title: Effects of cold stress and Salmonella Heidelberg infection on bacterial load and immunity of chickens.
abstract: We analysed the effects of cold stress (19 ± 1°C, 6 h /day, from the first to the seventh day of life) applied to specific pathogen free (SPF) chickens. On experimental Day 1 (ED1), chicks were divided into four groups: C (not infected and kept under thermoneutral condition); CS (not infected and cold stressed); PC (Salmonella Heidelberg (SH) infected and kept under thermoneutral condition) and PCS (SH infected and cold stressed). High concentrations of corticosterone were found in the cold stressed birds on ED7 and ED21, with a greater increase in birds of the PCS group. Stress or non-stressed SH-infected birds had high levels of norepinephrine on ED21. On ED21, an increased percentage and number of SH were found in birds of the PCS group. On ED7, a decrease in macrophages presenting MHCII, CD8(+) and CD8(+) γδ cells was observed in the chickens of the CS group. Decrease was observed in CD3(+) cells in the birds of the PCS group and increase in macrophages presenting MHCII cells and of the CD4(+)/CD8(+) ratio in chickens of the CS group on ED21. There was a decrease in CD8(+) γδ cells in birds of the CS group on ED21 and in the CD3(+) and CD8(+)cell numbers in chickens of the PCS group on ED21. Our results suggest that cold stress applied to chickens in the first 7 days of life increases both the hypothalamus pituitary adrenal axis and the sympathetic nervous system activities, leading to long-term immune cell dysfunction, thus allowing increased SH invasion and persistence within the birds' body.
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Anderlise
authors.initials: A
authors.lastname: Borsoi
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Wanderley Moreno
authors.initials: WM
authors.lastname: Quinteiro-Filho
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Atilio Sersun
authors.initials: AS
authors.lastname: Calefi
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Antonio José Piantino
authors.initials: AJ
authors.lastname: Ferreira
authors.affiliation: b Laboratory of Ornithopathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Claudete Serrano
authors.initials: CS
authors.lastname: Astolfi-Ferreira
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: Jorge Camilo
authors.initials: JC
authors.lastname: Florio
authors.affiliation: a Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine , University of São Paulo , São Paulo 05508-270 , Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000818:Animals; D058491:Bacterial Load; D002395:Catecholamines / Q000097:blood; D002645:Chickens / Q000276:immunology* / Q000382:microbiology; D003080:Cold Temperature; D003345:Corticosterone / Q000097:blood; D007109:Immunity; D008264:Macrophages / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology; D012475:Salmonella / Q000276:immunology* / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000382:microbiology; D013047:Specific Pathogen-Free Organisms; D013312:Stress, Physiological
chemical_list: D002395:Catecholamines; D003345:Corticosterone