Enhancement in humoral response against inactivated Newcastle disease vaccine in broiler chickens administered orally with plant-derived soyasaponin

Potential Immunoregulatory Mechanism of Plant Saponins: A Review

Saponins are extracted from different parts of plants such as seeds, roots, stems, and leaves and have a variety of biological activities including immunomodulatory, anti-inflammatory effects, and hypoglycemic properties. They demonstrate inherent low immunogenicity and possess the capacity to effectively regulate both the innate and adaptive immune responses. Plant saponins can promote the growth and development of the body's immune organs through a variety of signaling pathways, regulate the activity of a variety of immune cells, and increase the secretion of immune-related cytokines and antigen-specific antibodies, thereby exerting the role of immune activity. However, the chemical structure of plant saponins determines its certain hemolytic and cytotoxicity. With the development of science and technology, these disadvantages can be avoided or reduced by certain technical means. In recent years, there has been a significant surge in interest surrounding the investigation of plant saponins as immunomodulators. Consequently, the objective of this review is to thoroughly examine the immunomodulatory properties of plant saponins and elucidate their potential mechanisms, with the intention of offering a valuable point of reference for subsequent research and advancement within this domain.

Soya saponin fails to improve the antioxidation and immune function of laying hens with antibiotics treated

Soya saponin (SS) helps to improve antioxidant and immune function of body, and intestinal bacteria might play an important role here. In the present study, the co-occurring network of the ileal flora was analyzed with 50 mg/kg SS supplemented to the diet, and Romboutsia was found to have evolved into a dominant flora. In addition, the co-occurring network of the flora was changed with the combined antibiotic treated, and the unidentified-cyanobacteria developed into the dominant flora, whereas the relative abundance of Romboutsia was dropped. Dietary SS failed to elevate the relative abundance of Romboutsia with antibiotics treated, at the same time, it was not helpful for the antioxidant and immune function of laying hens. While dietary SS had a little help on the egg-laying performance. Intestinal bacteria did play a key role in the biological functions of SS on laying hens. In conclusion, SS failed to improve the antioxidation and immune function of laying hens with antibiotics treated.

Dietary soya saponin improves the lipid metabolism and intestinal health of laying hens

Soya saponin (SS) is a natural active substance of leguminous plant, which could improve lipid metabolism and regulate immune function. Intestinal flora might play a key role in the biological functions of SS. The objective of this study was to measure the effects of dietary SS on immune function, lipid metabolism, and intestinal flora of laying hens with or without antibiotic treated. The experiment was designed as a factorial arrangement of 3 dietary SS treatments × 2 antibiotic treatments. Birds were fed a basal diet (CON) or a low-SS diet (50 SS) containing 50 mg/kg SS, or a high-SS diet (500 SS) containing 500 mg/kg SS. Birds were cofed with or without antibiotics. The growth experiment lasted for 10 wk. Results showed that birds fed the 50 mg/kg SS diet tended to have lower abdominal fat rate. The gene expression of liver X receptor-α (LxR-α) in liver and serum total cholesterol (TC) were dropped, and the gene expression of acyl-CoA thioesterase 8 (ACOT8) in liver were upregulated. Compared with CON group, the levels of lysozyme, IL-10, and transforming growth factor (TGF-β) in the serum were elevated as along with gene expression of IL-10, TGF-β, and LYZ in ileum of both 50 and 500 SS group. However, the level of secretory immunoglobulin A (sIgA) and Mucin-2 in the ileum were downregulated in the 500 SS group. Additionally, Lactobacillus and Lactobacillus gasseri were the dominant bacteria in the 50 SS group, whereas the relative abundance of Lactobacillus was dropped in the 500 SS group. With combined antibiotics treatment, the α-diversity of bacteria was reduced, and the biological effects of SS were eliminated. In conclusion, the lipid metabolism, immune function, and intestinal flora of the laying hens were improved with the dietary supplementation of 50 mg/kg SS. But dietary 500 mg/kg SS had negative effects on laying hens.

Mechanism of interactions between soyasaponins and soybean 7S/11S proteins

In this study, the proteins glycinin (11S) and β-conglycinin (7S) were mixed with soyasaponin (Ssa) Ab/Bb to form a composite system. We used fluorescence and synchronous fluorescence spectra to demonstrate the changes in the surrounding environment and the structure of the proteins. Dynamic interface behavior analysis showed the possible interface behavior induced by the composite system. The interactions between Ssa and the proteins, along with the mode of action, were analyzed by molecular docking. The interactions between Ssa and soy protein increased with the change in concentration. The interactions between the two proteins were mediated by tryptophan (Trp) and primarily involved hydrogen bonds, which changed the microenvironment and loosened the protein structure. These results helped in understanding the mechanism underlying the interactions between Ssa Ab/Bb and 7S/11S. Furthermore, these results highlighted the theoretical fundamentals for the future applications of composite systems as surfactants in the food industry.

Soya saponin improves egg-laying performance and immune function of laying hens

BACKGROUND

Soya saponin (SS), an active compound in soybean meals, has been widely studied in the medical field. However, it was considered as an anti-nutritional factor in poultry diets. The objective of this experiment was to measure the effects of dietary SS using three dietary treatments on egg-laying performance and immune function of laying hens. Birds were fed a low soybean meal basal diet (CON), a low-SS diet (50 SS) containing 50 mg/kg SS, or a high-SS diet (500 SS) containing 500 mg/kg SS for 10 weeks. At the end of the 5th and 10th week of the trial, samples were collected for analysis.

RESULTS

Results showed that with 50 mg/kg SS supplementation, the egg production rate, feed conversion ratio (FCR), and eggshell quality tended to be improved. Serum follicle stimulating hormone (FSH) and Interleukin-4 (IL-4) levels were also elevated as well as the peripheral blood LPS stimulation index, the proportion of B lymphocytes, and antibody titer of bovine serum albumin (BSA). We also found that mRNA levels of follicle stimulating hormone receptor (FSHR) in ovarian, nuclear transcription factor kappa B (NF-κB), Transforming growth factor (TGF-β) and interferon γ (IFN-γ) in spleen were up-regulated at the end of the trial. Additionally, dietary 50 mg/kg SS improved the ileal flora via up-regulating the relative abundance of Lactobacillus, Romboutsia and Lactobacillus delbrueckii. Although the immune related indicators were improved with 500 mg/kg SS supplemented, it seemed to have a negative influence on the laying-performance. Specifically, serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and the ratio of IFN-γ to IL-4 were increased in the 500 SS group at the end of the trial. The mRNA levels of gonadotropin releasing hormone 1 (GnRH1) in Hypothalamus, the estrogen related receptor (ERR) in ovaries were downregulated as well as the egg production rate during the trial with 500 mg/kg SS supplemented.

CONCLUSIONS

The egg production performance was improved by dietary supplemented with 50 mg/kg SS via increasing ovarian FSHR transcription level and serum estrogen level. A beneficial shift in intestinal microflora was recorded, and the immune function of laying hens was also improved with 50 mg/kg SS supplementation. Surprisingly, the long-term supplementation of 500 mg/kg SS exerted a negative impact on the laying performance and physiological functions of the liver of laying hens.

Bridging the Gaps between Plant and Human Health: A Systematic Review of Soyasaponins

Saponins, prominent secondary plant metabolites, are recognized for their roles in plant defense and medicinal benefits. Soyasaponins, commonly derived from legumes, are a class of triterpenoid saponins that demonstrate significant potential for plant and human health applications. Previous research and reviews largely emphasize human health effects of soyasaponins. However, the biological effects of soyasaponins and their implications for plants in the context of human health have not been well-discussed. This review provides comprehensive discussions on the biological roles of soyasaponins in plant defense and rhizosphere microbial interactions; biosynthetic regulation and compound production; immunological effects and potential for therapeutics; and soyasaponin acquisition attributed to processing effects, bioavailability, and biotransformation processes based on recent soyasaponin research. Given the multifaceted biological effects elicited by soyasaponins, further research warrants an integrated approach to understand molecular mechanisms of regulations in their production as well as their applications in plant and human health.

A hierarchical emulsion system stabilized by soyasaponin emulsion droplets

Oil/water (O/W) emulsion droplets coated with soyasaponin (Ssa) were used as emulsifiers to prepare emulsions with hierarchical configurations (2.82 μm). Ssa is a natural triterpenoid with amphiphilic properties and an excellent emulsifying activity. Stable O/W emulsions were prepared and characterized using an ultrasonic method at a Ssa concentration of 2.5 wt%. The resultant hierarchical emulsions were further prepared using O/W droplets as emulsifiers. It was observed that the stability of the hierarchical emulsions changed with alterations to the ratio of O/W droplets to the oil phase. As the number of droplets increased, the more the surface area of the hierarchical emulsion was covered. Additional observations included a decreased particle size, increased negative charge and viscoelastic behavior, and enhanced emulsion stability. The emulsion was most stable when the O/W droplet addition was 29%. The addition of O/W droplets continued to increase, and there was an imbalance in the ratio of O/W droplets to the oil phase; the excess O/W droplets induced instability in the emulsion, resulting in a degradation of the emulsion quality. We monitored hierarchical emulsions with different concentrations of emulsifiers for 30 days, and the results indicated that hierarchical emulsions could meet the demand for long-term storage. This provides a new theoretical basis for the construction and application of complex emulsion systems.

Comparative Study of Protection against Newcastle Disease in Young Broilers Administered Natural Chicken Alpha Interferon via Oral and Intramuscular Routes

Newcastle disease (ND) is an economically important contagious disease of wild and domestic birds worldwide. The disease causes severe economic losses in terms of production due to high mortality and morbidity in nonvaccinated chickens. Despite extensive vaccination approaches, Newcastle disease (ND) remains a permanent threat to the poultry industry worldwide. In the current study, we used natural chicken IFN-α as an innate immune modulator to counteract ND in chickens. We report that chIFN-α is effective in protecting the chickens against ND and also prevents shedding of the virus, which can then prevent further spread of the disease. We propose that in addition to vaccination, chIFN-α therapy could be an effective option for controlling ND in areas of endemicity.

Despite extensive vaccination approaches, Newcastle disease (ND) remains a permanent threat to the poultry industry worldwide. Besides vaccination, there is a burgeoning demand for new antivirals for use in interventions to control ND. One strategy is to strengthen the host innate immunity via host-derived innate immune proteins. Type I interferons define one of the first lines of innate immune defense against viral infections. Chicken interferon alpha (chIFN-α) is one of the potent cytokines that trigger antiviral responses. In the current study, we investigated the therapeutic effect of natural chIFN-α administered via oral and intramuscular (i.m.) routes against ND in broiler chickens. Our results showed that the level of protection against ND in response to chIFN-α therapy was dependent on the route and dose of IFN administration. A better therapeutic effect was observed in chickens treated with chIFN-α via the oral route than in those treated via the i.m. route. Regardless of the administration route, double-dose chIFN-α (2,000-U) treatments provided better protection than single-dose (1,000-U) treatments. However, complete protection against ND was achieved in birds treated with repeated doses of chIFN-α via the oral route. Histopathology of trachea, proventriculus, spleen, and liver showed a significant improvement in ND-induced degenerative changes in double-dose IFN-treatment groups compared to single-dose groups. Results of the hemagglutination test demonstrated a decrease in ND virus (NDV) titer in IFN-treated groups. Also, double doses of chIFN-α via oral route resulted in early recovery in weight gain. We propose that chIFN-α therapy via oral route could be an important therapeutic tool to control NDV infection in chicken.

IMPORTANCE Newcastle disease (ND) is an economically important contagious disease of wild and domestic birds worldwide. The disease causes severe economic losses in terms of production due to high mortality and morbidity in nonvaccinated chickens. Despite extensive vaccination approaches, Newcastle disease (ND) remains a permanent threat to the poultry industry worldwide. In the current study, we used natural chicken IFN-α as an innate immune modulator to counteract ND in chickens. We report that chIFN-α is effective in protecting the chickens against ND and also prevents shedding of the virus, which can then prevent further spread of the disease. We propose that in addition to vaccination, chIFN-α therapy could be an effective option for controlling ND in areas of endemicity.

Anti-chicken type I IFN countermeasures by major avian RNA viruses

Chicken type I interferons (type I IFNs) are key antiviral players of the chicken innate immune system and are considered potent antiviral agents against avian viral pathogens. Chicken type I IFNs are divided into three subtypes namely, chIFN-α, chIFN-β, and chIFN-κ. Viral pathogen-associated molecular patterns (PAMPs) recognized by their corresponding specific PRRs (pattern recognition receptors) induce the expression of chicken type I IFNs. Interaction of chicken type I IFNs with their subsequent IFN receptors results in the activation of the JAK-STAT pathway, which in turn activates hundreds of chicken interferon-stimulated genes (chISGs). These chISGs establish an antiviral state in neighboring cells and prevent the replication and dissemination of viruses within chicken cells. Chicken type I IFNs activate different pathways that constitute major antiviral innate defense mechanisms in chickens. However, evolutionary mechanisms in viruses have made them resistant to these antiviral players by manipulating host innate immune pathways. This review focuses on the underlying molecular mechanisms employed by avian RNA viruses to counteract chicken type I IFNs and chISGs through different viral proteins. This may help to understand host-pathogen interactions and the development of novel therapeutic strategies to control viral infections in poultry.