Alteration of Hepatic Gene Expression along with the Inherited Phenotype of Acquired Fatty Liver in Chicken

Abstract

Fatty liver is a widespread disease in chickens that causes a decrease in egg production and even death. The characteristics of the inherited phenotype of acquired fatty liver and the molecular mechanisms underlying it, however, are largely unknown. In the current study, fatty liver was induced in 3 breeds by a high-fat (HF) diet and a methionine choline-deficient (MCD) diet. The results showed that the dwarf Jingxing-Huang (JXH) chicken was more susceptible to fatty liver compared with the layer White Leghorns (WL) and local Beijing-You (BJY) breeds. In addition, it was found that the paternal fatty livers induced by HF diet in JXH chickens were inherited. Compared to birds without fatty liver in the control group, both offsprings and their sires with fatty livers in the paternal group exhibited altered hepatic gene expression profiles, including upregulation of several key genes involved in fatty acid metabolism, lipid metabolism and glucose metabolism (ACACA, FASN, SCD, ACSL5, FADS2, FABP1, APOA4 and ME1). This study uniquely revealed that acquired fatty liver in cocks can be inherited. The hepatic gene expression profiles were altered in chickens with the inherited phenotype of acquired paternal fatty liver and several genes could be candidate biomarkers.

Keywords: chicken; fatty liver; gene expression; inherited phenotype; susceptible breed.

Figure 1

Graphic representation of the experimental procedures and main results. * The F1 chickens of control, maternal and paternal groups were all fed normal diet. DE: differentially expressed.

Figure 2

Generation of three cross breeds to examine the inheritance of fatty liver. The control group (left) using JXH chickens fed with the basal diet, maternal inheritance group (middle) and paternal inheritance group (right) using JXH chickens with HF diet-induced fatty liver. Chickens from F0 with fatty liver are shown in red while those without fatty liver are in black. ♂ and ♀ represent the cock and the hen, respectively.

Figure 3

Typical features of fatty liver in terms of gross appearance and sections stained with hematoxylin-eosin(H&E) or oil red O (20×). The fatty liver appears yellow or light yellow and the edge of the liver is blunt and friable (a). Enlarged liver cells with abundant fat droplets of different sizes are present in the cytoplasm and liver leaflets lost the normal reticular formation (c,e). In comparison, the non-fatty liver was dark red with sharp edges, the texture was flexible and there were less fat droplets and clear reticular formations in liver leaflets (b,d,f). (a,c,e) were from one JXH chicken with HF diet; (b,d,f) from one JXH chicken with basal diet. Scale bar: 100 μm.

Figure 4

Typical H&E and oil red O stained liver sections (20×) from F1 generation of JXH chicken with or without fatty liver, paternal group (a,c); control group (b,d). Scale bar: 100 μm.

Figure 5

Serum lipid indices of all F1 JXH chickens in the control (C, n = 105), maternal (M, n = 80) and paternal (P, n = 82) groups. TG: triglyceride, CHOL: total cholesterol, LDL-CHOL: low-density lipoprotein, HDL-CHOL: high-density lipoprotein. * indicates p < 0.05 and ** indicates p < 0.01.

Figure 6

Volcano plot of differentially expressed genes (DEGs). Red, green and blue points represent significantly upregulated, downregulated and non-regulated genes, respectively. The abscissa is the fold change of the genes in different samples, ordinate is the variation difference of the gene expression with statistical significance. FL: paternal inheritance group, C: control group.

Figure 7

The most enriched gene ontology (GO) terms for the differentially expressed genes.

Figure 8

The pathway enrichment analyses for the DEGs.

Figure 9

Fold changes of fatty acid metabolism genes (ACC, FASN, SCD, FADS2) and lipid metabolism gene (FABP1) expression levels between P (paternal inheritance group) and C (control group) in F0 and F1 generations. ** indicates p < 0.01.

Figure 10

Fold changes of fatty acid metabolism gene (ACSL5), lipid metabolism gene (APOA4) and glucose metabolism gene (ME1) expression levels between P (paternal inheritance group) and C (control group) in the F0 and F1 generations. * indicates p < 0.05 and ** indicates p < 0.01.

Figure 11

Fold change of glucose metabolism gene, ISR4, expression level between P (paternal inheritance group) and C (control group) in the F0 and F1 generations. * indicates p < 0.05.