RNAseq reveals modulation of genes involved in fatty acid biosynthesis in chicken liver according to genetic background, sex, and diet

Increases in chicken production are mainly due to specialised breeds. However, local breeds are of increasing importance, known for ability to adapt to the environment and unique products. Conventional poultry products contain lower levels of n-3 fatty acids (FAs) compared to those obtained from local breeds, therefore the aim of this study was to evaluate the modulation of expression of genes involved in long-chain polyunsaturated FA (PUFA) biosynthesis pathways according to genetic background, diet conditions, and sex. Animals from two local breeds and a commercial line were fed different diets: control and experimental diet (10% linseed supplementation). For each breed and diet group, both sexes were reared. The RNA was extracted from 36 liver samples and sequenced by RNAseq method. Bioinformatic analysis was carried out to find differentially expressed genes from comparisons between experimental groups. Results showed low impact of diet on differentially expressed genes related to FA biosynthesis, but linseed diet increased percentage of n-3 FAs of liver. Sex and genetic background determined the differential expression of genes related to long-chain PUFA biosynthesis. Specifically, females of local breeds shared 23 up-regulated genes when compared to their respective commercial line groups. Some of the shared genes had a role in de novo triglyceride biosynthesis (MTTPL and GPAM), and in de novo FA biosynthesis (ACACA and SCD) was detected. In conclusion, local breeds are able to better adapt to a diet rich in PUFA, by triggering certain transcriptomic shifts in the liver that allow birds to process the high PUFA content provided by diet.