Oxidative stress response in liver of broiler chickens supplemented with n-3 PUFA-rich linseed oil

The aim of this study was to investigate the oxidative stress response, at the transcriptional level, in chickens supplemented with n-3 polyunsaturated fatty acids (PUFAs). Twenty chickens were divided into two groups: the PALM group (N=10) received 5% palm oil in feed as a source of saturated fatty acids (SFA), while the LIN group (N=10) received 5% polyunsaturated linseed oil. We determined plasma and liver malondialdehyde concentrations that served as a marker of lipid oxidation and vitamin E, as a natural antioxidant. Additionally, plasma triglyceride and cholesterol concentrations and liver fatty acid (FA) composition were determined. The RNA was isolated from the liver, and a whole-chicken genome microarray analysis (Affymetrix) was performed to examine the expression of genes. Differential expression of selected candidate genes was confirmed using quantitative real-time polymerase chain reaction (qRT-PCR). Malondialdehyde concentration was higher and vitamin E concentration was lower in the LIN group. No differences in plasma triglyceride and cholesterol concentrations were observed. Liver FA composition reflected the FA composition of the diets. Clearly present prooxidative conditions due to the consumption of an n-3 PUFA-rich diet triggered an oxidative stress response through the up-regulation of NFE2L2 and PIK3R1 genes. Changes in liver transcriptome also suggest that PUFAs lower mitochondrial lipid oxidation and increase the degree of lipogenesis in chickens' livers.