Doungporn Amornlerdpison, Teerawat Rattanaphot, Sudaporn Tongsiri, Chutima Srimaroeng, and Kriangsak Mengumphan

DOI: 10.14456/sjst-psu.2019.162

pp. 1287 - 1293

Abstract

Freshwater fish oil (FFO) was extracted from by-products of the fisheries industry. The amounts of omega-3, 6, and 9
fatty acids in the FFO were 1.38, 12.29, and 42.9 g/100 g, respectively. The diet of Nile tilapia was supplemented with FFO for 4
months to evaluate the effect of FFO on gene expression of antioxidant enzymes and growth-associated immune response. Nile
tilapia supplemented with 1% and 1.5% FFO demonstrated growth. Gene expression of antioxidant enzymes including superoxide dismutase, catalase, and glutathione and cytokines of immunity, including TNF-α, IL-1β, and IgM were determined. Three
antioxidant enzymes and immune cytokines in the liver tissue were not statistical different among the experimental groups, but
expression of GPx and IgM increased in the kidneys of the FFO-supplemented Nile tilapia. IL-1β gene expression in the kidneys
also significantly increased. This indicated that the proinflammatory cytokine IL-1β might be enhanced by omega-6 fatty acid.
FFO supplemented in fish feed can improve growth, but the related immune gene expressions remain unclear.