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.

Folate plays an important role in DNA and RNA synthesis by donating methyl groups. To investigate the effects of maternal folate deficiency (FD) on the abdominal adipose transcriptome and on the accumulation of lipid droplets in the liver tissue of chicken offspring, differentially expressed genes (DEGs) of FD were identified with digital gene expression tag profiling. Ultramicroscopy suggested that the size of lipid droplets in hepatocytes increased with FD, while the lipid droplets population number was largely not affected. The serum parameters assay showed that the concentrations of MTHFR (476.57 vs. 395.27), DHFR (45.056 vs. 38.952), LPL (50.408 vs. 48.677), HCY (4.354 vs. 3.836), LEP (9.951 vs. 8.673), and IGF2 (1209.4 vs. 1027.7) in offspring serum of the FD group were significantly higher than those of the normal folate (NF) group ( P < 0.01). The 442 DEGs between NF and FD groups were identified by digital gene expression profiling. Considering the DEGs in the FD groups vs. NF groups, 179 genes were upregulated while 263 downregulated, and in particular, 145 upregulated and 214 downregulated DEGs were successfully annotated with the nonredundant database. Gene Ontology analysis showed that FD mainly affected cellular processes, cell part and binding, cell killing, virions, and receptor regulator activity. With pathway analysis, it indicated that 123 unigenes were assigned to 115 KEGG pathways, but only five of 115 these pathways were significantly enriched with P values ≤ 0.05. Taken together, these results provide a foundation for further studying the responses of offspring to maternal FD in breeding chickens.

In this study, we aimed to investigate the influence of maternal folate deficiency on the production performance and serum parameters of broiler offspring. The 120 healthy female broilers (30-week-old) were randomly allotted into two groups. The groups were either fed a basal diet supplemented with 2.0mg/kg folate (NF) or basal diet (FD). The experiment lasted 12 weeks, and 120 fertilized eggs were collected from each group for hatching. In total, 80 chicks were selected from each group and fed under the same conditions. No significant difference was observed in the average daily feed intake, average daily gain, and feed to gain ratio of 21- and 42-day-old broilers between NF and FD groups (P > 0.05). Moreover, slaughter performance of 21- and 42-day-old broiler offspring were not affected by the maternal FD. The subcutaneous fat thickness at the age of 21 days increased significantly by maternal FD (P < 0.01); however, there was no significant difference between the two groups at 42 days of age (P > 0.05). Similarly, no significant differences were detected in the intermuscular fat width, lipid percentage in the liver, breast muscle, and thigh muscle between the NF and FD groups at 21- and 42-days of age (P > 0.05). Serum concentrations of MTHFR, DHFR, LEP, IGF2, and HCY in the 42-day-old broilers were significantly increased by maternal FD (P < 0.01), but those in the 21-day-old broilers were not affected by maternal FD (P > 0.05). Additionally, serum concentration of HSL at 21 days of age and LPL at 42 days of age was enhanced by maternal FD, respectively (P < 0.05). These findings indicated that maternal folate deficiency increased some serum parameters of 42-day-old broiler offspring, but had no influence on production performance and fat traits of 21- and 42-day-old offspring.