Effects of Vitamin E with Different Levels or Sources of Dietary Lipid on the Growth and Expression of Inflammatory, Oxidative Stress, and Apoptotic Genes in the Head Kidney of Olive Flounder, Paralichthys olivaceus

This study has assessed the effects of vitamin E (-E, +LE, +HE; 0, 100, 1000 mg/kg, respectively) in fish diets containing high levels (HL; 10%) of fish oil (FO) or mixed vegetable oils (VO) on the growth and inflammatory, oxidative stress, and apoptotic gene expression in the head kidney of olive flounder, Paralichthys olivaceus. Consequently, the highest weight gain was achieved in the FO group and the lowest in the HL-VO+LE group. The gene expression levels of each group were compared to the 5% FO group. The 5% VO group showed higher expression levels of tumor necrosis factor (TNF) , interleukin (IL)-1, and scinderin-like (ScinL) genes. Although lysozyme gene expression was higher in the HL-VO+LE group, the other gene expression levels of the HL-FO/VO+LE groups were not different from those of the FO group. The HL-FO/VO-E/+HE groups showed a higher TNF gene expression, but the cytochrome oxidase subunit III gene expression was higher in the HL-FO-E and HL-VO+HE groups. Lysozyme gene expression was higher in the HL-FO-E and HL-VO-E/+HE groups. IL-6 and ScinL gene expression were higher in the HL-VO-E and HL-VO+HE groups, respectively. In conclusion, mixed VO and too high or too low vitamin E levels in fish diets may affect inflammatory, oxidative stress, and apoptotic gene expression in the head kidney of olive flounder.