Biological Effects and Applications of Chitosan and Chito-Oligosaccharides

The numerous functional properties and biological effects of chitosan and chito-oligosaccharides (COS) have led to a significant level of interest, particularly with regard to their potential use in the agricultural, environmental, nutritional, and pharmaceutical fields. This review covers recent studies on the biological functions of COS and the impacts of dietary chitosan and COS on metabolism. The majority of results suggest that the use of chitosan as a feed additive has favorable biological effects, such as antimicrobial, anti-oxidative, cholesterol reducing, and immunomodulatory effects. The biological impacts reviewed herein may provide a new appreciation for the future use of COS

Chitosan Modulates Inflammatory Responses in Rats Infected with Enterotoxigenic Escherichia coli

This study aims to investigate the effects of dietary chitosan (COS) on gastrointestinal pathogen resistance in mice model. For two weeks, a control group of ICR mice received a basal diet whilst the intervention group received the basal diet supplemented with 300 mg/kg COS. After two weeks, the mice fed the supplemented diet had a lower body weight. Then enterotoxigenic Escherichia coli (E. coli) was administered to the mice through oral gavage, with each mouse receiving 108 CFU. At day 7 after infection, the bacterial load in the jejunum and faeces was significantly lower in the COS group than that in the control group. Moreover, the mRNA and protein levels of IL-1β, IL-6, IL-17, IL-18, and TNF-α were significantly lower in the group of mice receiving the COS diet; also the jejunal production of toll-like receptor-4 (TLR-4) was suppressed in the COS group. These results indicate the intervention influenced inflammation and controlled E. coli infection

Implications of Antioxidant Systems in Inflammatory Bowel Disease

The global incidence of inflammatory bowel disease (IBD), a group of chronic gastrointestinal disorders, has been rising. The preponderance of evidence demonstrates that oxidative stress (OS) performs a critical function in the onset of IBD and the manner of its development. The purpose of this review is to outline the generation of reactive oxygen species and antioxidant defense mechanisms in the gastrointestinal tract and the role played by OS in marking the onset and development of IBD. Furthermore, the review demonstrates the various ways through which OS is related to genetic susceptibility and the mucosal immune response. The experimental results suggest that certain therapeutic regimens for IBD could have a favorable impact by scavenging free radicals, reducing cytokine and prooxidative enzyme concentrations, and improving the antioxidative capabilities of cells. However, antioxidative activity characterized by a high level of specificity may be fundamental for the development of clinical therapies and for relapsing IBD patients. Therefore, additional research is required to clarify the ways through which OS is related to the pathogenesis and progression of IBD

Low Dosage of Chitosan Supplementation Improves Intestinal Permeability and Impairs Barrier Function in Mice

The purpose of this study was to explore relationships between low dose dietary supplementation with chitosan (COS) and body weight, feed intake, intestinal barrier function, and permeability in mice. Twenty mice were randomly assigned to receive an unadulterated control diet (control group) or a dietary supplementation with 30 mg/kg dose of chitosan (COS group) for two weeks. Whilst no significant differences were found between the conditions for body weight or food and water intake, mice in the COS group had an increased serum D-lactate content (P<0.05) and a decreased jejunal diamine oxidase (DAO) activity (P<0.05). Furthermore, mice in COS group displayed a reduced expression of occludin and ZO-1 (P<0.05) and a reduced expression of occludin in the ileum (P<0.05). The conclusion drawn from these findings showed that although 30 mg/kg COS-supplemented diet had no effect on body weight or feed intake in mice, this dosage may compromise intestinal barrier function and permeability. This research will contribute to the guidance on COS supplements

Antioxidant and Anti-Inflammatory Effects of Different Zinc Sources on Diquat-Induced Oxidant Stress in a Piglet Model

Zinc (Zn) plays a crucial role in reducing oxidative stress and diarrhea in postweanling piglets. This study is aimed at comparing the effects of zinc chelate of 2-hydroxy-4 methyl-thio butanoic acid (HMZn) and ZnSO4 on the oxidative stress in weaned piglets. A total of 32 piglets were randomly divided into 4 treatments: CON: basal diet+80 mg/kg Zn as ZnSO4; DIQ: basal diet+80 mg/kg Zn as ZnSO4; HMZn: basal diet+200 mg/kg Zn as HMZn; and ZnSO4: basal diet+200 mg/kg Zn as ZnSO4. On day 15, the DIQ, HMZn, and ZnSO4 groups were injected intraperitoneally with diquat except for the CON group. The trial lasted 21 days. The results showed that zinc sources did not influence the growth performance during the first 14 days. But HMZn increased activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and total antioxidant capacity (T-AOC) in serum (P<0.05). After diquat injection, the fecal score was decreased in the HMZn group. Both HMZn and ZnSO4 increased the activities of GPX and T-AOC in serum and the relative mRNA expressions of hepatic and renal Nrf2, SOD1, and GPX compared with the DIQ group (P<0.05). Moreover, the relative mRNA expression of inflammatory factors in the small intestine, liver, and kidney was downregulated; the phosphorylation of NF-κB protein was inhibited in the HMZn group compared with the DIQ and ZnSO4 groups (P<0.05). In general, HMZn showed notable advantage over ZnSO4 in reducing diarrhea and improving antioxidant and anti-inflammatory ability in piglets challenged with diquat

Dietary Serine Supplementation Improves Growth Performance, Intramuscular Fat Content, and Composition of Gut Microbes and Metabolites in Growing–Finishing Pigs

Serine is widely involved in antioxidant synthesis, immune response, and fat metabolism. However, it remains unclear whether dietary serine supplementation affects fat deposition in the skeletal muscles of pigs. Thus, we explored the effects of dietary serine supplementation on growth performance, meat quality, and composition of gut microbes and their metabolites in growing–finishing pigs. Forty-eight boars weighing approximately 20 kg were fed either a basal diet or a basal diet supplemented with 0.15% serine. The results showed that dietary serine increased the daily weight gain of pigs and improved serum antioxidant capacity as indicated by the decreased malondialdehyde content and increased glutathione and superoxide dismutase content. Pigs supplemented with serine had better meat quality, as shown by the lower drip loss and higher IMF content. Furthermore, dietary serine increased the relative abundance of Streptococcus and Lactobacillus and decreased the relative abundance of Clostridium_sensu_stricto_1 and Terrisporobacter. Differential microbial metabolites were mostly enriched in metabolic pathways related to lipid synthesis, such as alpha-linolenic acid metabolism and steroid hormone biosynthesis. Correlation analysis showed that the altered metabolites were closely related to the intestinal microbiota. In conclusion, our results suggested that serine serves as a potential additive for improving IMF content in growing–finishing pigs

N-Acetyl-L-cysteine Protects the Enterocyte against Oxidative Damage by Modulation of Mitochondrial Function

The neonatal small intestine is susceptible to damage caused by oxidative stress. This study aimed to evaluate the protective role of antioxidant N-acetylcysteine (NAC) in intestinal epithelial cells against oxidative damage induced by H2O2. IPEC-J2 cells were cultured in DMEM-H with NAC and H2O2. After 2-day incubation, IPEC-J2 cells were collected for analysis of DNA synthesis, antioxidation capacity, mitochondrial respiration, and cell apoptosis. The results showed that H2O2 significantly decreased (P<0.05) proliferation rate, mitochondrial respiration, and antioxidation capacity and increased cell apoptosis and the abundance of associated proteins, including cytochrome C, Bcl-XL, cleaved caspase-3, and total caspase-3. NAC supplementation remarkably increased (P<0.05) proliferation rate, antioxidation capacity, and mitochondrial bioenergetics but decreased cell apoptosis. These findings indicate that NAC might rescue the intestinal injury induced by H2O2

Responses of Field‐Aligned Currents and Equatorial Electrojet to Sudden Decrease of Solar Wind Dynamic Pressure During the March 2023 Geomagnetic Storm

Abstract We present the observations of field‐aligned currents and the equatorial electrojet during the 23 March 2023 magnetic storm, focusing on the effect of the drastic decrease of the solar wind dynamic pressure occurred during the main phase. Our observations show that the negative pressure pulse had significant impact to the magnetosphere‐ionosphere system. It weakened large‐scale field‐aligned currents and paused the progression of the storm main phase for ∼3 hr. Due to the sudden decrease of the plasma convection after the negative pressure pulse, the low‐latitude ionosphere was over‐shielded and experienced a brief period of westward penetration electric field, which reversed the direction of the equatorial electrojet. The counter electrojet was observed both in space and on the ground. A transient, localized enhancement of downward field‐aligned current was observed near dawn, consistent with the mechanism for transmitting MHD disturbances from magnetosphere to the ionosphere after the negative pressure pulse

Dietary Inclusion of a Mixed Powder of Medicinal Plant Leaves Enhances the Feed Efficiency and Immune Function in Broiler Chickens

The trial was designed to determine the effect of the mixed powder of leaves of Anacardium occidentale (60%), Psidium guajava (20%), and Morinda citrifolia (20%) on growth performance, nutrient digestibility, and immunoglobulin concentration in broiler chickens. A total of 80 one-day-old Ross 308 broiler chickens were randomly assigned to two dietary treatments from days 1 to 21 of age, with 8 replicates by treatments and 5 birds per replicate. Treatments consisted of a control diet (T0) and the dietary inclusion of 0.5% of mixed powder of medicinal plant leaves (T1). The inclusion of herbs decreases the feed intake (FI) and feed conversion ratio (FCR; P0.05) on nutrient digestibility and IgA concentration; however, the IgG concentration increased by the effect of this experimental treatment. The results allow recommending the dietary inclusion of mixed powder of medicinal plant leaves as an alternative for obtaining acceptable performance in broilers