Journal articles

Bivalent oral vaccine using attenuated salmonella gallinarum delivering HA and NA-M2E confers dual protection against H9N2 avian influenza and fowl typhoid in chickens

Fri, 25 Jul 2025 00:00:00 GMT

Bivalent oral vaccine using attenuated salmonella gallinarum delivering HA and NA-M2E confers dual protection against H9N2 avian influenza and fowl typhoid in chickens Bakhsh, Muhammad; Senevirathne, Amal; Riaz, Jamal; Kwon, Jun; Aganja, Ram Prasad; Cabarles, Jaime C.; Oh, Sang-Ik; Lee, John Hwa Background: Fowl typhoid (FT), a septicemic infection caused by Salmonella Gallinarum (SG), and H9N2 avian influenza are two economically important diseases that significantly affect the global poultry industry. Methods: We exploited the live attenuated Salmonella Gallinarum (SG) mutant JOL3062 (SG: ∆lon ∆pagL ∆asd) as a delivery system for H9N2 antigens to induce an immunoprotective response against both H9N2 and FT. To enhance immune protection against H9N2, a prokaryotic and eukaryotic dual expression plasmid, pJHL270, was employed. The hemagglutinin (HA) consensus sequence from South Korean avian influenza A virus (AIV) was cloned under the Ptrc promoter for prokaryotic expression, and the B cell epitope of neuraminidase (NA) linked with matrix protein 2 (M2e) was placed for eukaryotic expression. In vitro and in vivo expressions of the H9N2 antigens were validated by qRT-PCR and Western blot, respectively. Results: Oral immunization with JOL3121 induced a significant increase in SG and H9N2-specific serum IgY and cloacal swab IgA antibodies, confirming humoral and mucosal immune responses. Furthermore, FACS analysis showed increased CD4+ and CD8+ T cell populations. On day 28 post-immunization, there was a substantial rise in the hemagglutination inhibition titer in the immunized birds, demonstrating neutralization capabilities of immunization. Both IFN-γ and IL-4 demonstrated a significant increase, indicating a balance of Th1 and Th2 responses. Intranasal challenge with the H9N2 Y280 strain resulted in minimal to no clinical signs with significantly lower lung viral titer in the JOL3121 group. Upon SG wildtype challenge, the immunized birds in the JOL3121 group yielded 20% mortality, while 80% mortality was recorded in the PBS control group. Additionally, bacterial load in the spleen and liver was significantly lower in the immunized birds. Conclusions: The current vaccine model, designed with a host-specific pathogen, SG, delivers a robust immune boost that could enhance dual protection against FT and H9N2 infection, both being significant diseases in poultry, as well as ensure public health. Journal article DOI: https://doi.org/10.3390/vaccines13080790

A comparative study of hematological profiles and Mycoplasma gallisepticum prevalence in Philippine native chickens raised using CPU technology and backyard free-range methods

Wed, 01 Jan 2025 00:00:00 GMT

A comparative study of hematological profiles and Mycoplasma gallisepticum prevalence in Philippine native chickens raised using CPU technology and backyard free-range methods Depasupil, Allyssa M.; Cabarles, Jaime Jr. Philippine Native chickens are typically raised using a free-range system in backyards. The management style is characterized by its low-input, low-output nature. To address the growing demand for native chicken, production is intensified through the strategic use of available feed resources, occasionally supplemented with commercial feed additives. Native chickens exhibit notable disease resistance and adaptability to local climatic conditions, making them more favored by local communities. However, these free-ranging habits expose them to diseases and nutritional deficiencies. In response to the identified challenges, Central Philippine University developed a technology package for raising native chickens. This innovative approach features confined housing and employs antibiotic-free feeding management and phytomedicines. This technology was evaluated, focusing on the hematological profiles and the prevalence of Mycoplasma gallisepticum in native chickens. The findings revealed that 73% of the sample population of backyard chickens tested positive for M. gallisepticum infection, whereas chickens raised under CPU technology exhibited only a 6% positive rate. Hematological and antibody test results corroborated these findings, allowing for practical disease evaluation. Notably, the free-range chickens displayed elevated mean corpuscular volume (MCV) values compared to standard reference ranges. Hence, this technological application significantly reduced the incidence of M. gallisepticum in native chickens, addressing a respiratory disease that leads to an alteration in erythrocyte size. Journal article

Sensitivity, specificity, and accuracy evaluation of a colorimetric detection kit for Mycoplasma gallisepticum in chickens using green-synthesized gold nanoparticles and IgY conjugates

Wed, 01 Oct 2025 00:00:00 GMT

Sensitivity, specificity, and accuracy evaluation of a colorimetric detection kit for Mycoplasma gallisepticum in chickens using green-synthesized gold nanoparticles and IgY conjugates Depasupil, Allyssa M.; Vicentino, Neil Francis; Dobleo, Lhyssa Marie; Fernandez, Karen Jee; Cabarles, Jaime Jr. Mycoplasma gallisepticum is a significant pathogen affecting poultry production, causing chronic respiratory disease and substantial economic losses. This study evaluated a colorimetric detection kit for M. gallisepticum using green-synthesized gold nanoparticles (AuNPs) from cashew leaves conjugated with immunoglobulin Y (IgY) antibodies. The kit was field-tested on 20 chickens and compared with microbial culture results. The detection kit demonstrated 100% specificity and positive predictive value, indicating its ability to accurately identify true positive cases. However, it showed limited sensitivity (52.38%) and accuracy (54.55%), with a low negative predictive value (9.09%). The kit provided rapid results within 30 minutes compared to 24 hours for microbial testing and was cost-effective at 15.00 PHP per test. While the kit successfully detected subclinical infections, its performance could be improved through further optimization of antibody-antigen binding and larger-scale field testing. Integrating the rapid colorimetric test with confirmatory microbial testing is recommended for enhanced reliability in field settings. Future research should focus on adapting this technology for other poultry pathogens and assessing its economic impact on poultry farming operations. Journal article

Environmental effects on the resistance of rice seedlings to complete submergence

Wed, 01 Mar 1972 00:00:00 GMT

Environmental effects on the resistance of rice seedlings to complete submergence Palada, Manuel C.; Vergara, Benito S. The survival of rice seedlings (Oryza sativa L.) after complete Submergence in water decreased with increased duration of submergence; with increased depth, temperature, and turbidity of water; and with increased rates of N fertilization. Survival increased with high light intensity and plant carbohydrate content. Factors that influence the survival of submerged plants also determine the amounts of N and carbohydrate in the plant. Journal article