Abstract
BackgroundThe ureagenesis plays a central role in the homeostatic control of nitrogen metabolism. This process occurs in the liver, the key metabolic organ in the maintenance of energy homeostasis in the body. To date, the understanding of the influencing factors and regulators of ureagenesis in ruminants is still poor. The aim of this study was to investigate the relationship between energy metabolism and ureagenesis and detect the direct regulators of ureagenesis in the liver by using RNA-seq technology.ResultsEighteen four-month-old male goats were divided into two groups randomly and received a diet containing 10% (LNFC group, n = 9) or 30% non-fiber carbohydrate (MNFC group, n = 9), respectively, for four weeks. The global gene expression analysis of liver samples showed that, compared with a LNFC diet, the MNFC diet promoted the expression of genes required for synthesis of fatty acid and glycerol, whereas it suppressed those related to fatty acid oxidation, gluconeogenesis from amino acids and ureagenesis. Additionally, gene expression for rate-limiting enzymes of ureagenesis were highly correlated to the gene expression of key enzymes of both fatty acid synthesis and glycerol synthesis (Spearman correlation coefficient > 0.8 and p < 0.05). In the differentially expressed signaling pathways related to the endocrine system, the MNFC diet activated the insulin and PPAR signaling pathway, whereas it suppressed the leptin-JAK/STAT signaling pathway, compared with the LNFC diet. Reverse transcription quantitative PCR analyses of 40 differentially expressed genes confirmed the RNA-seq results (R2 = 0.78).ConclusionOur study indicated that a dietary NFC-induced increase of energy supply promoted lipid anabolism and decreased ureagenesis in the caprine liver. By combining our results with previously published reports, insulin signaling can be suggested to play the dominant role in the coordinated control of hepatic energy metabolism and ureagenesis.
Highlights
The ureagenesis plays a central role in the homeostatic control of nitrogen metabolism
Differences of ruminal short-chain fatty acids (SCFAs) concentrations among groups Compared with the goats fed with a diet containing 10% non-fiber carbohydrate (NFC) (LNFC group), the concentrations of ruminal butyrate, propionate, and total SCFAs were significantly increased, whereas ruminal pH was significantly decreased in the goats fed with a diet containing 30% NFC (MNFC group)
Systematic cluster analysis showed that the 18 samples were categorized into two clusters according to the ratio of dietary NFC received by the goats (Additional file 3)
Summary
The ureagenesis plays a central role in the homeostatic control of nitrogen metabolism. This process occurs in the liver, the key metabolic organ in the maintenance of energy homeostasis in the body. The understanding of the influencing factors and regulators of ureagenesis in ruminants is still poor. The aim of this study was to investigate the relationship between energy metabolism and ureagenesis and detect the direct regulators of ureagenesis in the liver by using RNA-seq technology. Hepatic infusion studies have shown that an increase of ammonia or AA content promotes LSU in sheep [2]. Whether endocrine regulation in ruminants is similar to that of monogastric animals has not been studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
