RESUMO
Genetic selection for fast growth can affect the ability of male turkeys to cope with stressors, resulting in decreased immunity to opportunistic bacterial infection. The purpose of the current study was to compare the effects of ascorbic acid (AA) on the stress response and resistance to Escherichia coli challenge of birds selected for increased 16-wk body weight (BW; F-line) with their random-bred parent line (RBC2). Male turkeys were raised in duplicate floor pens in a two line×two AA treatment×two stress challenge (SC) design. At 5 wk of age, AA (1200 ppm) was provided in drinking water for a 24-hr period, during which all birds were weighed. After AA treatment, the SC group was subjected to a transport stress protocol. Six hours after the start of transport, SC birds were also inoculated in the thoracic air sac with 1×10(4) colony-forming units of E. coli. The following morning four birds from each pen were bled, and all birds were weighed and necropsied 2 days later. BW and gain after SC were decreased in the F-line but not the RBC2 line, and there were no AA effects on BW. The weight of the bursa of Fabricius relative to BW was higher in the RBC2 line than in the F-line, was decreased by SC, and was not affected by AA. The heterophilâ¶lymphocyte ratio was higher in the SC F-line as compared to the SC RBC2 and was decreased by AA only in the SC F-line. Corticosterone (C) levels were increased by SC only in the F-line, and AA decreased C levels only in the RBC2 line. Airsacculitis scores were increased in the F-line SC birds. The challenge strain of E. coli was only detected in the air sac and liver of the AA-treated F-line SC birds and in the liver of the no-AA F-line birds. These results suggest that SC at 5 wk of age had a more deleterious effect on the fast-growing F-line than on its parent line and that AA may have increased susceptibility to colibacillosis in the SC F-line birds.
Assuntos
Ácido Ascórbico/farmacologia , Infecções por Escherichia coli/veterinária , Doenças das Aves Domésticas/microbiologia , Estresse Fisiológico/efeitos dos fármacos , Perus/crescimento & desenvolvimento , Perus/genética , Animais , Suplementos Nutricionais , Infecções por Escherichia coli/microbiologia , Masculino , Doenças das Aves Domésticas/tratamento farmacológico , Perus/fisiologiaRESUMO
Femoral head separation (FHS) is a degenerative skeletal problem in fast-growing poultry wherein the growth plate of the proximal femur separates from its articular cartilage. At its early phase, FHS may remain asymptomatic but lead to epiphyseal breakage, infection, and femoral head necrosis (FHN). Healthy femoral head is viewed as a positive trait for genetic selection. However, the etiology of FHS is poorly understood for use in noninvasive diagnosis and genetic selection. Focal cell death and atrophic changes are likely associated with separation of tissues and necrotic changes. Fibrotic thickening of the articular surface can also impair free movement of the proximal epiphysis in the acetabulum, leading to FHS, under strain. The major limitation to understanding the pathophysiology of FHN is the lack of suitable experimental models and biomarkers to diagnose the problem. In this review, we discuss the possible etiologic factors, anatomic features of the chicken femoral head, biomarkers, and molecular mechanisms relevant to FHN.
Assuntos
Galinhas , Necrose da Cabeça do Fêmur/veterinária , Doenças das Aves Domésticas/patologia , Animais , Biomarcadores , Necrose da Cabeça do Fêmur/genética , Necrose da Cabeça do Fêmur/patologia , Necrose da Cabeça do Fêmur/prevenção & controle , Predisposição Genética para Doença , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/prevenção & controle , Seleção GenéticaRESUMO
Stress has been shown to affect the immune system of turkeys making them more susceptible to bacterial infections. Five-week-old male and female turkeys were treated with 3 intra-muscular injections of dexamethasone (Dex) at 0, 0.5 and 2.0mg/kg body weight. Twenty-four hours after the third injection birds were bled and white blood cell (WBC) differentials and bacteriostatic activity of monocytes were measured. Dex at both 0.5 and 2.0mg/kg decreased phagocytic activity in females only. Bacteriostatic activity was decreased at both concentrations of Dex at 8 and 16 h post-infection in both sexes and was lower in males as compared to females. Total WBC counts were increased in females at both concentrations of Dex whereas male total WBC counts were unaffected. Both males and females had an increase in the heterophil to lymphocyte ratio. Within the same study, replicate pens of turkeys were challenged with intra-air sac inoculation of 100 cfu of Escherichia coli. Isolation of E. coli was significantly increased by both Dex and E. coli challenge, but there were no differences between sexes. These results suggest that stress can compromise the bacteriostatic activity of turkey monocytes and increase bacterial colonization of blood and tissues, potentially affecting food safety.
Assuntos
Dexametasona/farmacologia , Inocuidade dos Alimentos , Imunidade/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Doenças das Aves Domésticas/prevenção & controle , Perus/imunologia , Animais , Infecções Bacterianas/imunologia , Infecções Bacterianas/prevenção & controle , Infecções Bacterianas/veterinária , Feminino , Contagem de Leucócitos/veterinária , Masculino , Monócitos/imunologia , Monócitos/fisiologiaRESUMO
Eggshell membranes (ESM) contain a variety of proteins and peptides which help in the development of embryo and provide protection to it. Many of the peptides and proteins associated with ESM have antimicrobial, immune-modulatory, and adjuvant properties. We hypothesized that the membrane byproducts from egg, provided as posthatch nutritional supplements to chickens, may improve their performance and immunity. To explore its effect, we fed 3 groups of broiler chicks with feed containing 0, 0.2, and 0.4% ESM from d 1 posthatch through 14 d and regular feed thereafter. The birds were individually weighed at the onset of the study and at weekly intervals until the termination at third wk when they were bled and euthanized. The relative weights of liver, spleen, bursa, and heart, hematology profiles, and clinical chemistry variables including serum IgM, IgG, and corticosterone concentrations were measured. The chickens in the ESM treated groups showed a statistically significant increase in BW with no impact on relative organ weights. Compared with controls, the WBC and lymphocyte percentage increased in chickens fed 0.4% ESM whereas the monocyte percentage decreased at both levels of ESM. Except for the serum protein which increased in ESM fed birds no other metabolic clinical chemistry variables showed any significant change. Both IgM and IgG(Y) levels were elevated and corticosterone levels reduced in chickens fed ESM supplemented diets. Our results suggest that ESM supplements during the early phases of growth may improve immunity and stress variables, and enhance their growth performance without any detrimental effect on other physiological parameters.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Galinhas/fisiologia , Dieta/veterinária , Casca de Ovo/química , Imunidade Inata , Ração Animal/análise , Animais , Galinhas/crescimento & desenvolvimento , Galinhas/imunologia , Suplementos Nutricionais/análise , MasculinoRESUMO
Prebiotics consisting of resistant starch may alter intestinal ecology, thus modulating inflammation and increasing intestinal health through increased cecal production of short-chain fatty acids (SCFA). Probiotics may directly alter the intestinal microbiome, resulting in the same effects. We hypothesize that adding prebiotics and probiotics to feed may protect the gut of young chicks under stress. Studies 1, 2, and 3 evaluated treatments in a cold stress (CS) and Escherichia coli (EC) oral challenge to 430 day-old broiler chicks for 3 wk. In study 1, prebiotics were administered as 15% of the diet during the first week only and consisted of the following: Hi-Maize resistant starch (HM), potato starch (PS), or raw potato (RP). In studies 2 and 3, the PS treatment was identical to study 1, and an additional probiotic treatment (PRO) was administered in feed and water. In study 1, PS protected BW during the first week and decreased the mortality of CS/EC-challenged birds during the first week and wk 3, while RP decreased the mortality of warm-brooded birds challenged with EC during the first week. In study 2, PS decreased and PRO increased the main effect mean (MEM) of the first week BW. PS and PRO numerically decreased the feed conversion ratio (FCR) by 23 and 29 points, respectively, in CS/EC-challenged birds with no effects on mortality. In study 3, PS decreased and PRO increased the first week and wk 3 MEM BW. PS numerically increased FCR by 16 points, while PRO decreased FCR by 2 points. Both PS and PRO tended to increase overall mortality, and PRO significantly increased mortality in the CS/EC challenge. These results suggest that the effects of PS may be too variable in this challenge model for further study; however, the PRO treatment improved production values and may have potential as an alternative to antibiotics during the first weeks after hatch.
Assuntos
Ração Animal/análise , Galinhas/fisiologia , Temperatura Baixa/efeitos adversos , Dieta/veterinária , Prebióticos , Probióticos , Animais , Suplementos Nutricionais , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/patologia , Infecções por Escherichia coli/veterinária , Masculino , Solanum tuberosum/química , Amido/química , Amido/farmacologia , Estresse Fisiológico , Fatores de Tempo , Aumento de PesoRESUMO
Bacteriophages are viruses that kill bacteria. They are plentiful in nature; are safe, having no known activity to human or animal cells; and are an attractive alternative to antibiotics. The objectives of this research were to establish an experimental model of colibacillosis induced by indirect exposure to Escherichia coli and to determine if bacteriophage could protect the birds from developing colibacillosis. In study 1 there were 6 treatments with 2 replicate pens of 25 birds. The treatments were control warm brooded; control cold stressed; litter inoculated with E. coli, warm brooded; litter inoculated with E. coli, cold stressed; seeder birds (5 per pen) challenged with E. coli, warm brooded; and seeder birds (5 per pen), cold stressed. The study concluded when the birds were 3 wk of age. Body weights at 1, 2, and 3 wk of age were significantly decreased (P ≤ 0.05) by cold stress, decreased at 1 and 2 wk of age by both the litter and seeder bird treatments compared with the control treatment and by the seeder bird treatment at 3 wk of age. Study 2 consisted of 8 treatments with 2 replicate pens of 20 birds per treatment. The treatments were control, warm brooded; control, cold stressed; litter inoculated with E. coli, cold stressed; and seeder birds (5/pen) challenged with E. coli, cold stressed with and without bacteriophage treatment. In the bacteriophage treatments the bacteriophages were sprayed on the litter. The study was concluded at 3 wk of age. Body weights at 1 wk of age were significantly (P ≤ 0.05) decreased from the control treatment by the seeder bird treatment and were significantly (P ≤ 0.05) higher in all the bacteriophage treatments compared with their matched untreated treatments, except in the control cold stressed treatment. Mortality was significantly (P ≤ 0.05) decreased by bacteriophage in the litter challenged treatment. These data suggest that augmentation of the environment with bacteriophage is a practical and efficacious way to prevent colibacillosis in broiler chickens.
Assuntos
Galinhas , Colífagos/fisiologia , Microbiologia Ambiental , Infecções por Escherichia coli/veterinária , Escherichia coli/virologia , Doenças das Aves Domésticas/prevenção & controle , Animais , Escherichia coli/fisiologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/prevenção & controle , Masculino , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/mortalidade , TemperaturaRESUMO
Clostridial dermatitis (CD) is a production disease of commercial turkeys that is characterized by sudden mortality in market-aged male birds and by lesions that include fluid and air bubbles under the skin of the thigh, breast, and tail area. We have developed a model for CD using dexamethasone (Dex) injection that suggests this disease may be related to stressors during the last stages of turkey production. Male turkeys were provided with control feed and water or with feed supplemented with a commercial yeast extract (YE) product, water supplemented with vitamin D (VD), or the combination. At 6, 11, and 15 wk of age birds were treated with three intramuscular injections of Dex over a 5-day period. Both YE and VD, but not the combination, decreased early mortality. At week 7 mortality was increased by VD, and cellulitis lesions were seen in 7/8 mortalities. Mortality at week 12 was decreased by both YE and the combination of YE and VD, and cellulitis lesions were seen in 8/17 mortalities. There were no significant differences in mortality at week 16. Total mortality was 66 birds, and 23 of these had cellulitis lesions (38%). There were no YE-treated birds with CD lesions; however, 67% of VD-treated birds had CD lesions. This study suggests that feed supplementation with YE may improve the ability of turkeys to withstand the stressors during late production and provide protection against the development of CD; however, high levels of VD supplementation may be detrimental.
Assuntos
Colecalciferol/farmacologia , Infecções por Clostridium/veterinária , Dexametasona/toxicidade , Doenças das Aves Domésticas/prevenção & controle , Dermatopatias Bacterianas/veterinária , Leveduras/metabolismo , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Colecalciferol/administração & dosagem , Clostridium/classificação , Clostridium/isolamento & purificação , Infecções por Clostridium/prevenção & controle , Suplementos Nutricionais , Água Potável , Hospedeiro Imunocomprometido , Imunossupressores/toxicidade , Masculino , Dermatopatias Bacterianas/microbiologia , Dermatopatias Bacterianas/prevenção & controle , PerusRESUMO
Bacteriophages are viruses that kill bacteria. They are plentiful in nature with no known activity in human or animal cells, making them an attractive alternative to antibiotics. The objective of this research was to determine if a coarse or a fine spray of bacteriophage would prevent colibacillosis induced by an intratracheal (IT) challenge with Escherichia coli. Two studies were conducted with 6 treatments: untreated control, birds treated with a spray administration of bacteriophage and not challenged, birds administered bacteriophage IT and not challenged, birds not treated and challenged IT with E. coli, birds sprayed with bacteriophage and IT challenged with E. coli, and birds administered bacteriophage IT and challenged IT with E. coli. There were 3 replicate pens of 10 birds per pen, per treatment, and all treatments were administered at 1 d of age. Study 1 was concluded when the birds were 19 d of age, and study 2 was concluded when the birds were 21 d of age. In both studies, neither a coarse nor a fine spray protected the birds from an IT E. coli challenge; however, when bacteriophage was administered IT there was complete protection. This research demonstrates the necessity for the administration of bacteriophage therapeutics to deliver high bacteriophage titers to the site of a bacterial infection.
Assuntos
Galinhas , Colífagos/fisiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/imunologia , Doenças das Aves Domésticas/imunologia , Infecções Respiratórias/veterinária , Aerossóis/administração & dosagem , Animais , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/prevenção & controle , Masculino , Tamanho da Partícula , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/prevenção & controle , Infecções Respiratórias/imunologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/prevenção & controle , Vacinação/veterináriaRESUMO
Japanese quail selected for divergent corticosterone response to restraint stress were evaluated for their susceptibility to heat stress and challenge with Escherichia coli. These quail lines are designated as high stress (HS), low stress (LS), and the random-bred control (CS) lines. Heat stress (35°C, 8 h/d) began at 24 d until the end of the study at 39 d. Birds were challenged with an aerosol spray containing 2 × 10(9) cfu of E. coli at 25 and 32 d. At 38 d, the surviving birds were necropsied and the intestinal tract was screened for both Salmonella and Campylobacter. Body weights of the CS birds were higher than both HS and LS at 17, 25, and 32 d. At 32 d, there was no difference in mortality between males and females and the CS line had higher mortality compared with the LS line with the HS line being intermediate. At 38 d, females of the CS line that were both heat stressed and challenged had a mortality incidence of 25%, which was significantly higher than male birds of the same line and treatment (5.3%). There was an increased incidence in Salmonella enterica serotype Agona isolation after heat stress, with the LS birds having less isolation than the HS birds. Mean corticosterone levels of male birds were not significantly affected by line, heat stress, or E. coli challenge; however, the LS line subjected to heat stress had one-third the level of the HS line, a difference identical to that seen in the original selection for response to restraint stress.
Assuntos
Coturnix , Infecções por Escherichia coli/veterinária , Temperatura Alta , Restrição Física/veterinária , Estresse Fisiológico , Animais , Coturnix/genética , Coturnix/fisiologia , Feminino , Masculino , Restrição Física/efeitos adversos , Fatores SexuaisRESUMO
A commercial yeast culture feed supplement (YC; Celmanax SCP, Vi-COR, Mason City, IA) was provided to turkeys throughout a 16-wk grow-out to determine if it would prevent the effects of stress on production and pathogen colonization. The YC was provided either continuously at 100 g/t (YC-CS) or intermittently during times of stress at 200 g/t (YC-IS). Birds were stressed with an environmental challenge of Escherichia coli and by transporting them in a vehicle for 3 h after which they were penned in new social groups, without feed or water, for an additional 9 h. Turkeys were transported and challenged at 6, 12, and 16 wk of age to model the movement of birds within a 3-stage housing system. The YC-IS was provided only for the first week after hatch and for a 1-wk period encompassing each challenge. At wk 7 and 9, a decrease in BW of challenged birds was prevented by YC-IS but not YC-CS. There were no significant differences in BW due to either challenge or YC during wk 11 and 13. At wk 16, the challenge decreased BW, but there was no improvement in either of the YC treatments. Overall feed conversion ratio (FCR) was increased by transport/E. coli (P < 0.0001). The YC-CS improved FCR of challenged birds by 21 points, whereas YC-IS improved FCR by 36 points and this effect was significant (P = 0.013). The YC-CS tended to decrease both Salmonella and Campylobacter isolation from the ceca of stressed birds (P > 0.05). The YC-IS also tended to decrease Salmonella isolation (P > 0.05) with no effect on Campylobacter isolation. These data suggest that the practice of transporting turkeys decreases performance and that YC-IS may be more effective than YC-CS for alleviating the effects of this stressor on feed efficiency.
Assuntos
Ração Animal/análise , Infecções por Escherichia coli/veterinária , Estresse Fisiológico , Meios de Transporte , Perus , Leveduras , Animais , Portador Sadio , Dieta/veterinária , Suplementos NutricionaisRESUMO
White striping is the white striation occasionally observed parallel to the direction of muscle fibers in broiler breast fillets and thighs at the processing plant. Broiler breast fillets can be categorized as normal (NORM), moderate (MOD), or severe (SEV) based on the degree of white striping. Histologically, SEV fillets are characterized by the highest degree of degeneration of muscle fibers along with fibrosis and lipidosis when compared with NORM. The present study was undertaken to compare the hematologic and serologic profiles of broilers with NORM and SEV degrees of white striping to get more information on the systemic changes associated with the condition. Day-old male broiler chicks of a commercial strain were grown on the same diet in 6 replicate pens (n = 32 birds/pen). Blood samples (5 mL) were collected from the wing vein of each bird on the day before processing for analyzing hematologic and serologic profiles. At 63 d, the birds were weighed and processed in a commercial inline processing system. Weight of the butterfly fillets, liver, and abdominal fat pad were recorded. Left-side fillets were scored to obtain the degree of white striping for each bird. Representative samples for NORM (n = 24) and SEV (n = 17) categories were selected to compare the hematologic and serologic profiles. The SEV birds had greater (P < 0.05) live, fillet, and liver weights, as well as fillet yield, compared with the NORM birds, but the abdominal fat yield was less (P < 0.05) in SEV birds. The NORM and SEV birds did not show any differences in various hematological parameters, including the differential leukocyte count. Conversely, SEV birds had elevated (P < 0.05) serum levels of creatine kinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. These results suggest that there is no systemic infectious or inflammatory condition associated with a SEV degree of white striping. The elevated serum enzyme levels confirm the muscle damage associated with the degenerative myopathy in SEV birds.
Assuntos
Galinhas , Ácidos Graxos/metabolismo , Doenças Musculares/veterinária , Doenças das Aves Domésticas/sangue , Doenças das Aves Domésticas/fisiopatologia , Animais , Testes Hematológicos/veterinária , Fígado/fisiopatologia , Masculino , Doenças Musculares/sangue , Doenças Musculares/patologia , Doenças Musculares/fisiopatologia , Músculos Peitorais/patologia , Músculos Peitorais/fisiopatologia , Doenças das Aves Domésticas/patologia , Testes Sorológicos/veterináriaRESUMO
We have studied the etiology of turkey osteomyelitis complex (TOC) for the past 20 yr and have determined that this syndrome is caused by the inability of some fast-growing male turkeys to cope with production stressors. Although immunosuppressive viruses have often been associated with susceptibility to gangrenous dermatitis (cellulitis), we hypothesize that production stressors alone can also undermine resistance to opportunistic pathogens by both increasing bacterial translocation from the intestine and disrupting the skin's antimicrobial barrier, resulting in subcutaneous lesions referred to as cellulitis and recently named turkey clostridial dermatitis (CD). Some common characteristics between TOC and CD are that they are both caused by opportunistic bacterial species that are prevalent in the environment and are both most common in adolescent male birds. In both diseases the affected birds are often large, healthy, and from the best-performing flocks. Our TOC studies using dexamethasone immunosuppression result in a high incidence of cellulitis lesions in dead turkeys that were given either Escherichia coli or Staphylococcus aureus respiratory challenges. The natural presence of Clostridium spp. in the poultry intestine and environment suggests that they may also have been concomitant pathogens. We suggest that a useful and repeatable model for CD can be developed by focusing on the ability of stress to increase diuresis and wet litter conditions and undermine both intestinal and cutaneous bacterial resistance in fast-growing male turkeys.
Assuntos
Anti-Inflamatórios/administração & dosagem , Celulite (Flegmão)/veterinária , Infecções por Clostridium/veterinária , Dexametasona/administração & dosagem , Doenças das Aves Domésticas/imunologia , Perus , Animais , Carga Bacteriana/veterinária , Celulite (Flegmão)/epidemiologia , Celulite (Flegmão)/imunologia , Celulite (Flegmão)/microbiologia , Clostridium/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/imunologia , Infecções por Clostridium/microbiologia , Dermatite/epidemiologia , Dermatite/imunologia , Dermatite/microbiologia , Dermatite/veterinária , Modelos Animais de Doenças , Incidência , Masculino , Osteomielite/epidemiologia , Osteomielite/imunologia , Osteomielite/microbiologia , Osteomielite/veterinária , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Estudos RetrospectivosRESUMO
1. The effects of high fat diets and prednisolone treatment were studied to understand the etiology of femoral head separation (FHS) in fast growing broiler chickens. Dietary effects on production parameters such as growth, feed conversion ratio (FCR) and blood chemistry were also measured. 2. Three groups of chickens, consisting of 30 birds each, in two replicate pens, were fed isonitrogenous diets containing 40 (control), 60, or 80 g poultry fat supplements per kg feed. The birds were fed a starter diet containing the fat supplements for the first three weeks, then switched to a grower diet containing the same supplements for the rest of the experimental period. Two groups of birds were also raised with the control diets, but were administered either cholesterol or prednisolone intramuscularly at 30 and 32 days of age to evaluate their effects on FHS incidences. 3. The chickens were euthanised and necropsied at 37 d of age. The presence of femoral head weakness was determined by applying mild pressure on the pelvic joint to cause the growth plate to become detached from its articular cartilage in affected cases. 4. High fat diets did not change FHS incidences, but increased 28 d body weights (BW) and FCR. At 37 d of age the BW differences were not significant but the FCR (gain: feed ratio) remained higher in high fat fed groups. Prednisolone treatment, by contrast, resulted in decreased BW, decreased feed efficiency, increased FHS index, and elevated blood lipid levels. 5. The results suggest that high dietary fats do not affect FHS incidence in broilers. Prednisolone treatment causes hyperlipidaemia and increases FHS index, and may therefore provide a suitable experimental model of FHS pathogenesis in growing chickens.
Assuntos
Doenças Ósseas/veterinária , Galinhas , Dieta Hiperlipídica/efeitos adversos , Cabeça do Fêmur , Doenças das Aves Domésticas/etiologia , Prednisolona/administração & dosagem , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peso Corporal , Doenças Ósseas/etiologia , Colesterol na Dieta/administração & dosagem , Cabeça do Fêmur/patologia , Lâmina de Crescimento/patologia , Masculino , Doenças das Aves Domésticas/patologia , Prednisolona/efeitos adversos , Aumento de PesoRESUMO
1. Effective nutritional approaches to counteract the negative effects of stress may provide food animal producers with useful alternatives to antibiotics. In this study, turkeys were fed on a standard diet, or the same diet supplemented with yeast extract (YE), to determine if YE would improve disease resistance in a stress model. 2. At 16 weeks of age, half of the birds were exposed to a bacterial challenge using a coarse spray of the pen environment. A subset of control and challenged birds was also treated with dexamethasone (Dex) prior to challenge (Dex/challenge). At 18 weeks, another subset was subjected to a 12?h transport stress protocol (Challenge/transport). All birds were bled and necropsied the morning after transport. The numbers and proportions of blood cells and the heterophil oxidative burst activity (OBA) were determined. Serum corticosterone (Cort) levels of male birds were measured using a commercial ELISA kit. Body weight and gain were increased by YE during week 1. 3. YE decreased mortality and bacterial isolation following Dex/challenge only in females. Cort levels in male turkeys were decreased by YE and Dex treatment. OBA was higher in males and in birds given YE and was reduced by challenge and transport. 4. These results suggest there may be gender differences in the turkey stress response and that dietary YE has potential for modulating the impact of stress on innate immunity of turkeys.
Assuntos
Suplementos Nutricionais , Doenças das Aves Domésticas/imunologia , Estresse Fisiológico , Perus/fisiologia , Fermento Seco/administração & dosagem , Ração Animal , Animais , Peso Corporal , Corticosterona/sangue , Dexametasona/administração & dosagem , Dieta/veterinária , Resistência à Doença , Ensaio de Imunoadsorção Enzimática , Escherichia coli , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/veterinária , Feminino , Glucocorticoides/administração & dosagem , Abrigo para Animais , Listeria monocytogenes , Listeriose/imunologia , Listeriose/veterinária , Masculino , Neutrófilos/imunologia , Distribuição Aleatória , Explosão Respiratória , Fatores Sexuais , Meios de Transporte , Perus/microbiologia , Estados UnidosRESUMO
A study was conducted to determine if prior exposure with bacteriophage would limit the ability of the same bacteriophage to treat colibacillosis. There were 5 treatments with 3 replicate pens of 20 birds per pen. The treatments consisted of 1) control, 2) birds treated with bacteriophage at 10 and 17 d of age, 3) birds challenged with Escherichia coli at 17 d of age, 4) birds challenged with E. coli and treated with bacteriophage at 17 d of age, and 5) birds treated with bacteriophage at 10 d of age and challenged with E. coli and treated with bacteriophage at 17 d of age. Colibacillosis was induced by injecting 0.1 mL of E. coli into the thoracic airsac containing 1 x 10(6) cfu. The bacteriophage was administered by i.m. injection of 0.1 mL into the thigh, providing a dose of 6.8 x 10(8) pfu. The study was concluded 14 d after E. coli challenge. Mortality in the birds challenged with E. coli and not treated with bacteriophage was 55% (treatment 3), and bacteriophage therapy significantly (P < or = 0.05) reduced mortality to 8% (treatment 4), which was not significantly (P < or = 0.05) different from the 2 non-E. coli-challenged controls (3%, treatment 1, and 2%, treatment 2). However, mortality in the birds administered bacteriophage before challenge with E. coli and treated with bacteriophage (treatment 5) was 33%, which was not significantly different (P < or = 0.05) from the birds that were challenged with E. coli and untreated (55%, treatment 3). A kinetic in vitro assay of bacteriophage activity found that serum from birds pretreated with bacteriophage (treatment 5) inhibited bacteriophage activity. The IgG levels to the bacteriophage in serum from birds pretreated with bacteriophage (treatment 2) were significantly higher at all dilutions compared with control serum (treatment 1). These data demonstrate that prior exposure to bacteriophage will limit bacteriophage therapeutic efficacy and suggests that the reduced efficacy is due to an immune response to bacteriophage.
Assuntos
Bacteriófagos/fisiologia , Infecções por Escherichia coli/veterinária , Animais , Antibacterianos/uso terapêutico , Galinhas , Enrofloxacina , Escherichia coli/virologia , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/terapia , Infecções por Escherichia coli/virologia , Fluoroquinolonas/uso terapêutico , Masculino , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/terapia , Doenças das Aves Domésticas/virologiaRESUMO
Yeast extracts (YE) contain biological response modifiers that may be useful as alternatives to antibiotics for controlling pathogens in poultry production and mitigating the deleterious effects of production stressors. The objective of the present study was to determine the ability of a commercial dietary YE (Alphamune) to modulate the immune response in male turkey poults challenged with Escherichia coli and subjected to transport stress. Alphamune was added to turkey poult diets at 0, 500, or 1,000 g/ton. Poults were challenged by air sac injection with 60 cfu of E. coli at 1 wk of age. At 3 wk of age, these challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers and percentages, hematological parameters, and clinical chemistry values were determined. Oxidative burst activity of isolated heterophils was measured using stimulation with phorbol myristate acetate and a 2',7'-dichlorofluorescein diacetate assay. Data were analyzed using GLM and least squares means procedures of the SAS program. The numbers and percentages of heterophils in peripheral blood were increased and their oxidative burst activity was stimulated by YE. The stress challenge dramatically increased oxidative burst and this increase was significantly modulated by YE treatment. Serum levels of calcium, phosphorus, and triglycerides were decreased and uric acid levels, erythrocyte numbers, hemoglobin, and hematocrit were increased by YE supplementation. Bacteria were isolated from the air sac and liver of a lower percentage of birds provided with YE. These results suggest that dietary YE has potential as a nonantibiotic alternative for decreasing bacterial pathogens in turkey production.
Assuntos
Suplementos Nutricionais , Infecções por Escherichia coli/veterinária , Estresse Fisiológico/fisiologia , Meios de Transporte , Perus/sangue , Ração Animal , Animais , Dieta/veterinária , Relação Dose-Resposta a Droga , Masculino , Doenças das Aves Domésticas/prevenção & controle , Fatores de Tempo , LevedurasRESUMO
Infectious and metabolic disorders are common in poultry and cause stress, poor performance, and mortality that results in considerable economic loss. Identifying the nature of stress in chickens will assist the development of appropriate measures to improve health and welfare. Acute phase proteins are hepatic proteins, the blood concentrations of which change significantly in the event of many health problems including inflammation and physical injuries. Thus, acute phase proteins are used as nonspecific diagnostic markers for various health disorders. Our previous studies showed that serum ovotransferrin (OVT) is an acute phase protein in chickens. Therefore, in the present study, we investigated whether OVT concentration can be a marker of physiological stress using sera from chickens with different infectious and metabolic disorders. A competitive enzyme immunoassay was developed to measure serum OVT concentrations. The results show that with experimentally induced pulmonary hypertension syndrome and tibial dyschondroplasia, there were no significant changes in OVT levels compared with matched controls. In contrast, when chickens were infected with microbes such as the bacterium Escherichia coli, or protozoan parasites such as Eimeria maxima and Eimeria tenella, there was a significant increase in the levels of OVT in the serum. Chickens with spontaneous autoimmune vitiligo also showed a significant increase in blood OVT levels. These studies suggest that blood OVT concentration is modulated under inflammatory and microbial stress and can therefore be used as a diagnostic marker of infection and inflammation in chickens.
Assuntos
Biomarcadores/sangue , Galinhas , Conalbumina/sangue , Técnicas Imunoenzimáticas/veterinária , Inflamação/veterinária , Doenças das Aves Domésticas/imunologia , Animais , Técnicas Imunoenzimáticas/métodos , Inflamação/sangue , Inflamação/imunologia , Masculino , Doenças das Aves Domésticas/diagnósticoRESUMO
We have hypothesized that stress-induced subclinical infection of turkeys with Listeria monocytogenes may be an overlooked source of processing plant contamination, and we have shown that concurrent Escherichia coli challenge can increase L. monocytogenes colonization. The objective of this study was to determine the effects of dexamethasone (Dex) immunosuppressive treatment and transport stress on the isolation of L. monocytogenes in an E. coli-L. monocytogenes challenge model. Thirteen-week-old male turkeys housed in floor pens were either nonchallenged (NCH) or challenged (CH) by environmental exposure to E. coli and L. monocytogenes Scott A, using both a coarse spray and feed inclusion. One group of both NCH and CH birds was not stressed (NCH-Con and CH-Con, respectively), a second group was treated with Dex during challenge (NCH-Dex and CH-Dex, respectively), and a third group was subjected to a 12-hour transport (Trans) stress protocol at 15 wk of age (NCH-Trans and CH-Trans, respectively). All birds were bled and necropsied the morning after transport. Dexamethasone treatment increased mortality and disease incidence. The CH-Con, CH-Trans, and CH-Dex birds, as well as the NCH-Dex birds, had lowered body weights compared to the NCH-Con. The relative liver and heart weights were increased, and the relative bursal weights were decreased by both NCH-Dex and CH-Dex treatments. The heterophil:lymphocyte ratio, a measure of the stress response, was increased by CH-Trans, NCH-Dex, and CH-Dex. Total erythrocyte counts and hematocrit were decreased by NCH-Trans, CH-Trans, NCH-Dex and CH-Dex. The challenge strain of E. coli was isolated from the organs of a significant number of CH-Dex birds using direct plating and occasionally from CH-Trans birds. Listeria monocytogenes was not isolated from significant numbers of birds using direct plating, but was isolated from the knee or hip synovial tissues of a significant percentage of CH-Dex birds using pre-enrichment cultural methods, and from CH-Trans and CH-Dex birds using real-time PCR detection. These data suggest that L. monocytogenes colonization of processing-age turkeys can be increased by stress, and the organism may be harbored within inapparent infections of turkey synovial tissue.
Assuntos
Infecções por Escherichia coli/veterinária , Listeriose/veterinária , Doenças das Aves Domésticas/microbiologia , Estresse Fisiológico , Perus , Animais , Bolsa de Fabricius/patologia , Dexametasona/toxicidade , Escherichia coli , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/patologia , Listeria monocytogenes , Listeriose/microbiologia , Listeriose/patologia , Fígado/patologia , Masculino , Miocárdio/patologia , Doenças das Aves Domésticas/patologia , Baço/patologia , Meios de TransporteRESUMO
The successful use of virulent (lytic) bacteriophages (phages) in preventing and treating neonatal enterotoxigenic Escherichia coli infections in calves, lambs and pigs has prompted investigation of other applications of phage therapy in food animals. While results have been very variable, some indicate that phage therapy is potentially useful in virulent Salmonella and E. coli infections in chickens, calves and pigs, and in control of the food-borne pathogens Salmonella and Campylobacter jejuni in chickens and E. coli O157:H7 in cattle. However, more rigorous and comprehensive research is required to determine the true potential of phage therapy. Particular challenges include the selection and characterization of phages, practical modes of administration, and development of formulations that maintain the viability of phages for administration. Also, meaningful evaluation of phage therapy will require animal studies that closely represent the intended use, and will include thorough investigation of the emergence and characteristics of phage resistant bacteria. As well, effective use will require understanding the ecology and dynamics of the endemic and therapeutic phages and their interactions with target bacteria in the farm environment. In the event that the potential of phage therapy is realized, adoption will depend on its efficacy and complementarity relative to other interventions. Another potential challenge will be regulatory approval.
Assuntos
Infecções Bacterianas/veterinária , Bacteriófagos/fisiologia , Qualidade de Produtos para o Consumidor , Farmacorresistência Bacteriana , Controle Biológico de Vetores/métodos , Animais , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Bactérias/virologia , Infecções Bacterianas/prevenção & controle , Bovinos , Contagem de Colônia Microbiana/veterinária , Relação Dose-Resposta a Droga , Microbiologia de Alimentos , Humanos , Testes de Sensibilidade Microbiana/veterinária , Aves Domésticas , Suínos , VirulênciaRESUMO
Three lines of turkeys were compared for response to an Escherichia coli challenge followed by transport stress (transport). The turkey lines were a slow-growing line selected for increased egg production (egg line), a fast-growing line selected for increased 16-wk BW (F line), and a commercial line (Comm line). Birds were challenged at 14 wk of age with an air sac injection of 5,000 to 10,000 cfu of E. coli. At 8 d postchallenge, birds were subjected to a transport stress procedure that included 12 h of holding time in a transport vehicle. The following morning all birds (n = 10 to 19 birds/line) were bled. Whole blood was analyzed using the Cell-Dyn 3500 blood analysis system (Abbott Diagnostics), and serum chemistry was measured using the Express Plus analyzer (Ciba-Corning Diagnostics Corp.). Transport significantly decreased the levels of hematocrit, hemoglobin, mean cell volume, mean corpuscular hemoglobin, glucose, triglycerides, cholesterol, phosphorus, iron, albumin, and alkaline phosphatase (AP) and increased the levels of uric acid, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, and creatine kinase. Line differences were variable, but the levels of both iron and AP were least in the fastest-growing Comm line birds and greatest in the slowest-growing egg-line birds with intermediate values in the F line. Iron and AP were also the only parameters influenced by sex, with males having greater levels of both compared with females. The creatine kinase levels were more than 6-fold greater in transported Comm line birds, and iron levels of transported Comm males were 3-fold less than controls. Previously, the growth rate of these lines was positively correlated with increased heterophil to lymphocyte ratios and susceptibility to colibacillosis. The differences seen in the Comm line for these commonly measured blood parameters suggest that they may be useful for profiling flocks to determine their response to transport stress and feed withdrawal.