Astragaloside-IV promotes autophagy via the Akt/mTOR pathway to improve cellular lipid deposition.

The current study aimed to investigate the potential role of astragaloside IV (AS-IV) in improving cellular lipid deposition and its underlying mechanism. A fatty liver cell model was established by treating hepatoma cells with palmitic acid. AS-IV and SC79 were used for treatment. Oil Red O staining was applied to detect intracellular lipid deposition, and transmission electron microscopy was utilized to assess autophagosome formation. Immunofluorescence double staining was applied to determine microtubule-associated proteins 1A/1B light chain 3 (LC3) expression. Western blot analysis was performed to detect the expression of LC3, prostacyclin, Beclin-1, V-akt murine thymoma viral oncogene homolog (Akt), phosphorylated Akt, mTOR, and phosphorylated mTOR. Oil Red O staining revealed that AS-IV reduced intracellular lipid accumulation. Further, it increased autophagosome synthesis and the expression of autophagy proteins LC3 and Beclin-1 in the cells. It also reduced the phosphorylation levels of Akt and mTOR and the levels of prostacyclin. However, the effects of AS-IV decreased with SC79 treatment. In addition, LC3B + BODIPY493/503 fluorescence double staining showed that AS-IV reduced intracellular lipid deposition levels by enhancing autophagy. AS-IV can reduce lipid aggregation in fatty liver cells, which can be related to enhanced hepatocyte autophagy by inhibiting the Akt/mTOR signaling pathway.

Deposition and enrichment of carotenoids in livestock products: An overview.

A wide range of research has illustrated that carotenoids play a key role in human health through their versatile beneficial biological functions. Traditionally, the majority dietary sources of carotenoids for humans are obtained from vegetables and fruits, however, the contribution of animal-derived foods has attracted more interest in recent years. Livestock products such as eggs, meat, and milk have been considered as the appropriate and unique carriers for the deposition of carotenoids. In addition, with the enrichment of carotenoids, the nutritional quality of these animal-origin foods would be improved as well as the economic value. Here, we offer an overview covering aspects including the physicochemical properties of carotenoids, the situation of carotenoids fortified in livestock products, and the pathways that lead to the deposition of carotenoids in livestock products. The summary of these important nutrients in livestock products will provide references for animal husbandry and human health.

Deposition and bioconversion law of ß-carotene in laying hens after long-term supplementation under adequate vitamin A status in the diet.

ß-Carotene, because it is the precursor of vitamin A and has versatile biological roles, has been applied as a feed additive in the poultry industry for a long time. In this study, we investigated the deposition and bioconversion of ß-carotene in laying hens. A total of 600 Hy-line brown laying hens at 40 wk of age were randomly divided into 5 dietary treatments, each group's dietary supplemental levels of ß-carotene were 0, 15, 30, 60, 120 mg/kg feed, and the vitamin A levels were all 8,000 IU/kg. After 14-wk trial, samples were collected, then carotenoids and different forms of vitamin A were detected using the novel method developed by our laboratory. We found that dietary ß-carotene treatment had no significant effects on laying hens' production performance and egg quality (P > 0.05), except the yolk color. The deposition of ß-carotene in the body gradually increased (P < 0.01) with the supplemental dose, whereas the contents of lutein and zeaxanthin decreased (P < 0.05). When the ß-carotene supplemental level was above 30 mg/kg in the diet, the different forms of vitamin A in in serum, liver, ovary, and yolks were increased compared to the control group (P < 0.05). However, these indicators decreased when the additional dose was 120 mg/kg. Moreover, the mRNA levels of the genes involved in ß-carotene absorption, bioconversion, and negative feedback regulation in duodenal mucosa and liver were upregulated after long-term feeding (P < 0.05). Histological staining of the ovaries indicated that the deposition of ß-carotene led to a lower rate of follicle atresia (P < 0.05), and this positive effects may be related to the antioxidant function of ß-carotene, which caused a reduction of oxidation products in the ovary (P < 0.05). Altogether, ß-carotene could accumulate in laying hens intactly and exert its biological functions in tissue. Meanwhile, a part of ß-carotene could also be converted into vitamin A but this bioconversion has an upper limit and negative feedback regulation.

Development and application of a SFC-DAD-MS/MS method to determine carotenoids and vitamin A in egg yolks from laying hens supplemented with ß-carotene.

ß-Carotene, a provitamin A carotenoid, can be converted into vitamin A in animals' bodies, and can also be accumulated intactly in many animal products. In this study, supercritical fluid chromatography-tandem mass spectrometry was utilized to determine ß-carotene and different forms of vitamin A in eggs simultaneously. According to the results, ß-carotene contained in yolk reached a plateau after about 2 weeks of supplementation. With an increase in dietary supplement level, the amount of ß-carotene gradually increased, as well as slightly changing the yolk color. Moreover, the contents of retinoids including retinol, retinyl propionate, retinyl palmitate and retinyl stearate were also elevated in yolks with the ß-carotene additive levels; meanwhile, the lutein and zeaxanthin decreased. On the whole, ß-carotene in the diet of laying hens could be partially deposited in egg yolk, and the contents of vitamin A in yolk could be increased due to ß-carotene bioconversion.

Quantitative proteomics reveals tissue-specific toxic mechanisms for acute hydrogen sulfide-induced injury of diverse organs in pig.

Hydrogen sulfide (H2S) is a highly toxic gas in many environmental and occupational places. It can induce multiple organ injuries particularly in lung, trachea and liver, but the relevant mechanisms remain poorly understood. In this study, we used a TMT-based discovery proteomics to identify key proteins and correlated molecular pathways involved in the pathogenesis of acute H2S-induced toxicity in porcine lung, trachea and liver tissues. Pigs were subjected to acute inhalation exposure of up to 250 ppm of H2S for 5 h for the first time. Changes in hematology and biochemical indexes, serum inflammatory cytokines and histopathology demonstrated that acute H2S exposure induced organs inflammatory injury and dysfunction in the porcine lung, trachea and liver. The proteomic data showed 51, 99 and 84 proteins that were significantly altered in lung, trachea and liver, respectively. Gene ontology (GO) annotation, KEGG pathway and protein-protein interaction (PPI) network analysis revealed that acute H2S exposure affected the three organs via different mechanisms that were relatively similar between lung and trachea. Further analysis showed that acute H2S exposure caused inflammatory damages in the porcine lung and trachea through activating complement and coagulation cascades, and regulating the hyaluronan metabolic process. Whereas antigen presentation was found in the lung but oxidative stress and cell apoptosis was observed exclusively in the trachea. In the liver, an induced dysfunction was associated with protein processing in the endoplasmic reticulum and lipid metabolism. Further validation of some H2S responsive proteins using western blotting indicated that our proteomics data were highly reliable. Collectively, these findings provide insight into toxic molecular mechanisms that could potentially be targeted for therapeutic intervention for acute H2S intoxication.

Effects of acute heat stress at different ambient temperature on hepatic redox status in broilers.

This study aimed to investigate the effects of different acute high ambient temperatures on redox status in liver of broilers. A total of 144 35-day-old Arbor Acres broilers were randomly divided into 4 groups with 6 replicates of 6 birds each and subsequently distributed in different environment chambers for acute heat stress. The temperature of 4 environment chambers were set to 26°C (control), 29°C, 32°C, 35°C for 6 h, respectively. Various indicators were tested to evaluate hepatic redox status. Then, the hallmarks of hepatocellular antioxidant and apoptosis were measured by qRT-PCR and Western Blot. The results showed that with the ambient temperature increase (i) the content of hydrogen peroxide (H2O2) and protein carbonyl (PC) in the liver of broilers increased significantly (P < 0.05), but the content of malondialdehyde (MDA) and 8-hydroxyguanosine (8-OHdG) was not affected; (ii) the activity of catalase (CAT) and glutathione reductase (GR) increased significantly (P < 0.05). Similarly, the superoxide dismutase (SOD) had an increasing tendency (P = 0.07), and the content of the reduced glutathione (GSH) was also significantly increased (P < 0.05) under high temperature; (iii) the heat shock protein (HSP70), nuclear factor erythroid-2-related factor 2 (Nrf2), and other antioxidant gene (HO-1, NQO1, GCLc, GST, SOD1, SOD2, CAT, Prx3) were upregulated in broilers liver. Moreover, the protein level of HSP70, Nrf2, and Prx3 were also upregulated; (iv) high temperature upregulated the antiapoptotic gene expression (BCL-2); however, the proapoptotic genes (BAK1, caspase-3, and caspase-9) did not change significantly; meanwhile, there was no significant changes in the protein level of caspase-3 and caspase-9. The results of this study indicated that 35-day-old Arbor Acres broilers have a certain tolerance to oxidative stress induced by high ambient temperature. Six hours of acute heat stress-activated Nrf2 signaling pathway. Meanwhile, the expression of related antioxidant genes and proteins is upregulated, consequently resulted in increased antioxidant enzymes activity and GSH. These effects enable the body to scavenge large amounts of reactive oxygen species produced by high temperature and prevent the occurrence of apoptosis.