title: Effects of long-term heat stress in an experimental model of avian necrotic enteritis.
abstract: Stressful conditions are predisposing factors for disease development. Heat stress is one of the most important stressors in poultry production. The reemergence of some previously controlled diseases [e.g., avian necrotic enteritis (NE)] has been extensively reported. The combination of bacterial infection and certain environmental factors have been reported to trigger the disease. The aim of this study was to analyze the effects of long-term heat stress (35 ± 1°C) on the development of NE in broiler chickens. For this purpose, 60 male broiler chickens were divided into the following 6 groups: control group (C), heat stressed control group (C/HS35), thioglycolate group (T), thioglycolate heat-stressed group (T/HS35), infected group (I), and infected heat-stressed group (I/HS35). The poultry of groups I and I/HS35 were experimentally infected with Clostridium perfringens via their feed from 15 to 21 d of life. Heat stress (35 ± 1°C) was constantly applied to the birds of the stressed groups from 14 to 21 d of life. The infected and heat-stressed broiler chickens presented a trend toward a decrease in gross lesion scores and significantly lower microscopic scores of necrosis in the duodenum and jejunum (P < 0.05), lower fusion of villi in the duodenum (P < 0.05), and lower congestion scores in the jejunum and ileum (P < 0.05) in relation to infected and non-heat-stressed chickens. Broilers of I/HS35 group also exhibited small number of heterophils in the duodenum and jejunum compared with those of the I group (P < 0.05). Furthermore, the duodenum and jejunum of infected and heat-stressed broilers showed lower number of clostridia on the intestinal mucosa (P < 0.05). Data were discussed in light of a heat stress induced reduction on intestinal inflammation via a decrease in heterophil migration to the intestinal mucosa, which in turn might have reduced tissue damage during inflammation, hence preventing the development of a more severe form of NE.
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900.
authors.forename: Atilio Sersun
authors.initials: AS
authors.lastname: Calefi
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900.
authors.forename: Bruno Takashi Bueno
authors.initials: BT
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 05508-900.
authors.forename: Carolina
authors.initials: C
authors.lastname: Costola-de-Souza
authors.affiliation: Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900.
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 05508-900.
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 05508-900.
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 05508-900.
authors.forename: Juliana Garcia da Silva
authors.initials: JG
authors.lastname: Fonseca
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900.
authors.forename: Thiago Pinheiro Arrais
authors.initials: TP
authors.lastname: Aloia
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900.
authors.forename: Antonio José
authors.initials: AJ
authors.lastname: Piantino-Ferreira
authors.affiliation: Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil 05508-900 jpalermo@usp.br.
authors.forename: João
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000818:Animals; D002645:Chickens; D003015:Clostridium Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D003016:Clostridium perfringens / Q000502:physiology*; D004751:Enteritis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D018882:Heat Stress Disorders / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D007410:Intestinal Diseases / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D007421:Intestine, Small / Q000187:drug effects / Q000382:microbiology* / Q000473:pathology; D008297:Male; D009336:Necrosis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000382:microbiology* / Q000473:pathology; D011897:Random Allocation; D013864:Thioglycolates / Q000008:administration & dosage
chemical_list: D013864:Thioglycolates
keywords: Clostridium perfringens; avian necrotic enteritis; heat stress