The effect of dietary asparagine supplementation on energy metabolism in liver of weaning pigs when challenged with lipopolysaccharide

Development and Recovery of Liver Injury in Piglets by Incremental Injection of LPS

This study aimed to explore the effects of the incremental injection of lipopolysaccharide (LPS) on liver histopathology, inflammation, oxidative status, and mitochondrial function in piglets. Forty healthy Duroc × Landrace × Yorkshire castrated boars (21 ± 2 days old, weight 6.84 ± 0.11 kg) were randomly assigned to five groups (n = 8) and then slaughtered on days 0 (group 0, without LPS injection), 1 (group 1), 5 (group 5), 9 (group 9), and 15 (group 15) of LPS injection, respectively. The results showed that, compared to the piglets without LPS injection, LPS injection caused liver injury in the early phase, as manifested by the increased activities of serum liver injury-related parameters (aspartate amino transferase, alanine aminotransferase, alkaline phosphatase, cholinesterase, and total bile acid) on day 1, and impaired liver morphology (disordered hepatic cell cord arrangement, dissolved and vacuolized hepatocytes, karyopycnosis, and inflammatory cell infiltration and congestion) on days 1 and 5. Meanwhile, LPS injection caused liver inflammation, oxidative stress, and mitochondrial dysfunction on days 1 and 5, as reflected by the upregulated mRNA expression of TNF-α, IL-6, IL-1β, TLR4, MyD88, and NF-κB; increased MPO and MDA content; and impaired mitochondrial morphology. However, these parameters were ameliorated in the later phase (days 9~15). Taken together, our data indicate that the incremental injection of the LPS-induced liver injury of piglets could be self-repaired.

Dietary Isoleucine and Valine: Effects on Lipid Metabolism and Ureagenesis in Pigs Fed with Protein Restricted Diets

A mixture of valine (Val) and isoleucine (Ile) not only decreases the negative impact of very low protein (VLP) diets on the growth of pigs, but also influences the nitrogen (N) balance and lipid metabolism; however, the underlying pathways are not well understood. This study aimed to investigate the effect of dietary Val and Ile on lipogenesis, lipolysis, and ureagenesis under protein restriction. After one week of acclimation, forty three-week-old pigs were randomly assigned to following dietary treatments (n = 8/group) for 5 weeks: positive control (PC): normal protein diet; negative control (NC): VLP diet; HV: NC supplemented with Val; HI: NC supplemented with Ile; and HVI: NC supplemented with both Val and Ile. HVI partially improved the body weight and completely recovered the feed intake (FI) of pigs fed with NC. HVI increased thermal radiation and improved the glucose clearance. HVI had a lower blood triglyceride than PC and blood urea N than NC. NC and HV promoted lipogenesis by increasing the transcript of fatty acid synthase (FAS) in the liver and lipoprotein lipase (LPL) in adipose tissue but reducing hormone-sensitive lipase (HSL) in the liver. HVI reduced the increased rate of lipogenesis induced by the NC group through normalizing the mRNA abundance of hepatic FAS, sterol regulatory element binding transcription factor 1, and HSL and LPL in adipose tissue. NC, HV, HI, and HVI reduced the ureagenesis by decreasing the protein abundance of carbamoyl phosphate synthetase I, ornithine transcarboxylase, and arginosuccinate lyase in the liver. Overall, HVI improved the growth, FI, and glucose clearance, and decreased the rate of lipogenesis induced by VLP diets.

Biomolecular modifications in the sacfry of Mogurnda adspersa in response to copper stress

Copper (Cu) is one of the most harmful contaminants in fresh-water systems. Fish larvae such as sacfry are particularly vulnerable to metals such as copper (Cu) due to a less-developed excretory organ system and permeable skin that can absorb metals directly from the water. However, the sublethal effects of metals on this life stage are not well understood. This study assessed the sublethal toxicity of Cu on purple-spotted gudgeon sacfry (PSG, Mogurnda adspersa). For this purpose, 96 h Cu toxicity bioassays were performed and toxic effects of Cu on PSG were measured at different levels of biological organization, from the individual (loss of equilibrium, wet weight), to tissue (chemical changes in retinal tissue composition) and molecular responses (whole body amino acid (AA) profiles). The EC₁₀ and EC₅₀ (ECx: effect concentration that affected X% of test organisms) were found to be 12 (9 - 15) µg Cu L^-1 and 22 (19 - 24) µg Cu L^-1, respectively. Copper stress caused a decrease in total amino acid content and changed the AA profile of PSG compared to the controls. Proton-induced X-ray emission (PIXE) mapping techniques showed accumulation of Cu in the retinal tissues disturbing the distribution of other elements such as zinc, sulfur, phosphorus and potassium. Fourier-transform infrared (FTIR) microspectroscopy of control and Cu treated eye tissues revealed a change in protein secondary structure in retinal tissues in response to Cu accumulation, as well as decreased levels of the molecular retinal, consistent with the degradation of rhodopsin, a key protein in the visual sensory system. This is the first study to demonstrate the multi-level responses of PSG arising from exposure to environmentally realistic Cu concentrations and suggests that AA profiling can serve as a useful tool to assess the impacts of metals on fresh-water organisms.

Oral Bacteriotherapy Reduces the Occurrence of Chronic Fatigue in COVID-19 Patients

Long COVID refers to patients with symptoms as fatigue, “brain fog,” pain, suggesting the chronic involvement of the central nervous system (CNS) in COVID-19. The supplementation with probiotic (OB) would have a positive effect on metabolic homeostasis, negatively impacting the occurrence of symptoms related to the CNS after hospital discharge. On a total of 58 patients hospitalized for COVID-19, 24 (41.4%) received OB during hospitalization (OB+) while 34 (58.6%) taken only the standard treatment (OB–). Serum metabolomic profiling of patients has been performed at both hospital acceptance (T0) and discharge (T1). Six months after discharge, fatigue perceived by participants was assessed by administrating the Fatigue Assessment Scale. 70.7% of participants reported fatigue while 29.3% were negative for such condition. The OB+ group showed a significantly lower proportion of subjects reporting fatigue than the OB– one (p < 0.01). Furthermore, OB+ subjects were characterized by significantly increased concentrations of serum Arginine, Asparagine, Lactate opposite to lower levels of 3-Hydroxyisobutirate than those not treated with probiotics. Our results strongly suggest that in COVID-19, the administration of probiotics during hospitalization may prevent the development of chronic fatigue by impacting key metabolites involved in the utilization of glucose as well as in energy pathways.

Glycine alleviated diquat-induced hepatic injury via inhibiting ferroptosis in weaned piglets

Objective

The beneficial effects of glycine were tested in piglets with diquat-induced hepatic injury.

Methods

Thirty-two piglets were assigned by a 2 × 2 factorial experimental design including glycine supplementation and diquat challenge. After 3 weeks of feeding with a basic diet or a 1% glycine supplemented diet, piglets were challenged with diquat or saline. After 1 week later, the piglets were slaughtered and samples were collected.

Results

Our results indicated that glycine alleviated diquat induced morphological hepatic injury, decreased the activities of plasma alanine aminotransferase, aspartate aminotransferase and glutamyl transpeptidase in the piglets under diquat challenge, and increased total antioxidant capacity and antioxidative enzyme activity significantly. Adding glycine enhanced the concentrations of hepatic adenosine triphosphate and adenosine diphosphate. Transmission electron microscope observation showed that diquat induced clear hepatocytes ferroptosis and its effect could be alleviated by glycine to a certain degree. Moreover, glycine significantly affected mRNA and protein expression of ferroptosis-related signals in the liver.

Conclusion

These results demonstrated that glycine attenuated liver damage via inhibiting ferroptosis.

Dietary Tryptophan Supplementation Alters Fat and Glucose Metabolism in a Low-Birthweight Piglet Model

Low birthweight (LBW) is associated with metabolic complications, such as glucose and lipid metabolism disturbances in early life. The objective of this study was to assess: (1) the effect of dietary tryptophan (Trp) on glucose and fat metabolism in an LBW piglet model, and (2) the role peripheral 5-hydroxytryptamine type 3 (5HT3) receptors in regulating the feeding behavior in LBW piglets fed with Trp-supplemented diets. Seven-day-old piglets were assigned to 4 treatments: normal birthweight-0%Trp (NBW-T0), LBW-0%Trp (LBW-T0), LBW-0.4%Trp (LBW-T0.4), and LBW-0.8%Trp (LBW-T0.8) for 3 weeks. Compared to LBW-T0, the blood glucose was decreased in LBW-T0.8 at 60 min following the meal test, and the triglycerides were lower in LBW-T0.4 and LBW-T0.8. Relative to LBW-T0, LBW-T0.8 had a lower transcript and protein abundance of hepatic glucose transporter-2, a higher mRNA abundance of glucokinase, and a lower transcript of phosphoenolpyruvate carboxykinase. LBW-T0.4 tended to have a lower protein abundance of sodium-glucose co-transporter 1 in the jejunum. In comparison with LBW-T0, LBW-T0.4 and LBW-T0.8 had a lower transcript of hepatic acetyl-CoA carboxylase, and LBW-T0.4 had a higher transcript of 3-hydroxyacyl-CoA dehydrogenase. Blocking 5-HT3 receptors with ondansetron reduced the feed intake in all groups, with a transient effect on LBW-T0, but more persistent effect on LBW-T0.8 and NBW-T0. In conclusion, Trp supplementation reduced the hepatic lipogenesis and gluconeogenesis, but increased the glycolysis in LBW piglets. Peripheral serotonin is likely involved in the regulation of feeding behavior, particularly in LBW piglets fed diets supplemented with a higher dose of Trp.

Dietary Beta-Hydroxy Beta-Methyl Butyrate Supplementation Alleviates Liver Injury in Lipopolysaccharide-Challenged Piglets

The current study was performed to investigate whether dietary β-hydroxy-β-methylbutyrate (HMB) could regulate liver injury in a lipopolysaccharide- (LPS-) challenged piglet model and to determine the mechanisms involved. Thirty piglets (21 ± 2 days old, 5.86 ± 0.18 kg body weight) were randomly divided into the control (a basal diet, saline injection), LPS (a basal diet), or LPS+HMB (a basal diet + 0.60% HMB-Ca) group. After 15 d of treatment with LPS and/or HMB, blood and liver samples were obtained. The results showed that in LPS-injected piglets, HMB supplementation ameliorated liver histomorphological abnormalities induced by LPS challenge. Compared to the control group, the activities of serum aspartate aminotransferase and alkaline phosphatase were increased in the LPS-injected piglets (P < 0.05). The LPS challenge also downregulated the mRNA expression of L-PFK, ACO, L-CPT-1, ICDH β, and AMPKα1/2 and upregulated the mRNA expression of PCNA, caspase 3, TNF-α, TLR4, MyD88, NOD1, and NF-κB p65 (P < 0.05). However, these adverse effects of the LPS challenge were reversed by HMB supplementation (P < 0.05). These results indicate that HMB may exert protective effects against LPS-induced liver injury, and the underlying mechanisms might involve the improvement of hepatic energy metabolism via regulating AMPK signaling pathway and the reduction of liver inflammation via modulating TLR4 and NOD signaling pathways.

Holly (Ilex latifolia Thunb.) Polyphenols Extracts Alleviate Hepatic Damage by Regulating Ferroptosis Following Diquat Challenge in a Piglet Model

Background: Holly (Ilex latifolia Thunb.) polyphenols extracts (HPE) contain high amounts of polyphenols, including phenolic acids, triterpenoids, tannic acids, and so on, which have strong antioxidant function. This experiment was aimed to explore the protective effect and mechanism of HPE against hepatic injury induced by diquat.

Methods: Thirty-two weaned piglets were allotted by a 2 × 2 factorial experiment design with diet type (basal diet vs. HPE diet) and diquat challenge (saline vs. diquat). On the 21st day, piglets were injected with diquat or saline. One week later, blood samples were collected. Then all piglets were slaughtered and hepatic samples were collected.

Results: Dietary HPE supplementation improves hepatic morphology, the activities of plasma aspartate aminotransferase, alanine aminotransferase, and glutamyl transpeptidase, and enhances hepatic anti-oxidative capacity, while it regulates the expression of ferroptosis mediators (transferrin receptor protein 1, heat shock protein beta 1, solute carrier family 7 member 11, and glutathione peroxidase 4) in diquat-challenged piglets.

Conclusion: These results indicate that dietary HPE supplementation enhances hepatic morphology and function, which is involved in modulating antioxidant capacity and ferroptosis.

Discrimination of Lycium chinense and L. barbarum Based on Metabolite Analysis and Hepatoprotective Activity

Lycii Fructus is a traditional medicine used to prevent liver and kidney diseases, which commonly derives from Lycium chinense and Lycium barbarum. Here, the extracts and ethyl acetate-soluble fractions of L. chinense fruits exhibited better hepatoprotective effects than those of L. barbarum, which was likely due to differences in their composition. Therefore, GC-MS and HPLC analyses were conducted to characterize the metabolite differences between L. chinense and L. barbarum. Based on amino acid (AA) and phenolic acid (PA) profiling, 24 AAs and 9 PAs were identified in the two species. Moreover, each species exhibited unique and readily distinguishable AA and PA star graphic patterns. HPLC analysis elucidated composition differences between the ethyl acetate-soluble layers of the two compounds. Further, NMR analysis identified their chemical structures as 4-(2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl)butanoic acid and p-coumaric acid. The higher content of 4-(2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl)butanoic acid was detected in L. chinense, whereas the content of p-coumaric acid was higher in L. barbarum. Therefore, the differences in the relative contents of these two secondary metabolites in the ethyl acetate-soluble layer of Lycii Fructus could be a good marker to discriminate between L. chinense and L. barbarum.