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The liver performs a number of vital functions in the chicken. In order to identify unique gene expression patterns and link them to potential functions in the chicken liver, genes enriched in the liver of chickens needed to be investigated in a comparative manner. In this study, 41 liver-enriched genes were identified through chicken microarray, a...
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Context 1
... liver-enriched genes were identified by fold changes in the liver as compared to other tissues including the brain, fat, heart, kidney, lung, and muscle (Table 1). Microarray-based, high-throughput gene expression data were obtained from the GDS DataSet (GDS) of the GEO repository in the National Center for Biotechnology Information (NCBI) archives (www.ncbi.nlm.nih.gov/geo). ...Context 2
... this study, chicken microarray analysis revealed that expressions of 41 genes are more than 35-fold higher than an average expression value of other tissues listed in Supplementary Table S1 (Table 1). Liverenriched expression patterns of many of those genes ( Figure 1A) were further confirmed in other species. ...Context 3
... expression patterns of many of those genes ( Figure 1A) were further confirmed in other species. In detail, according to literature and public databases (GEO DataSets [GDS] 596 for humans and GDS 3142 for mice), those genes showed elevated expression patterns in the liver of humans, mice, and other species (Table 1; Supplementary Tables S1-S3). Comparative analysis identified 10 genes as liver-enriched within chickens, but not within mice or humans (PIT54, A2M, A2ML, SLCO1B3, GFRA3, ABCB1, COCH, CYP2W2, SERPINA5, and PRPS2). ...Context 4
... prevent PCR saturation effects during amplification, the number of PCR cycles was reduced until the saturation no longer occurs. Compared to various chicken tissues including subcutaneous adipose tissue, thymus muscle, pectoralis muscle, heart, kidney, and lung, those 13 genes (PIT54, A2M, PRPS2, ABCB1, SERPINA5, COCH, SLCO1B3, CYP2W2, CYP2C18, GFRA3, GAL8/AvBD8, A2ML2, and SULT) showed chicken liver-enriched expression patterns among various tissues ( Figure 1B) which is consistent with the microarray data (Table 1). Including PIT54, CYP2W2, GAL8/AvBD8, A2ML2, and SULT which are genes that exist only in birds, abundant expression of those 13 genes may be implicated in various liver functions in chickens. ...Citations
... A potential explanation for this discrepancy could be attributed to the metabolic responsiveness of the liver to nutritional fluctuations. Liver genes exhibit an active response to both low or high nutrition (Ahn et al., 2019). In contrast, IGF-1 can be secreted from other tissues that do not respond rapidly to nutritional changes during the adult stage (Laron, 2001). ...
Nutritional limitation is a common phenomenon in nature that leads to trade‐offs among processes competing for limited resources. These trade‐offs are mediated by changes in physiological traits such as growth factors and circulating lipids. However, studies addressing the sex‐specific effect of nutritional deficiency on these physiological variables are limited in birds. We used dietary restriction to mimic the depletion of resources to various degrees and investigated sex‐specific effects on circulating levels of insulin‐like growth factor 1 (IGF‐1) and triglycerides in Japanese quails (Coturnix japonica) subjected to ad libitum, 20%, 30% or 40% restriction of their daily requirement, for 2 weeks. We also explored the association of both physiological variables with body mass and egg production. While dietary restriction showed no effects on circulating IGF‐1, this hormone exhibited a marked sexual difference, with females having 64.7% higher IGF‐1 levels than males. Dietary restriction significantly reduced plasma triglyceride levels in both sexes. Females showed more than six‐fold higher triglyceride levels than males. Triglyceride levels were positively associated with body mass in females while showed not association in males. Overall, our findings revealed sex‐specific expression of physiological variables under dietary restriction conditions, which coincide with body size.
... The liver is an essential metabolic organ that performs exocrine and endocrine metabolic functions such as bile production, blood detoxification, regulation of circulating hormones, protein synthesis and regulation of glucose levels through glycogen storage [13]. In chickens, the liver is also the main site of de novo lipogenesis [14]. ...
Background
Nutrient availability during early stages of development (embryogenesis and the first week post-hatch) can have long-term effects on physiological functions and bird metabolism. The embryo develops in a closed structure and depends entirely on the nutrients and energy available in the egg. The aim of this study was to describe the ontogeny of pathways governing hepatic metabolism that mediates many physiological functions in the pHu + and pHu- chicken lines, which are divergently selected for the ultimate pH of meat, a proxy for muscle glycogen stores, and which differ in the nutrient content and composition of eggs.
Results
We identified eight clusters of genes showing a common pattern of expression between embryonic day 12 (E12) and day 8 (D8) post-hatch. These clusters were not representative of a specific metabolic pathway or function. On E12 and E14, the majority of genes differentially expressed between the pHu + and pHu- lines were overexpressed in the pHu + line. Conversely, the majority of genes differentially expressed from E18 were overexpressed in the pHu- line. During the metabolic shift at E18, there was a decrease in the expression of genes linked to several metabolic functions (e.g. protein synthesis, autophagy and mitochondrial activity). At hatching (D0), there were two distinct groups of pHu + chicks based on hierarchical clustering; these groups also differed in liver weight and serum parameters (e.g. triglyceride content and creatine kinase activity). At D0 and D8, there was a sex effect for several metabolic pathways. Metabolism appeared to be more active and oriented towards protein synthesis (RPS6) and fatty acid β-oxidation (ACAA2, ACOX1) in males than in females. In comparison, the genes overexpressed in females were related to carbohydrate metabolism (SLC2A1, SLC2A12, FoxO1, PHKA2, PHKB, PRKAB2 and GYS2).
Conclusions
Our study provides the first detailed description of the evolution of different hepatic metabolic pathways during the early development of embryos and post-hatching chicks. We found a metabolic orientation for the pHu + line towards proteolysis, glycogen degradation, ATP synthesis and autophagy, likely in response to a higher energy requirement compared with pHu- embryos. The metabolic orientations specific to the pHu + and pHu- lines are established very early, probably in relation with their different genetic background and available nutrients.
... In the avian species, CYP2C18 is a crucial subfamily of cytochrome P450 and a factor in susceptibility to chemical substances having xenobiotic metabolic activity [26]. In chicken, CYP2C18 is highly enriched in liver tissue, indicating its potential role in regulating hepatic lipogenesis [27]. Taken together, the above studies indicated that ACSS2, PCSK9, and CYP2C18 play key roles in lipogenesis, and the up-regulated 5-hydroxyisourate, alpha-linolenic acid, bovinic acid, linoleic acid, and trans-2-octenoic acid might serve as gut-liver signals to promote HFD-induced lipogenesis and fat deposition of chicken by enhancing the expression of ACSS2, PCSK9, and CYP2C18 in the liver. ...
Simple Summary
The gut microbiota can regulate lipid metabolism with its metabolic products through the gut–liver axis. In the present study, using an HFD-induced obese chicken model, we performed a multiple omics analysis using metabolomics and transcriptomics to identify gut–liver crosstalks involved in regulating the lipogenesis of chicken. The results showed that 5-hydroxyisourate, alpha-linolenic acid, bovinic acid, linoleic acid, and trans-2-octenoic acid might serve as signal molecules between the gut and liver. In the liver, they might enhance the expression of ACSS2, PCSK9, and CYP2C18 and down-regulate one or more genes of CDS1, ST8SIA6, LOC415787, MOGAT1, PLIN1, LOC423719, and EDN2 to promote the lipogenesis of chicken. Moreover, taurocholic acid might be transported from the gut to the liver and contribute to HFD-induced lipogenesis by regulating the expression of ACACA, FASN, AACS, and LPL in the liver. This study lays the foundations for further elucidation of the gut–liver crosstalk mechanisms underlying lipogenesis in chickens.
Abstract
Growing evidence has shown the involvement of the gut–liver axis in lipogenesis and fat deposition. However, how the gut crosstalk with the liver and the potential role of gut–liver crosstalk in the lipogenesis of chicken remains largely unknown. In this study, to identify gut–liver crosstalks involved in regulating the lipogenesis of chicken, we first established an HFD-induced obese chicken model. Using this model, we detected the changes in the metabolic profiles of the cecum and liver in response to the HFD-induced excessive lipogenesis using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) analysis. The changes in the gene expression profiles of the liver were examined by RNA sequencing. The potential gut–liver crosstalks were identified by the correlation analysis of key metabolites and genes. The results showed that a total of 113 and 73 differentially abundant metabolites (DAMs) between NFD and HFD groups were identified in the chicken cecum and liver, respectively. Eleven DAMs overlayed between the two comparisons, in which ten DAMs showed consistent abundance trends in the cecum and liver after HFD feeding, suggesting their potential as signaling molecules between the gut and liver. RNA sequencing identified 271 differentially expressed genes (DEGs) in the liver of chickens fed with NFD vs. HFD. Thirty-five DEGs were involved in the lipid metabolic process, which might be candidate genes regulating the lipogenesis of chicken. Correlation analysis indicated that 5-hydroxyisourate, alpha-linolenic acid, bovinic acid, linoleic acid, and trans-2-octenoic acid might be transported from gut to liver, and thereby up-regulate the expression of ACSS2, PCSK9, and CYP2C18 and down-regulate one or more genes of CDS1, ST8SIA6, LOC415787, MOGAT1, PLIN1, LOC423719, and EDN2 in the liver to enhance the lipogenesis of chicken. Moreover, taurocholic acid might be transported from the gut to the liver and contribute to HFD-induced lipogenesis by regulating the expression of ACACA, FASN, AACS, and LPL in the liver. Our findings contribute to a better understanding of gut–liver crosstalks and their potential roles in regulating chicken lipogenesis.
... In this study, FABP1 was upregulated in the liver of capons, which we speculated that this is affected by the alternation of fat deposition after caponization. As the most downregulated gene in liver, sulfotransferase (SULT) plays an important role in the xenobiotic detoxification of chicken livers (Ahn et al., 2019). ...
Chicken is widely accepted by consumers because of its delicate taste and abundant animal protein. The rooster after castration (capon) is believed to show better flavor, however, the molecular changes of the underpinned metabolism after castration is not yet understood. In this study, we aimed to figure out the alternation of meat quality and underpinned molecular mechanism via transcriptomic profiling of liver, spleen and hypothalamus as targeted organs in response to the castration. We identified differential expressed genes and their enriched functions and pathways in these organs between capon and rooster samples through RNA-seq analysis. In the liver, the lipid metabolism with targeted FABP1gene was found significantly enriched, which may be as one of the factors contributing to increased fat deposition and thus better meat flavor in capons than roosters, as predicted by the significantly lower shear force in capons than in roosters in meat quality experiments. However, the ability to xenobiotic detoxification and excretion, vitamin metabolism, and antioxidative effect of hemoglobin evidenced of the capon may be compromised by the alternation of SULT, AOX1, CYP3A5, HBA1, HBBA, and HBAD. Besides, in both the spleen and hypothalamus, PTAFR, HPX, CTLA4, LAG3, ANPEP, CD24, ITGA2B, ITGB3, CD2, CD7, and BLB2 may play an important role in the immune system including function of platelet and T cell, development of monocyte/macrophage and B cell in capons as compared to roosters. In conclusion, our study sheds lights into the possible molecular mechanism of better meat flavor, fatty deposit, oxidative detoxification and immune response difference between capons and roosters.
... On the other hand, PIT54 is an acute phase protein with an important inhibitory role in inflammation processes (Wicher and Fries, 2006), which is rapidly increased in the blood as a response to infectious agents or physiological stressors (O'reilly and Eckersall, 2014). PIT54 in the chicken plasma binds free haemoglobin to inhibit haemoglobin-mediated oxidation of lipid and protein (Ahn et al., 2019). Antinutritional effects of NSP are related to a reduction of BW and FCR, and can trigger a mild chronic inflammation in the gut (Cardoso Dal Pont et al., 2020). ...
Fast optimisation of farming practices is essential to meet environmental sustainability challenges. Hologenomics, the joint study of the genomic features of animals and the microbial communities associated with them, opens new avenues to obtain in-depth knowledge on how host-microbiota interactions affect animal performance and welfare, and in doing so, improve the quality and sustainability of animal production. Here, we introduce the animal trials conducted with broiler chickens in the H2020 project HoloFood, and our strategy to implement hologenomic analyses in light of the initial results, which despite yielding negligible effects of tested feed additives, provide relevant information to understand how host genomic features, microbiota development dynamics and host-microbiota interactions shape animal welfare and performance. We report the most relevant results, propose hypotheses to explain the observed patterns, and outline how these questions will be addressed through the generation and analysis of animal-microbiota multi-omic data during the HoloFood project.
