title: Differences in Susceptibility to Heat Stress along the Chicken Intestine and the Protective Effects of Galacto-Oligosaccharides.
abstract: High ambient temperatures negatively affect the human well-being as well as animal welfare and production. The gastrointestinal tract is predominantly responsive to heat stress. The currently available information about the multifaceted response to heat stress within different parts of the intestine is limited, especially in avian species. Hence, this study aims to evaluate the heat stress-induced sequence of events in the intestines of chickens. Furthermore, the gut health-promoting effect of dietary galacto-oligosaccharides (GOS) was investigated in these heat stress-exposed chickens. Chickens were fed a control diet or diet supplemented with 1% or 2.5% GOS (6 days) prior to and during a temperature challenge for 5 days (38-39°C, 8h per day). The parameters measured in different parts of the intestines included the genes (qPCR) HSF1, HSF3, HSP70, HSP90, E-cadherin, claudin-1, claudin-5, ZO-1, occludin, TLR-2, TLR-4, IL-6, IL-8, HO-1, HIF-1α) and their associated proteins HSP70, HSP90 and pan-cadherin (western blots). In addition, IL-6 and IL-8 plasma concentrations were measured by ELISA. In the jejunum, HSF3, HSP70, HSP90, E-cadherin, claudin-5, ZO-1, TLR-4, IL-6 and IL-8 mRNA expression and HSP70 protein expression were increased after heat stress exposure and a more pronounced increase in gene expression was observed in ileum after heat stress exposure, and in addition HSF1, claudin-1 and HIF-1α mRNA levels were upregulated. Furthermore, the IL-8 plasma levels were decreased in chickens exposed to heat stress. Interestingly, the heat stress-related effects in the jejunum were prevented in chickens fed a GOS diet, while dietary GOS did not alter these effects in ileum. In conclusion, our results demonstrate the differences in susceptibility to heat stress along the intestine, where the most obvious modification in gene expression is observed in ileum, while dietary GOS only prevent the heat stress-related changes in jejunum.
authors.affiliation: Division of Veterinary Pharmacy, Pharmacology and Toxicology, Utrecht University, Utrecht, The Netherlands; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: Soheil
authors.initials: S
authors.lastname: Varasteh
authors.affiliation: Division of Veterinary Pharmacy, Pharmacology and Toxicology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Saskia
authors.initials: S
authors.lastname: Braber
authors.affiliation: Division of Veterinary Pharmacy, Pharmacology and Toxicology, Utrecht University, Utrecht, The Netherlands; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: Peyman
authors.initials: P
authors.lastname: Akbari
authors.affiliation: Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands; Nutricia Research, Utrecht, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Garssen
authors.affiliation: Division of Veterinary Pharmacy, Pharmacology and Toxicology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Johanna
authors.initials: J
authors.lastname: Fink-Gremmels
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002645:Chickens; D004032:Diet; D005690:Galactose / Q000494:pharmacology*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response / Q000187:drug effects; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D007082:Ileum / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015850:Interleukin-6 / Q000097:blood / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000097:blood / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects / Q000473:pathology; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009844:Oligosaccharides / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D015820:Cadherins; D006360:Heat-Shock Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015850:Interleukin-6; D016209:Interleukin-8; D009844:Oligosaccharides; D020011:Protective Agents; D012333:RNA, Messenger; D051197:Toll-Like Receptor 4; D005690:Galactose