A flavone-polysaccharide based prescription attenuates the mitochondrial dysfunction induced by duck hepatitis A virus type 1

Tianjihuang compound alleviates aflatoxin B1-induced hepatic steatosis and fibrosis by targeting PPARα-TGF-β pathway in ducklings

Aflatoxin B1 (AFB1), a potent mycotoxin, poses a significant threat to the poultry industry, particularly affecting the health and growth of ducklings. The present study aimed to investigate the therapeutic effects and mechanisms of the Tianjihuang compound (HRS), a traditional Chinese medicine formulation, on AFB1-induced chronic toxicity in ducklings. Firstly, 30 ingredients, including neochlorogenic acid, kaempferol 3-alpha-D-galactoside, quercetin, hispidulin, caffeic acid, and myricetin, were identified from HRS with UPLC-MS/MS method. Then, over a 25-day experimental period, a total of 100 one-day-old Sichuan Sheldrakes were randomly divided into five groups: control, AFB1 model, and HRS high (4 g/kg), medium (2 g/kg), and low dosage (1 g/kg) groups. Results indicated that HRS effectively mitigated the negative impact on the productivity, reduced the levels of liver index, AST, ALT, and AST/ALT in serum, increased the levels of serum TP content, and obviously alleviated inflammatory cell infiltration, liver fibrosis, and liver steatosis induced by AFB1. Additionally, HRS enhanced the levels of GST, CAT, and T-AOC, and decreased the levels of MDA and AFB1-DNA, thereby alleviating oxidative stress and AFB1-DNA generation caused by AFB1. Transcriptome analysis revealed that HRS may improve liver injury in AFB1-chronically poisoned ducklings by regulating the ECM receptor interaction, fatty acid metabolism, cell adhesion molecules, TGF-β signaling pathway, and PPAR signaling pathway. Further RT-qPCR analysis revealed that HRS might downregulate the expression of ASCL4 gene by promoting the activation of PPARα, thereby inhibiting the activation of the TGF-β signaling pathway and improving liver steatosis and fibrosis caused by AFB1 in ducklings. In conclusion, the HRS exhibits hepatoprotective effects against AFB1-induced chronic toxicity in ducklings by restoring liver function, enhancing antioxidant capacity, and its mechanism of damage resistance may be related to the improvement of liver steatosis and fibrosis in ducklings by inhibiting the PPARα-TGF-β signaling pathway.

Radix Isatidis polysaccharide (RIP) alleviates QX-genotype infectious bronchitis virus-induced interstitial nephritis through the Nrf2/NLRP3/Caspase-3 signaling pathway

Interstitial nephritis is the primary cause of mortality in IBV-infected chickens. Our previous research has demonstrated that Radix Isatidis polysaccharide (RIP) could alleviate this form of interstitial nephritis. To explore the mechanism, SPF chickens and chicken embryonic kidney cells (CEKs) were pre-treated with RIP and subsequently infected with QX-genotype IBV strain. Kidneys were sampled for transcriptomic and metabolomic analyses, and the cecum contents were collected for 16S rRNA gene sequencing. Results showed that pre-treatment with RIP led to a 50 % morbidity reduction in infected-chickens, along with decreased tissue lesion and viral load in the kidneys. Multi-omics analysis indicated three possible pathways (including antioxidant, anti-inflammatory and anti-apoptosis) which associated with RIP's efficacy against interstitial nephritis. Following further validation both in vivo and in vitro, the results showed that pre-treatment with RIP could activate the antioxidant transcription factor Nrf2, stimulate antioxidant enzyme expression, and consequently inhibit oxidative stress. Pre-treatment with RIP could also significantly reduce the expression of NLRP3 inflammasome and apoptosis-associated proteins (including Bax, Caspase-3, and Caspase-9). Additionally, RIP was also observed to promote the growth of beneficial bacteria in the intestine. Overall, pretreatment with RIP can alleviate QX-genotype IBV-induced interstitial nephritis via the Nrf2/NLRP3/Caspase-3 signaling pathway. This study lays the groundwork for the potential use of RIP in controlling avian infectious bronchitis (IB).

Anti-virus activity and mechanisms of natural polysaccharides from medicinal herbs

There has been a sudden increase in viral diseases, such as coronavirus disease 2019 (COVID-19), causing significant harm to human and animal well-being, as well as economic development. Medicinal herbs, with a history of thousands of years in clinical use, contain versatile polysaccharides as one of their primary compounds. This review offers an overview of the antiviral effects of polysaccharides from medicinal herbs on viruses in humans, poultry, swine and aquaculture in recent years. The mechanism of these antiviral polysaccharides, involved in hindering various stages of the viral life cycle thereby blocking virus infection, is summarized. The review also explores other underlying mechanisms of antiviral effects, such as enhancing the immune response, regulating inflammatory reactions, balancing gut flora, reducing oxidative stress, and suppressing apoptosis through various corresponding signaling pathways. The structure-function relationships discussed in this article also aid in understanding the antiviral mechanism of natural polysaccharides, indicating the need for more in-depth research and analysis. Natural polysaccharides from medicinal herbs have emerged as valuable resources in the fight against viral infections, exhibiting high effectiveness. This review emphasizes the promising role of polysaccharides from medicinal herbs as potential candidates for blocking viral infections in humans and animals.

Development of hepatic steatosis in male and female mule ducks after respective force-feeding programs

Male and female mule ducks were subjected to a force-feeding diet to induce liver steatosis as it is generally done only with male ducks for the production of foie gras. The different biochemical measurements indicated that the course of hepatic steatosis development was present in both sexes and associated with a huge increase in liver weight mainly due to the synthesis and accumulation of lipids in hepatocytes. In livers of male and female ducks, this lipid accumulation was associated with oxidative stress and hypoxia. However, certain specific modifications (kinetics of lipid droplet development and hepatic inflammation) indicate that female ducks may tolerate force-feeding less well, at least at the hepatic level. This is in contradiction with what is generally reported concerning hepatic steatosis induced by dietary disturbances in mammals but could be explained by the very specific conditions imposed by force-feeding. Despite this, force-feeding female ducks seems entirely feasible, provided that the final quality of the product is as good as that of the male ducks, which will remain to be demonstrated in future studies.

Evolution of oxidative stress markers in livers of ducks during force-feeding

Mule ducks have been force-fed to develop a hepatic steatosis, also called "foie gras", which is similar to the non-alcoholic fatty liver disease (NAFLD) described in humans and mammals. However, in hepatic steatosis resulting from force-feeding of ducks, very little is known about the fine biochemical events that occur due to the enormous and very rapid increase in total lipids that mainly accumulate in hepatocytes. To begin to reduce this lack of knowledge associated with the development of this specific hepatic steatosis, liver samples were taken at different times to follow the overall biochemical transformation of the liver as well as different markers of oxidative stress, hypoxia and apoptosis. The results indicate that the lipid content increases rapidly in the liver throughout the force-feeding period while the protein content decreases. The amount of hydroxyproline remains constant indicating that no liver fibrosis develops during the force-feeding period. On the contrary, all the tested biomarkers of cellular oxidative stress increase rapidly but without any visible disorder in the coordination of paired activities. At the same time, hypoxia-inducible factors also increase indicating that a hypoxia situation is gradually occurring in hepatocytes. This leads, in addition to the lipotoxicity induced by the accumulation of lipids, to an increased number of liver cells to enter into apoptosis. A relative variability in the level of these cellular responses was also observed indicating that, probably, certain animals support the development of this steatosis differently. This leads us to imagine that the physiological status of these birds may differ widely for reasons that remain to be clarified.

Mutations in VP0 and 2C Proteins of Duck Hepatitis A Virus Type 3 Attenuate Viral Infection and Virulence

Duck hepatitis A virus (DHAV) is prevalent worldwide and has caused significant economic losses. As the predominant serotype in China, DHAV-3 has become a major challenge to the local duck industry. Here the genetics and pathogenesis of a virulent DHAV-3 strain and its embryo-passaged strain were assessed. There were only two amino acid substitutions (Y164N in VP0 protein and L71I in 2C protein) introduced during the adaptation process. The pathogenicity of these strains was further evaluated in vivo. Clinical signs, gross pathology, and histopathological analysis showed that the embryo-passaged strain was attenuated. Meanwhile, the viral RNA loads were significantly lower in the liver tissues of the ducklings infected with the attenuated strain. As expected, infection with the virulent and attenuated strains led to the activation of different innate immune genes. We suspected that the loss of replication efficiency in ducklings was responsible for the attenuation phenotype of the embryo-passaged strain. In addition, different innate immune responses in the liver of ducklings were at least partly responsible for the differential infectivity phenotype. These findings provide new insights into the genetics and pathogenesis of DHAV-3, which may aid the development of new vaccines and the implementation of immunization strategies.

LC-MSn and HR-MS characterization of secondary metabolites from Hypericum japonicum Thunb. ex Murray from Nepalese Himalayan region and assessment of cytotoxic effect and inhibition of NF-κB and AP-1 transcription factors in vitro

Hypericum japonicum Thunb. ex Murray is traditionally used in Nepal to treat several diseases, among whom inflammation and acute pain. Although several secondary metabolites from the same Hypericum species have been already characterized and considered for their pharmacological use, an exhaustive phytochemical characterization of H. japonicum from Nepal is lacking, as well as the assessment of its potential pharmacological properties. Hence, the aims of this study were the characterization of a methanolic extract of H. japonicum (HJME) collected from the Northern region of Nepal by LC-MSⁿ and UPLC-QTOF. The assessment of in vitro inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activator protein 1 (AP-1) transcription factors and HJME's cytotoxic effect on human cell lines was performed to evaluate the potential use of this herb as a source of anti-inflammatory and cytotoxic lead compounds. Fifty-seven phytoconstituents were identified, being mainly flavonoids, phloroglucinols, phenolic acids and xanthones. Although compounds characteristic of H. japonicum were detected (quercetin, quercetin-7-O-α-l-rhamnoside, quercitrin and hyperoside), several others are here reported for the first time in this species. The results from bioassays indicated that HJME could significantly reduce the viability of human THP-1 cells (IC₅₀ = 5.4 ± 1.1 μg mL^-1), showing the promising potential of HJME as anti-tumor agent. Furthermore, HJME significantly decreased the activation of both NF-κB and AP-1 at the concentration of 2 μg mL^-1. Overall, these data suggest that H. japonicum from Nepal could be used as a source of potential natural anti-inflammatory and anti-tumor lead compounds.

Transcriptomic Characterization of a Chicken Embryo Model Infected With Duck Hepatitis A Virus Type 1

Duck hepatitis A virus type 1 (DHAV-1) is one of the most common and lethal pathogens in young ducklings. Live-attenuated DHAV vaccine (CH60 strain) developed by passaging in chicken embryos provided effective immune protection for ducklings. However, the accurate mechanism for such adaption in chicken embryos is not fully revealed. Here, we utilize RNA-sequencing to perform global transcriptional analysis of DHAV-1-innoculated embryonated livers along with histopathological and ultrastructural analysis. This study revealed that infection with DHAV-1 strain CH60 is associated with enhanced type I and II interferon responses, activated innate immune responses, elevated levels of suppressor of cytokine signaling 1 and 3 (SOCS1 and SOCS3) accompanied with abnormalities in multiple metabolic pathways. Excessive inflammatory and innate immune responses induced by the CH60 strain are related to severe liver damage. Our study presents a comprehensive characterization of the transcriptome of chicken embryos infected with DHAV-CH60 and provides insight for in-depth exploration of viral adaption and virus-host interactions.