunjo Chama, Majory Kabwe; Ge, Xianping; Ren, Mingchun; Chen, Xiaoru; Pan, Liangkun; Xia, Dong
• Is Part Of: Fish & shellfish immunology. Issue 117(2021)
• Page Start: 220
• Page End: 227
• Publication Date: 2021-10
• Subjects: GIFT -- Dietary protein level -- Salinity -- Nrf2 and NF-κB signaling pathway -- Immune response; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2021.08.014
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: This study aimed to evaluate that dietary protein levels and culture salinity levels affect the health status of juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus ). Graded protein levels of six diets were prepared, ranging from 18.20% to 49.49% (dry basis), and were used in cultured GIFT at two salinity levels (0‰ and 8‰) for 8 weeks. The results suggested that appropriate protein levels reduced pro-inflammatory gene expressions in the intestine including interleukin 1β (IL-1β), interleukin 8 (IL-8) and tumour necrosis factor-α (TNF-α) mRNA levels at two salinity levels ( P < 0.05 ). 8‰ salinity significantly decreased the expression levels of IL-1β, TNF-α and nuclear factor-kappa B (NF-κB) ( P < 0.05 ). The anti-inflammatory factor interleukin 10 (IL-10) was significantly increased by 36.42% protein level ( P < 0.05 ). Regarding antioxidant capacity, appropriate protein levels and 8‰ salinity significantly improved the antioxidant capacity of fish by regulating the activities of intestinal total superoxide dismutase (T-SOD), glutathione peroxidase (GPx), and the levels of glutathione (GSH) and malondialdehyde (MDA). Furthermore, appropriate protein levels and 8‰ salinity also significantly enhanced the antioxidant gene expressions associated with the Nrf2/keap1 signaling pathway by regulating the expression levels of heme oxygenase-1 (HO-1), GPx, catalase (CAT) and superoxide dismutase (SOD). According to GPx activities and the mRNA levels of IL-10, the optimum dietary protein levels for GIFT juveniles were 31.12%–32.18% (0‰) and 34.25–35.38% (8‰) based on second-degree polynomial regression analysis. The present study found that appropriate protein levels and 8‰ culture salinity are critical in maintaining the health of GIFT juveniles by improving antioxidant and immune capacity. Highlights: Protein deficiency could damage the body's immune capacity and antioxidant capacity. Compared to 0‰ culture salinity, 8‰ culture salinity could improve antioxidant and immune capacity. The levels of protein and culture salinity affected antioxidant and immune capacity through the Nrf2 and NF-κB signaling pathway. The optimum dietary protein levels were 31.12%–32.18% (0‰) and 34.25–35.38% (8‰) based on immunity and antioxidant.