@article{harding_boot_evans_shah_malheiros_anderson_2025, title={Determining how different ventilation shutdown plus methods change the electroencephalography, blood chemistry, corticosterone, and heat shock protein 70 of laying hens}, volume={16}, DOI={10.3389/fphys.2025.1534385}, abstractNote={The poultry industry faces a major impediment in dealing with highly pathogenic avian influenza (HPAI). Large outbreaks have resulted in depletion of available resources needed for desired depopulation methods, leading to the need for alternative methods. This study was conducted to explore alternative ventilation shutdown procedures and how they affect laying hens throughout the process. Three treatments evaluated were ventilation shutdown plus heat (VSDH), ventilation shutdown plus heat and relative humidity (VSDHRh), and ventilation shutdown plus carbon dioxide (VSDCO<sub>2</sub>). There were two phases used: one phase was used to study treatment effects on the hens' EEG responses from beginning to time of death and how laying hens behaved. Phase 2 examined how these treatments affected hen blood chemistry and HSP70 during the process. VSDCO<sub>2</sub> had a significantly quicker time of death (P = 0.0003), and VSDH and VSDHRh were not different. There were no differences in pre- or post-corticosterone levels in Phase 1; however, there was a trend (P = 0.07) toward significance in the post corticosterone levels. Heat shock protein 70 (HSP70) levels were higher (P = 0.0001) in the VSDCO<sub>2</sub> treatment, which could be due to the protein upregulation to prevent apoptosis. In Phase 2, VSDH corticosterone had a significantly greater treatment effect compared to VSDHRh and VSDCO<sub>2</sub>. corticosterone levels were significantly greater than those of VSDHRh. There were no significant treatment effects in Phase 2 for HSP70 expression; however, the sequence was significant, with the HSP70 being significantly greater at 75% to the average time of death than at 100% to the average time of death. Overall, VSDHRh could be a good alternative for the industry to use to rapidly depopulate laying hen facilities. However, more research on this treatment and more in-depth stress parameters measured needs to be conducted to fully determine how it affects laying hens.}, journal={Frontiers in Physiology}, author={Harding, Kari L. and Boot, Emmillie and Evans, Jackson O. and Shah, Sanjay B. and Malheiros, Ramon D. and Anderson, Kenneth E.}, year={2025}, month={Mar} }
 @article{harding_boot_evans_shah_malheiros_anderson_2025, title={The comparative effects of ventilation shutdown with heat (VSDH), relative humidity (VSDHRh), or CO2 (VSDCO2) on broiler electroencephalogram (EEG), blood chemistry and gene expression}, volume={34}, url={https://doi.org/10.1016/j.japr.2025.100541}, DOI={10.1016/j.japr.2025.100541}, abstractNote={Highly Pathogenic Avian Influenza (HPAI) outbreaks have highlighted major needs for multiple effective depopulation methods across all sectors and housing systems in the commercial poultry industry. Ventilation shutdown plus heat (VSDH), heat and relative humidity (VSDHRh), and carbon dioxide (VSDCO 2 ) were analyzed to understand how these methods affect broiler stress parameters and behavior. Two phases were used with both phases being conducted in sealable Plexiglass® chambers. Phase 1 (P1) analyzed electroencephalogram (EEG) of each broiler in each treatment along with blood chemistry, corticosterone, and heat shock protein 70 (HSP70) at time of death (TOD). Phase 2 (P2) looked at the progression of the stress parameters over time with specific physiological points when birds were removed from their respective chamber. There was a significant difference (P<0.0001) between time of death (TOD) with VSDCO 2 being significantly faster at 21.25 minutes compared to VSDH and VSDHRh at 63.75 and 58.25, respectively, in P1. However, there were no significant differences in the TOD between VSDH or VSDHRh. There was also a significant increase in chamber ending CO 2 , for VSDCO 2 compared to VSDH and VSDHRh. However, both VSDH and VSDHRh broilers had significantly greater (P<0.0001) post core body temperatures indicating hyperthermia being the mode of action rather than hypoxia which is the mode of action in VSDCO 2 . The HSP70 levels were significantly greater in VSDH at 1.23 CT -1 compared to both VSDHRh at 0.98 CT -1 and VSDCO 2 at 0.90 CT -1 , which were not significantly different from each other. Blood chemistry parameters that were significantly higher in VSDCO 2 treatment broilers when compared to VSDHRh were total CO 2 (TCO 2 ), partial pressure of CO 2 (pCO 2 ), partial pressure of oxygen (pO 2 ), Bicarbonate (HCO 3), and blood oxygen saturation (sO 2 ). When compared to VSDH, TCO 2 , pCO 2 , and sO 2 levels were significantly greater in broilers undergoing the VSDCO 2 treatment. There were also no significant differences in corticosterone between treatments in P1 with corticosterone levels for VSDH being 0.11 ng/mL, 0.10 ng/mL for VSDHRh, and 0.12 ng/mL for VSDCO 2 . When analyzing the effects of these treatments on broilers over time in P2, there were no significant differences in corticosterone, blood chemistry, or HSP70 when compared within their respective treatments. Based on this research, VSDHRh may be an effective and useful depopulation method that may be used in the event of an outbreak. This is due to the equivalency of TOD in comparison to VSDH, with potential reduction in HSP70 levels. More research should be conducted on the effects of VSDHRh, especially in a non-environmentally controlled setting.}, number={3}, journal={The Journal of Applied Poultry Research}, author={Harding, Kari L. and Boot, Emmillie and Evans, Jackson O. and Shah, Sanjay B. and Malheiros, Ramon D. and Anderson, Kenneth E.}, year={2025}, month={Apr} }