Effects of soy-lecithin on lipid metabolism and hepatic expression of lipogenic genes in broiler chickens

The purpose of this experiment was to determine the effects of soy-lecithin on the lipid metabolism and expression of lipogenic genes in the liver of broiler chickens. Arbor Acres (AA) chicks growing from 1 to 42 days of age were randomly divided into 4 groups and fed corn-soybean basal diets containing 0% soy-lecithin (control), 0.5% soy-lecithin (SL1), 1% soy-lecithin (SL2), 2% soy-lecithin (SL3), respectively. At the end of experiment, samples of serum were taken for analyses of metabolites/hormones and liver tissue was collected to quantify expression of selected genes. The abdominal fat was removed and samples of thigh muscle and breast muscle also were collected. The hepatic expression of the genes encoding malic enzyme (ME), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), sterol regulatory element binding protein-1 (SREBP-1), stearoyl-CoA (Δ9) desaturase 1 (SCD1) and liver fatty acid binding protein (L-FABP) were determined with reverse transcription-polymerase chain reaction (RT-PCR) using SYBR green as a flourophore monitored in a real time mode. The study showed that the percentage of abdominal fat and liver fat were not significantly affected by soy-lecithin (P >0.05). SL2 group had the highest percentage of thigh muscle fat compared with other groups (P <0.05), but soy-lecithin had no significant effect on the percentage of breast muscle fat and the width of inter-muscular fat (P >0.05). Serum concentration of total serum cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were reduced by soy-lecithin, whereas high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were improved (P <0.05). The thyroid-stimulating hormone (TSH) and insulin (INS) were elevated in SL3 group (P <0.05). Furthermore, abundance of ME, FAS, ACC, SREBP-1, L-FABP and SCD1 mRNA were greater (P <0.05) in SL3 group. The results indicate that soy-lecithin alters the serum hormone levels and affects hepatic gene expression and thereby regulates fat metabolism of broilers.