Nasal delivery of chitosan-coated poly(lactide-co-glycolide)-encapsulated honeybee (Apis mellifera) venom promotes Th 1-specific systemic and local intestinal immune responses in weaned pigs

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

The intense nature of pig production has increased the animals’ exposure to stressful conditions, which may be detrimental to their welfare and productivity. Some of the most common sources of stress in pigs are extreme thermal conditions (thermal stress), density and mixing during housing (social stress), or exposure to pathogens and other microorganisms that may challenge their immune system (immune-related stress). The stress response can be monitored based on the animals’ coping mechanisms, as a result of specific environmental, social, and health conditions. These animal-based indicators may support decision making to maintain animal welfare and productivity. The present study aimed to systematically review animal-based indicators of social, thermal, and immune-related stresses in farmed pigs, and the methods used to monitor them. Peer-reviewed scientific literature related to pig production was collected using three online search engines: ScienceDirect, Scopus, and PubMed. The manuscripts selected were grouped based on the indicators measured during the study. According to our results, body temperature measured with a rectal thermometer was the most commonly utilized method for the evaluation of thermal stress in pigs (87.62%), as described in 144 studies. Of the 197 studies that evaluated social stress, aggressive behavior was the most frequently-used indicator (81.81%). Of the 535 publications examined regarding immune-related stress, cytokine concentration in blood samples was the most widely used indicator (80.1%). Information about the methods used to measure animal-based indicators is discussed in terms of validity, reliability, and feasibility. Additionally, the introduction and wide spreading of alternative, less invasive methods with which to measure animal-based indicators, such as cortisol in saliva, skin temperature and respiratory rate via infrared thermography, and various animal welfare threats via vocalization analysis are highlighted. The information reviewed was used to discuss the feasible and most reliable methods with which to monitor the impact of relevant stressors commonly presented by intense production systems on the welfare of farmed pigs.

Nasal delivery of chitosan/alginate nanoparticle encapsulated bee (Apis mellifera) venom promotes antibody production and viral clearance during porcine reproductive and respiratory syndrome virus infection by modulating T cell related responses

In this study, we administered specially developed chitosan/alginate nanoparticle encapsulated BV (CH/AL-BV) which has slow-releasing properties and mucosal adhesiveness to pig via nasal route and evaluate whether it can facilitate systemic immune response and improve clearance of porcine reproductive and respiratory syndrome virus (PRRSV). The CH/AL-BV-administered group with PRRSV vaccination showed significantly enhanced Th1-related responses including a high population of CD4⁺ T lymphocyte and cytokine mRNA levels including interferon-gamma (IFN-γ) and interleukin (IL)-12 and increased PRRSV-specific IgG levels. In the PRRSV challenge experiment, the CH/AL-BV group showed a significant decrease of viral burden in the sera and tissues (lung and bronchial lymph node) and mild interstitial pneumonia signs on both lung gross examination and microscopic evaluation with high levels of PRRSV-specific IgG and viral neutralizing antibody. CH/AL-BV also effectively induced not only Th1-related immune responses including increase in portion of CD4⁺ T lymphocyte, cytokines (IFN-γ and IL-12), and transcriptional factors (STAT4 and T-bet), but also stimulated IFN-γ-secreting cell families such as CD4⁺ T lymphocytes and Th/memory cells. Interestingly, the CH/AL-BV group showed decrease in PRRSV-specific immune-suppressive actions, including the T regulatory cell population and its related cytokines (IL-10 and TGF-β) and transcriptional factors (STAT5 and Foxp3). Therefore, nasal-delivered CH/AL-BV may effectively induce non-specific immune stimulating actions, particularly those related to Th1 responses and viral clearance activities against PRRSV infection. Based on these results, CH/AL-BV could be a promising strategy for overcoming the disadvantages of classical PRRSV vaccination and can be applied as a preventive agent against PRRSV and other viral diseases, particularly those with immune-suppressive characteristics.

Nasal drug delivery: Design of a novel mucoadhesive and in situ gelling polymer

The aim of the present study was to establish a novel polymeric excipient for liquid nasal dosage forms exhibiting viscosity increasing properties, improved mucoadhesion and stability towards oxidation in solution. In order to achieve this goal, 2-mercaptonicotinic acid was first coupled to l-cysteine by disulfide exchange reaction and after purification directly attached to the polymeric backbone of xanthan gum by carbodiimide mediated amide bond formation. The resulting conjugate was characterized with respect to the amount of coupled ligand, the in situ gelling behavior, mucoadhesive properties and stability towards oxidation. Furthermore, the influence of preactivated polymers on ciliary beat frequency (CBF) of porcine nasal epithelial cells was investigated. Results showed, that 252.52±20.54μmol of the ligand was attached per gram polymer. No free thiol groups could be detected on the polymeric backbone indicating entire preactivation. Rheological investigations of polymer mucus mixtures revealed a 1.7-fold and 2.5-fold enhanced mucoadhesion of entirely preactivated xanthan (Xan-Cys-MNA) compared to thiolated xanthan (Xan-Cys) and unmodified xanthan (Xan). Tensile force evaluation reported a 2.87 and 5.11-fold higher total work of adhesion (TWA) as well as a 1.63 and 2.41-fold higher maximum detachement force of Xan-Cys-MNA compared to Xan-Cys and Xan. In the presence of H₂O₂ as an oxidizing agent Xan-Cys-MNA showed unlike Xan-Cys no increase in viscosity, indicating high stability towards oxidation. Addition of CaCl₂ to Xan-Cys-MNA solutions caused a decrease in viscosity at nevertheless higher total viscosity. Results from CBF studies proved nasal safety for the novel conjugate. According to these results, entirely preactivated thiolated xanthan gum seems to be a promising excipient for nasal dosage forms in order to improve drug bioavailability.