Transcriptome Analysis of Effects of Folic Acid Supplement on Gene Expression in Liver of Broiler Chickens

Abstract

Folic acid is a water-soluble B vitamin, and plays an important role in regulating gene expression and methylation. The liver is the major site of lipid biosynthesis in the chicken. Nevertheless, how gene expression and regulatory networks are affected by folic acid in liver of broilers are poorly understood. This paper conducted the RNA-seq technology on the liver of broilers under folic acid challenge investigation. First, 405 differentially expressed genes (DEGs), including 157 significantly upregulated and 248 downregulated, were detected between the control group (C) and the 5 mg folic acid group (M). Second, 68 upregulated DEGs and 142 downregulated DEGs were determined between C group and 10 mg folic acid group (H). Third, there were 165 upregulated genes and 179 downregulated genes between M and H groups. Of these DEGs, 903 DEGs were successfully annotated in the public databases. The functional classification based on GO and KEEGG showed that “general function prediction only” represented the largest functional classes, “cell cycle” (C vs. M; M vs. H), and “neuroactive ligand-receptor interaction” (C vs. H) were the highest unique sequences among three groups. SNP analysis indicated that numbers of C, M and H groups were 145,450, 146,131, and 123,004, respectively. Total new predicted alternative splicing events in C, M, and H groups were 9,521, 9,328, and 8,929, respectively. A protein-protein interaction (PPI) network was constructed, and the top 10 hub genes were evaluated among three groups. The results of real time PCR indicated that mRNA abundance of PPARγ and FAS in abdominal fat of M and H groups were reduced compared with the C group (P < 0.05). Ultramicroscopy results showed that folic acid could reduce lipid droplets in livers from chickens. Finally, contents of LPL, PPARγ, and FAS in abdominal fat were decreased with the folic acid supplmented diets (P < 0.01). These findings reveal the effects of folic acid supplemention on gene expression in liver of broilers, which can provide information for understanding the molecular mechanisms of folic acid regulating liver lipid metabolism.

Folic Acid: Sources, Chemistry, Absorption, Metabolism, Beneficial Effects on Poultry Performance and Health

“…When in the liver, FA will be metabolized by several enzymes such as dihydrofolate reductase (DHFR), 5,10methylenetetrahydrofolate reductase (5,10-MTHFR), and tetrahydrofolic acid (THF) [7]. FA catalyzes the reduction of dietary FA and dihydrofolate in the liver to become THF, while the central reaction in folate metabolism is carried out by 5,10-MTHFR [34].…”

“…In comparison, a diet of 4 mg of FA/kg for eight weeks could impact old laying hens by lowering serum uric acid and young laying hens by lowering serum glucose levels [50]. e supplementation of FA by as much as 5-10 mg/kg in the diet could also reduce the droplet size of liver lipids and LPL, PPARc, and FAS in abdominal fat, indicating that FA affects FA gene expression in the liver [7]. Moreover, Yu et al [8] found that the supplementation of folate 0-16 mg/L could reduce FAS and CCAAT/enhancer-binding protein (C/EBPα) gene expression by altering the methylation level of the gene promoter.…”

“…is decrease in quality will initiate economic losses for farmers [6]. Factors that stimulate these problems include genetics, environment, and nutrition [7].…”

Folate inhibits lipid deposition via the autophagy pathway in chicken hepatocytes

“…Folate (vitamin B9) is stored and processed mainly in the liver ( Hu et al, 2016 ; Zhang et al, 2021 ). Folic acid is closely involved in mitochondrial one-carbon metabolism, providing the methyl group important for nucleic acid methylation and synthesis, amino acid, and antioxidant homeostasis ( Tibbetts and Appling, 2010 ; Ducker and Rabinowitz, 2017 ; Lyon et al, 2020 ; Annibal et al, 2021 ).…”

“…Folic acid dietary supplementation can increase folate content in eggs ( Hebert et al, 2005 ) and potentially increase body weight gain and feed efficiency of broilers ( Rao et al, 2022 ; Savaram et al, 2022 ). Folate perfusion can decrease hepatic lipogenesis, suppress adipogenesis, and reduce abdominal fat content in broilers, the underlying molecular mechanism of which was revealed by transcriptome sequencing ( Liu et al, 2019 ; Zhang et al, 2021 ). It was further discovered that paternal folate treatment could trans-generationally regulate lipid and glucose metabolism in broiler offsprings ( Wu et al., 2019 ), as demonstrated by in ovo folate feeding experiments as well ( Li et al, 2016 ; Liu et al, 2016 ).…”