Kaya, HacerKamiloğlu, Aybike2026-09-012026-09-0120261304-7582https://doi.org/10.24323/akademik-gida.1970697https://hdl.handle.net/20.500.12403/8358This study investigated the influence of the consumption of hawthorn (Crataegus tanacetifolia) fruit vinegar (HFV), a fermented product, on meat quality and gut microbiota in broiler chickens under cyclic heat stress (HS). A total of 300 one-day-old male Ross 308 chicks were divided into six groups with five replicates of ten birds, following a 2×3 factorial design with two temperatures (24 and 35°C) and three HFV supplementing levels (0, 2, and 4 mL/L) after one-week acclimation. Broilers in the thermoneutral groups were kept at 24°C, while HS groups experienced 35°C for 8 hours daily from day 21. Feed and water were provided ad libitum under a 24-hour lighting program. HS increased breast pH, reduced b* color value, raised ?SFA and ?MUFA levels, and lowered ?UFA and ?PUFA ratios. Supplementing 4 mL/L HFV increased breast L* color value and ?SFA level while reducing ?UFA ratio. The 2 mL/L HFV dose decreased ?MUFA and increased ?PUFA levels. Overall, HFV supplementation improved meat quality and beneficially altered fatty acid composition in heat-stressed broiler breasts. These results suggest that HFV supplementation may be a practical natural additive for broilers under cyclic heat stress and provide new evidence regarding its combined effects on meat quality and intestinal microbiota. Content of this journal is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.eninfo:eu-repo/semantics/openAccessAlıç Meyve SirkesiBağırsak MikroflorasıBroiler ChickensEt KalitesiEtlik PiliçHawthorn Fruit VinegarHeat StressIntestinal MicrofloraIsı StresiMeat QualityArticle24192110.24323/akademik-gida.19706972-s2.0-105045227636Q4