Bong Joo Lee, So Young Kim, Hyo Rin Kang, Hyun Jeong Hwang, Mi So Seong, Ye Eun Jeong and Jae Hun Cheong*
In aquaculture, feed cost constitutes a large part of the total expense, and a dietary protein source is an important factor influencing both fish growth and feed cost. This study was performed to investigate the effects of extruded pellets containing soybean meal (SM) as a fish meal (FM) replacement on the liver of olive flounder, in terms of molecular biology. To investigate the effects of SM and FM on the expression of the genes involved in hepatic glucose and lipid metabolism and the immune response, real-time PCR was performed. SM increased the expression of genes involved in lipid metabolism and PPARγ. In addition, SM increased the expression of several immune-related genes, including TLR2, IRF3, IRF7, RELA, IL1β, IL8, and TNF. To identify the common factors regulating immune gene expression, we investigated the promoter regions of these genes. Comparative analysis of these factors showed that NF-κB binding elements were found on the promoters of all genes, except for TLR3. The promoter construct containing NF-κB mutant binding element was not activated by SM. These results suggest that gene expression may increase through activation of NF-κB signaling in the liver of olive flounder fed SM. This study will be helpful for developing improved extruded pellets.
Published Date: 2019-07-31; Received Date: 2019-07-02