{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T03:30:50Z","timestamp":1788406250698,"version":"build-2803163510"},"reference-count":88,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,2,7]],"date-time":"2021-02-07T00:00:00Z","timestamp":1612656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000199","name":"USDA","doi-asserted-by":"publisher","award":["1712001657"],"award-info":[{"award-number":["1712001657"]}],"id":[{"id":"10.13039\/100000199","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The aim of this study was to evaluate the effect of a synbiotic containing a probiotic (Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis, and Lactobacillus reuteri) and a prebiotic (fructooligosaccharides) on fear response, memory assessment, and selected stress indicators in broilers subjected to heat stress. A total of 360 1-day-old Ross 708 chicks were evenly divided among three treatments: a basal diet mixed with a synbiotic at 0 (G-C), 0.5 (G-0.5X), and 1.0 (G-1.0X) g\/kg. After 15 d, the broilers were exposed to 32 \u00b0C for 9 h daily until 42 d. The object memory test was conducted at 15 day; touch, novel object, and isolation tests were conducted at 35 day; tonic immobility (TI) took place at 41 day. At 42 day, plasma corticosterone and tryptophan concentrations and heterophile\/lymphocyte (H\/L) ratios were measured. Compared to controls, synbiotic-fed broilers, regardless of concentration, had a shorter latency to make the first vocalization, with higher vocalization rates during the isolation test (p = 0.001). the G-1.0 group had the lowest H\/L ratio (p = 0.001), but higher plasma tryptophan concentrations and a greater number of birds could reach the observer during the touch test (p = 0.001 and 0.043, respectively). The current results indicate that the synbiotic can be used as a growth promoter to reduce the fear response and stress state of heat-stressed broilers.<\/jats:p>","DOI":"10.3390\/ani11020427","type":"journal-article","created":{"date-parts":[[2021,2,8]],"date-time":"2021-02-08T20:51:51Z","timestamp":1612817511000},"page":"427","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Effect of a Synbiotic Supplement on Fear Response and Memory Assessment of Broiler Chickens Subjected to Heat Stress"],"prefix":"10.3390","volume":"11","author":[{"given":"Ahmed","family":"Mohammed","sequence":"first","affiliation":[{"name":"Department of Animal Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA"},{"name":"Department of Animal and Poultry Behavior and Management, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7441-006X","authenticated-orcid":false,"given":"Manal","family":"Mahmoud","sequence":"additional","affiliation":[{"name":"Department of Animal Hygiene, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1285-2126","authenticated-orcid":false,"given":"Raj","family":"Murugesan","sequence":"additional","affiliation":[{"name":"BIOMIN America Inc., Overland Park, KS 66210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heng-wei","family":"Cheng","sequence":"additional","affiliation":[{"name":"USDA Agricultural Research Service, 125 South Russell Street, West Lafayette, IN 47907, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7477","DOI":"10.1038\/s41598-017-07536-7","article-title":"Humid heat waves at different warming levels","volume":"7","author":"Russo","year":"2017","journal-title":"Sci. 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