title: Effects of heat stress on the formation of splenic germinal centres and immunoglobulins in broilers infected by Clostridium perfringens type A.
abstract: Avian necrotic enteritis (NE) induced by Clostridium perfringens is a disease that affects mainly the first weeks of poultry's life. The pathogenesis of NE is complex and involves the combination of several factors, such as co-infection with different species of coccidia, immunosuppression and stress. Stress is one of the main limiting factors in poultry production. Although several studies emphasized the effects of stress on immunity, few works analyzed these effects on immunoglobulins and on germinal centres (GCs), which are specialized microenvironments, responsible for generating immune cells with high affinity antibodies and memory B-lymphocytes. Thus, the effects of heat stress associated or not with thioglycolate broth culture medium intake and/or C. perfringens infection on corticosterone serum levels, spleen GCs development and immunoglobulin production in broilers were evaluated. Results showed that heat stress, thioglycolate and C. perfringens per se increased corticosterone serum levels, although this was not observed in heat stressed and thioglycolate and C. perfringens-treated chickens. The serum levels of IgA, IgM and IgY were differently affected by heat stress and/or infection/thioglycolate. Heat stress decreased the duodenal concentrations of sIgA, which was accompanied by a reduction in GCs number in the duodenal lamina propria; a trend to similar findings of sIgA concentrations was observed in the chickens' jejunum. Changes in spleen and Bursa of Fabricius relative weights as well as in spleen morphometry were also noted in heat stressed animals, infected or not. Together, these data suggest that heat stress change GCs formation in chickens infected or not, which that may lead to failures in vaccination protocols as well as in the poultries' host resistance to infectious diseases during periods of exposure to heat stress.
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: ascalefi@gmail.com.
authors.forename: Atílio Sersun
authors.initials: AS
authors.lastname: Calefi
authors.affiliation: Department of Pathology, School of Veterinary Medicine and Animal Science University of São Paulo, São Paulo, Brazil. Electronic address: siqueira.adriana.vp@gmail.com.
authors.forename: Adriana
authors.initials: A
authors.lastname: de Siqueira
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: lilicanamazu@usp.br.
authors.forename: Lilian Bernadete
authors.initials: LB
authors.lastname: Namazu
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: ccostola@gmail.com.
authors.forename: Carolina
authors.initials: C
authors.lastname: Costola-de-Souza
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: brunothonda@gmail.com.
authors.forename: Bruno Bueno Takashi
authors.initials: BB
authors.lastname: Honda
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: ajpferr@usp.br.
authors.forename: Antonio José Piantino
authors.initials: AJ
authors.lastname: Ferreira
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: quinteirofilho@gmail.com.
authors.forename: Wanderley Moreno
authors.initials: WM
authors.lastname: Quinteiro-Filho
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: julianagdsf@gmail.com.
authors.forename: Juliana Garcia
authors.initials: JG
authors.lastname: da Silva Fonseca
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. Electronic address: jpalermo@usp.br.
authors.forename: João
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000276:immunology*; D003015:Clostridium Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D003016:Clostridium perfringens; D003345:Corticosterone / Q000097:blood; D004386:Duodenum / Q000276:immunology; D004751:Enteritis / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D018858:Germinal Center / Q000276:immunology / Q000473:pathology; D018869:Heat-Shock Response; D006358:Hot Temperature; D007136:Immunoglobulins / Q000276:immunology; D008297:Male; D009929:Organ Size; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D013154:Spleen / Q000473:pathology*
chemical_list: D007136:Immunoglobulins; D003345:Corticosterone
keywords: Avian necrotic enteritis; Histomorphometry; Neuroimmunomodulation; Stereology