Protective Role of Probiotics Against Heat Stress in Japanese Quails: Insights from HSPs and MMP9 Expression Profiles

Heat stress is a major challenge in poultry production, disrupting cellular homeostasis and inducing oxidative and inflammatory responses. This study investigated the effects of chronic heat stress (30–34 °C) and supplementation with either a commercial or a laboratory-produced natural probiotic on the expression of heat shock proteins (HSP60, HSP70, HSP90) and matrix metalloproteinase 9 (MMP9) in Japanese quails (Coturnix japonica). Thirty-six healthy, 6-week-old quails were randomly allocated to six experimental groups maintained under thermoneutral or heat-stress conditions and supplemented with probiotics accordingly. Gene expression in cecal tissue was analyzed by real-time PCR, and protein concentrations in serum were measured by ELISA. Heat stress significantly increased the expression of HSP70 and HSP90, confirming their role as key molecular chaperones involved in the cellular stress response. Elevated HSP60 expression in heat-stressed control birds further suggested mitochondrial involvement under thermal challenge. In addition, MMP9 expression was significantly upregulated in heat-stressed groups, indicating activation of extracellular matrix remodelling and inflammatory pathways. Probiotic supplementation significantly modulated these molecular responses, with effects that depended on the probiotic formulation. The commercial probiotic markedly reduced HSP70, HSP90, and MMP9 levels under heat stress, suggesting attenuation of stress-related signalling. In contrast, the natural probiotic reduced HSP70 expression while maintaining higher HSP60 levels and inducing increased MMP9 expression, indicating a distinct regulatory pattern potentially associated with mitochondrial involvement and controlled tissue remodelling. In conclusion, chronic heat stress alters both intracellular chaperone systems and extracellular remodelling pathways in Japanese quails. Probiotic supplementation modulates these responses in a formulation-dependent manner. While the commercial probiotic primarily suppressed stress-associated markers, the natural probiotic promoted a more differentiated molecular response. These findings highlight the importance of probiotic selection when designing nutritional strategies to mitigate the adverse effects of heat stress in poultry. Supplementary Material File (figure_1.docx) - Download - 17.66 KB File (figure_2.docx) - Download - 17.36 KB File (figure_3.docx) - Download - 17.31 KB File (figure_4.docx) - Download - 19.33 KB File (figure_5.docx) - Download - 19.11 KB File (figure_6.docx) - Download - 19.20 KB File (main document.docx) - Download - 270.19 KB File (table_1.docx) - Download - 15.50 KB File (table_2.docx) - Download - 15.17 KB Information & Authors Information Version history Copyright This work is licensed under a Non Exclusive No Reuse License.

Authors Metrics & Citations Metrics Article Usage 121views 49downloads Citations Download citation Özlem Bedir, Deniz KORKMAZ, Akın YİĞİN, et al. Protective Role of Probiotics Against Heat Stress in Japanese Quails: Insights from HSPs and MMP9 Expression Profiles. Authorea. 31 December 2025. DOI: https://doi.org/10.22541/au.176715196.65514278/v1 DOI: https://doi.org/10.22541/au.176715196.65514278/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.