Investigation of Fas (APO-1)-Related Apoptosis in Piglets Intradermally or Intramuscularly Vaccinated with a Commercial PRRSV MLV

The role of visfatin in peripheral immune organs and intestines of weaned piglets under lipopolysaccharide induced immune stress

To investigate the regulatory mechanisms and pathways of visfatin under immune stress injury in weaned piglets, we established a lipopolysaccharide-induced immune stress model in weaned piglets to study how visfatin affects peripheral immune organs and intestinal function. The results revealed that visfatin improved the inflammatory response in immune-stressed weaned piglets by reducing the levels of pro-inflammatory cytokines interleukin-1β, interleukin-6 and monocyte chemoattractant protein-1, as well as decreasing the neutrophil/lymphocyte ratio. Visfatin ameliorated oxidative stress in piglets by promoting the expression of superoxide dismutase and glutathione peroxidase. It also enhanced cell proliferation in peripheral immune organs (spleen and mesenteric lymph nodes) and suppressed cell apoptosis in these organs through the death receptor apoptosis pathway, thereby improving the immune function of weaned piglets under immune stress. Moreover, it alleviated intestinal villi damage, increased the abundance of beneficial bacteria, and elevated the levels of short-chain fatty acids, thus preserving the intestinal barrier's integrity and the balance of intestinal microbiota. Hence, these data indicate that visfatin can ameliorate immune stress injury in weaned piglets by exerting anti-inflammatory and antioxidant effects, enhancing immune organ and intestinal function.

Research Progress on the Development of Porcine Reproductive and Respiratory Syndrome Vaccines

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious disease in the pig industry, but its pathogenesis is not yet fully understood. The disease is caused by the PRRS virus (PRRSV), which primarily infects porcine alveolar macrophages and disrupts the immune system. Unfortunately, there is no specific drug to cure PRRS, so vaccination is crucial for controlling the disease. There are various types of single and combined vaccines available, including live, inactivated, subunit, DNA, and vector vaccines. Among them, live vaccines provide better protection, but cross-protection is weak. Inactivated vaccines are safe but have poor immune efficacy. Subunit vaccines can be used in the third trimester of pregnancy, and DNA vaccines can enhance the protective effect of live vaccines. However, vector vaccines only confer partial protection and have not been widely used in practice. A PRRS vaccine that meets new-generation international standards is still needed. This manuscript provides a comprehensive review of the advantages, disadvantages, and applicability of live-attenuated, inactivated, subunit, live vector, DNA, gene-deletion, synthetic peptide, virus-like particle, and other types of vaccines for the prevention and control of PRRS. The aim is to provide a theoretical basis for vaccine research and development.

Skin-Based Vaccination: A Systematic Mapping Review of the Types of Vaccines and Methods Used and Immunity and Protection Elicited in Pigs

The advantages of skin-based vaccination include induction of strong immunity, dose-sparing, and ease of administration. Several technologies for skin-based immunisation in humans are being developed to maximise these key advantages. This route is more conventionally used in veterinary medicine. Skin-based vaccination of pigs is of high relevance due to their anatomical, physiological, and immunological similarities to humans, as well as being a source of zoonotic diseases and their livestock value. We conducted a systematic mapping review, focusing on vaccine-induced immunity and safety after the skin immunisation of pigs. Veterinary vaccines, specifically anti-viral vaccines, predominated in the literature. The safe and potent skin administration to pigs of adjuvanted vaccines, particularly emulsions, are frequently documented. Multiple methods of skin immunisation exist; however, there is a lack of consistent terminology and accurate descriptions of the route and device. Antibody responses, compared to other immune correlates, are most frequently reported. There is a lack of research on the underlying mechanisms of action and breadth of responses. Nevertheless, encouraging results, both in safety and immunogenicity, were observed after skin vaccination that were often comparable to or superior the intramuscular route. Further research in this area will underlie the development of enhanced skin vaccine strategies for pigs, other animals and humans.

Evaluation of Intradermal PRRSV MLV Vaccination of Suckling Piglets on Health and Performance Parameters under Field Conditions

Porcine reproductive and respiratory syndrome virus (PRRSV) causes respiratory disease in weaning and growing pigs. A vaccination against PRRSV is one of the most important control measures. This trial aimed to evaluate the effect of the intradermal (ID) administration of a PRRSV-1 modified live virus (MLV) vaccine in comparison to the intramuscular (IM) administration on the piglets’ health and performance. A total of 187 suckling piglets of a PRRSV-positive commercial farrow-to-finish farm were assigned to four groups: group A—PRRSV ID, group B—PRRSV IM, group C—control ID, and group D—control IM. At 2 weeks of age, all the study piglets were either vaccinated with a PRRSV-1 MLV vaccine or injected with the vaccine adjuvant (controls). The collected blood serum samples were tested by ELISA and qRT-PCR. The side effects, body weight (BW), average daily gain (ADG), mortality rate, and lung and pleurisy lesions scores (LLS, PLS) were also recorded. The ELISA results indicated that the vaccination induced an important seroconversion at 4 and 7 weeks. Significant differences in the qRT-PCR results were noticed only at 10 weeks in group A vs. group C (p < 0.01) and group B vs. group C (p < 0.05). High viral loads, as evidenced by the qRT-PCR Ct values, were noticed in animals of both non-vaccinated groups at 7, 10, and 13 weeks. An ID vaccination has a positive impact on the BW at the piglets’ slaughter, while both an ID and IM vaccination had a positive impact on the ADG. The mortality rate was lower in vaccinated groups at the finishing stage. The LLS and PLS were significantly lower in the vaccinated groups. In conclusion, our study demonstrated that the ID vaccination of suckling piglets with a PRRSV-1 MLV vaccine has a positive effect on the piglets’ health and performance, including an improved BW and a lower LLS and PLS index at their slaughter, as well as a decreased mortality rate at the growing/finishing stage.

Angiotensin II Blood Serum Levels in Piglets, after Intra-Dermal or Intra-Muscular Vaccination against PRRSV

Simple Summary

Porcine reproductive and respiratory syndrome virus (PRRSV) infection causes massive financial losses in pig production worldwide. Vaccination is still the most cost-effective tool to handle PRRSV infection. PRRSV induces apoptosis in different organs. Angiotensin II (Ang II) participates in the inflammatory response, cell proliferation, migration, and apoptosis. The objective of the current study was to assess the concentration of Ang II in the serum of piglets following immunization against PRRSV through intradermal (ID) or intramuscular (IM) vaccination with a commercial PRRS modified live virus (MLV) vaccine. The results indicated differences in viremia of tested piglets at 7 weeks of age, while piglets at 10 weeks of age were all found qRT-PCR positive for PRRSV. Moreover, significant differences were noticed in Ang II in 7-week-old piglets. In conclusion, our study provides evidence that ID vaccination induces less tissue damage, based on the lower measurements of Ang II in the serum of ID vaccinated piglets.

Abstract

The Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) induces apoptosis in different organs. Angiotensin II (Ang II) is the main effector of the renin-angiotensin system and participates in apoptosis. Thus, this study aimed to investigate changes in piglet serum Ang II levels following intradermal (ID) and intramuscular (IM) vaccination with a commercial PRRS modified live virus (MLV) vaccine. The trial was conducted in a commercial pig farm, including 104 piglets which were randomly allocated to four groups: Group A—Porcilis PRRS ID, Group B—Porcilis PRRS IM, Group C—Diluvac ID and Group D—Diluvac IM. The study piglets were either vaccinated or injected at 2 weeks of age and they were tested by qRT-PCR for PRRSV and by ELISA for Ang II. The results indicated differences in viremia of tested piglets at 7 weeks of age, while piglets at 10 weeks of age were all found qRT-PCR positive for PRRSV. In addition, significant differences were noticed in Ang II in 7-week-old piglets. In conclusion, the present study provides evidence that ID vaccination induces less tissue damage, based on the lower measurements of Ang II in the serum of ID vaccinated piglets.