Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 299
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Int J Biometeorol ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38884796

RESUMO

We assessed newborn lambs from two hair-coat sheep breeds, the black Santa Ines (n = 29) and white Dorper (n = 26), to determine how they behaviourally and physiologically respond to the prevailing thermal conditions in an equatorial semi-arid environment. Measurements of hair-coat surface temperature, rectal temperature and the lambs' exposure to sun were recorded across the first 24 h of life every hour, after the lambs had received colostrum. Lambs and ewes were kept in a lambing pen and could freely move between a shaded area or be exposed to sun. During the study period, the air temperature ranged between 20 ºC and 34 ºC. When exposed to sun, lambs and ewes could experience as much as 1200 W m-2 of solar irradiance. Santa Ines lambs exhibited higher (highest density interval at 95%, HDI) hair-coat surface temperatures than did Dorper lambs. Overall, both Santa Ines and Dorper lambs sustained homeothermy, with a mean rectal temperature ranging from 38.7 ºC to 39.1 ºC between night and daytime phase, and a mean amplitude of ~ 0.8 ºC. Nevertheless, from 10:00 to 15:00, some lambs were found to be moderately hyperthermic. Five Santa Ines and three Dorper lambs had rectal temperatures above 40 ºC, and one Santa Ines lamb, while exposed to sun, had a rectal temperature of 41.3 ºC. Over this time period, lambs were more likely to move to shade (HDI at 95%). From 00:00 to 06:00, despite the air temperature being lower than the hair-coat surface, favouring high rates of sensible heat loss to the environment, no lamb exhibited signs of hypothermia (rectal temperature < 37.5 ºC). In conclusion, haired newborn lambs coped well with high levels of radiant heat during the daytime and lower temperatures at night. However, providing access to shade during the daytime is important to improve the welfare of newborn lambs delivered in equatorial semi-arid regions.

2.
Rhinology ; 2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39058315

RESUMO

BACKGROUND: This randomised, double-blind, placebo-controlled, parallel-group, 52-week Phase III study (MERIT; NCT04607005) assessed mepolizumab efficacy and safety in patients with chronic rhinosinusitis with nasal polyps (CRSwNP)/eosinophilic CRS (ECRS) in Japan, Russia, and China, for which data are limited. METHODOLOGY: Eligible patients (enrolled at 60 centres) had blood eosinophil count >2%, endoscopic bilateral NP score ≥5, nasal obstruction visual analogue scale (VAS) score >5, ≥2 sinonasal symptoms, and either previous sinus surgery or systemic corticosteroid use/intolerance. Patients were randomised (1:1) to receive mepolizumab 100 mg subcutaneously or placebo every 4 weeks, plus standard of care. Co-primary endpoints: change from baseline in total endoscopic NP score (ENPS) (Week 52) and nasal obstruction VAS score (Weeks 49-52). Post hoc analyses conducted in a modified intent-to-treat (mITT) population excluded patients from two study sites, related to Good Clinical Practice violations by the Site Management Organisation overseeing these sites. These were considered the primary efficacy analyses. RESULTS: In the mITT population, mepolizumab (n=80) versus placebo (n=83) significantly improved nasal obstruction VAS score from baseline to Week 49-52 and was associated with a trend of total ENPS improvements at Week 52. Mepolizumab/placebo on-treatment adverse events (AEs) occurred in 68/84 and 65/85 patients in the safety population (treatment-related AEs: 2/84 and 5/85, respectively), and on-treatment serious AEs in 0/84 and 4/85 patients, respectively (no fatalities reported). CONCLUSIONS: Mepolizumab was effective and well-tolerated in patients with CRSwNP/ECRS from Japan, Russia, and China.

3.
Anim Genet ; 50(1): 92-96, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30426519

RESUMO

White bass (Morone chrysops), striped bass and their interspecific hybrid are important game fishes, whereas the hybrid striped bass is an important aquaculture species in the US. Numerous state, federal and private hatcheries, therefore, rear these species for stocking purposes as well as for food fish. Although striped bass populations (both wild and domesticated) have been extensively evaluated, relatively little effort has been directed toward the study and improvement of white bass. In this study, we developed SNP resources to examine the genetic relationships among a long-term domesticated white bass line and five potential founder stocks for selective breeding collected from drainages in Arkansas, Texas and Alabama. Using genotyping-by-sequencing, we generated 13 872 genome-wide SNP loci across the six populations. Stringent filtering of SNP-calling parameters identified 426 informative SNP loci. Population genetic and structure analyses using these loci revealed only moderate genetic differentiation between populations (global Fst  = 0.083) and indicated two major genetic clusters. A final 57-SNP assay was successfully designed and validated using the MassARRAY system. The developed SNP panel assigned 96 additional genotyped individuals to their population of origin with 100% accuracy. The SNP resources developed in this study should facilitate ongoing efforts in selective breeding and conservation of white bass.


Assuntos
Bass/genética , Genética Populacional , Polimorfismo de Nucleotídeo Único , Alabama , Animais , Aquicultura , Arkansas , Cruzamento , Domesticação , Genótipo , Filogenia , Texas
4.
J Public Health (Oxf) ; 40(3): e320-e327, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29253185

RESUMO

Introduction: The transition to university is a potentially influential time upon students' drinking behaviour. This study explored the nature of activities and alcohol-related content in marketing materials from student-led societies and local businesses provided to students, at a university freshers' fair in the UK. Methods: All marketing materials handed out at the fair were collected across the 5-day event in September 2015. Written and visual content was analysed using a summative qualitative content analysis. Results: Most student-led societies promoted social events they were hosting (n = 530), most of which took place in a drinking venue or referred to drinking (n = 335). Only four explicitly alcohol-free events were promoted. Student-led societies also promoted activities relating to their interest, e.g. sports training (n = 519), a small proportion of which had references to drinking and drinking venues (n = 54). Three societies provided promotional handouts from local bars or nightclubs. Local bars, pubs and nightclubs promoted events they hosted (n = 81) as well as alcoholic drink promotions (n = 79) and alcohol branded advertising (n = 22), albeit infrequently for the latter. Conclusions: In the first week of university, students are exposed to alcohol-related events, promotions and advertising, which may act as an incentive to participate in drinking.


Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Bebidas Alcoólicas , Marketing , Estudantes , Universidades , Humanos , Marketing/estatística & dados numéricos , Estudantes/psicologia , Estudantes/estatística & dados numéricos , Reino Unido
7.
J Nerv Ment Dis ; 204(6): 415-20, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26915017

RESUMO

Twenty years ago, slightly after the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition was published, we predicted the characteristics of the future Diagnostic and Statistical Manual of Mental Disorders (fifth edition) (). Included in our predictions were how many diagnoses it would contain, the physical size of the Diagnostic and Statistical Manual of Mental Disorders (fifth edition), who its leader would be, how many professionals would be involved in creating it, the revenue generated, and the color of its cover. This article reports on the accuracy of our predictions. Our largest prediction error concerned financial revenue. The earnings growth of the DSM's has been remarkable. Drug company investments, insurance benefits, the financial need of the American Psychiatric Association, and the research grant process are factors that have stimulated the growth of the DSM's. Restoring order and simplicity to the classification of mental disorders will not be a trivial task.


Assuntos
Manual Diagnóstico e Estatístico de Transtornos Mentais , Declarações Financeiras/economia , Transtornos Mentais/classificação , Transtornos Mentais/diagnóstico , Declarações Financeiras/tendências , Apoio Financeiro , Previsões , Humanos , Transtornos Mentais/psicologia
13.
J Wound Care ; 24 Suppl 9: S4-S12, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26352284

RESUMO

OBJECTIVE: Negative pressure wound therapy (NPWT) has previously been shown to be effective in closing diabetic foot wounds that have undergone amputation over a 16-week period. For patients with plantar foot wounds, NPWT is a key therapy. An alternative NPWT with and without a novel soft, flexible port system needs to be evaluated for its comparable efficacy. Our objective was to show the non-inferiority of an alternative negative pressure system, and in a small subset, a novel foam dressing system. METHOD: We performed a single centre prospective study of patients with diabetes undergoing open bone resection in the foot for acutely infected wounds. Wounds were treated with NPWT/soft port technology (SPT), for 112 days or until primary closure or the wound was deemed ready for delayed primary closure. Rate of closure and quality of life were analysed. A previously published cohort was used as a control. RESULTS: Of the 30 patients initially recruited, 29 met eligibility requirements and had NPWT applied a median of 2 days postoperatively. There were seven patients (24%) who had delayed primary closure (mean=58 days) and 52% had sufficient progress to change in treatment (15/29; mean=62 days). Only one patient reached the 112-day mark without sufficient progress to be closed. The primary method of delayed primary closure was split-thickness skin graft. There was a reduction in wound area 56.3% (initial mean area=17.4cm(2) to final mean area=7.6 cm(2); p=0.001) at the end of treatment (mean=58.7 days) reduced to 4.3cm(2) a 67.2% reduction (p=0.004) at the end of study (112 days). CONCLUSION: The alternative NPWT and the soft port technology was well tolerated and effective in the population in aggregate. There was no inferiority between the two technologies. The aggregate closure or progression to be ready for closure rate of 75% at 69 days compares very favourably with previously published data for NPWT in this population of 56% at 56 days (range: 26-92 days). Both cohorts did significantly better than previously published standard of care closure rates of 39% at 77 days. DECLARATION OF INTEREST: J.C. Lantis is a paid consultant for Smith & Nephew, Acelity, Macrocure and Manukamed. This trial as supported by an institutional grant to St Luke's and Roosevelt Hospital sponsored by Smith & Nephew. The outcome of the trial had no bearing on the condition of the grant. No investigator holds an equity position in Smith & Nephew. C. Gendics is a paid consultant of Acelity.

14.
Int J Biometeorol ; 58(1): 41-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23417331

RESUMO

Heat stress can limit the activity time budget of ungulates due to hyperthermia, which is relevant for African antelopes in ecosystems where temperature routinely increases above 40 °C. Body size influences this thermal sensitivity as large bodied ungulates have a lower surface area to volume ratio than smaller ungulates, and therefore a reduced heat dissipation capacity. We tested whether the activity pattern during the day of three antelope species of different body size-eland, blue wildebeest and impala-is negatively correlated with the pattern of black globe temperature (BGT) during the day of the ten hottest days and each season in a South African semi-arid ecosystem. Furthermore, we tested whether the larger bodied eland and wildebeest are less active than the smaller impala during the hottest days and seasons. Our results show that indeed BGT was negatively correlated with the diurnal activity of eland, wildebeest and impala, particularly during summer. During spring, only the activity of the larger bodied eland and wildebeest was negatively influenced by BGT, but not for the smallest of the three species, the impala. We argue that spring, with its high heat stress, coupled with poor forage and water availability, could be critical for survival of these large African antelopes. Our study contributes to understanding how endothermic animals can cope with extreme climatic conditions, which are expected to occur more frequently due to climate change.


Assuntos
Antílopes/fisiologia , Temperatura Alta , Atividade Motora , Estresse Fisiológico , Animais , Tamanho Corporal , Ritmo Circadiano , Clima , Estações do Ano , África do Sul
15.
Animal ; 18(5): 101143, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38640782

RESUMO

Methionine (Met) supplementation is common practice in broilers to support nutrition, yet there are gaps in the understanding of its role in systemic physiology. Furthermore, several different Met sources are available that may have different physiological effects. This study evaluated the mode of action of Met deficiency (no Met-supplementation) and supplementation (0.25% DL- or L-Met, 0.41% liquid methionine hydroxy analog-free acid (MHA-FA)), and of Met source (DL-, L- or MHA-FA) in broiler chickens, via host transcriptomics. Biological pathway activation modeling was performed to predict the likely phenotypic effects of differentially expressed genes (DEGs) in tissue samples from the jejunum, liver and breast obtained at 10, 21 and 34/35 d of age from three experiments in a combined analysis. Animal performance data showed that Met deficiency reduced BW, daily BW gain, daily feed intake, and breast yield, and increased feed conversion ratio in all experiments (P < 0.05). Effects of Met deficiency on gene expression were least evident in the jejunum and most evident in the liver and breast, as evidenced by the number of DEG and activated pathways. Activated pathways suggested Met deficiency was associated with inhibited protein turnover, gut barrier integrity, and adaptive immunity functions in the jejunum, that predicted reduced breast yield. There was an interaction with age; in Met-deficient birds, there were 333 DEGs in the jejunum of starter vs finisher birds suggesting young birds were more sensitive to Met deficiency than older birds. In the liver, Met deficiency activated pathways associated with lipid turnover, amino acid metabolism, oxidative stress, and the immune system, whereas in breast, it activated pathways involved in metabolic regulation, hemostasis, the neuronal system, and oxidative stress, again predicting a negative impact on breast yield. In the starter phase, supplementation with DL-Met compared to MHA-FA inhibited gamma-aminobutyric acid activity and oxidative stress in breast tissue. When data from all tissues were integrated, increased expression of a liver gene (ENSGALG00000042797) was found to be correlated with the expression of several genes that best explained variation due to the Met deficiency in jejunum and breast muscle. Some of these genes were involved in anti-oxidant systems. Overall, the findings indicate that impaired growth performance due to Met deficiency results from an array of tissue-specific molecular mechanisms in which oxidative stress plays a key systemic role. Young birds are more sensitive to Met-deficiency and DL-Met was a preferential source of Met than L- or MHA-FA during the starter phase.


Assuntos
Ração Animal , Galinhas , Suplementos Nutricionais , Fígado , Metionina , Animais , Galinhas/genética , Galinhas/fisiologia , Metionina/deficiência , Metionina/metabolismo , Metionina/administração & dosagem , Ração Animal/análise , Suplementos Nutricionais/análise , Fígado/metabolismo , Transcriptoma , Jejuno/metabolismo , Dieta/veterinária , Masculino , Fenômenos Fisiológicos da Nutrição Animal , Perfilação da Expressão Gênica/veterinária
16.
J S Afr Vet Assoc ; 2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-37358315

RESUMO

Selection of an effective drug combination to immobilise African lions (Panthera leo) requires balancing immobilisation effectiveness with potential side effects. We compared the immobilisation effectiveness and changes to physiological variables induced by three drug combinations used for free-ranging African lions. The lions (12 animals per drug combination) were immobilised with tiletamine-zolazepam-medetomidine (TZM), ketamine-medetomidine (KM) or ketamine-butorphanol-medetomidine (KBM). Induction, immobilisation, and recovery were timed, evaluated using a scoring system, and physiological variables were monitored. The drugs used for immobilisation were antagonised with atipamezole and naltrexone. The quality of induction was rated as excellent for all drug combinations and induction times (mean ± SD) did not differ between the groups (10.54 ± 2.67 min for TZM, 10.49 ± 2.63 min for KM, and 11.11 ± 2.91 min for KBM). Immobilisation depth was similar over the immobilisation period in the TZM and KBM groups, and initially light, progressing to deeper in lions administered KM. Heart rate, respiratory rate and peripheral arterial haemoglobin saturation with oxygen were within the expected range for healthy, awake lions in all groups. All lions were severely hypertensive and hyperthermic throughout the immobilisation. Following antagonism of immobilising drugs, lions immobilised with KM and KBM recovered to walking sooner than those immobilised with TZM, at 15.29 ± 10.68 min, 10.88 ± 4.29 min and 29.73 ± 14.46 min, respectively. Only one lion in the KBM group exhibited ataxia during recovery compared to five and four lions in the TZM and KM groups, respectively. All three drug combinations provided smooth inductions and effective immobilisations but resulted in hypertension. KBM had an advantage of allowing for shorter, less ataxic recoveries.

17.
Poult Sci ; 101(3): 101656, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35016048

RESUMO

Repeated serial in vitro passage of Histomonas meleagridis, the etiological agent of histomoniasis (blackhead) of turkeys, was demonstrated to markedly achieve attenuation and reduction of virulence as compared to the original wild-type isolate. Four experiments were performed to evaluate the route (oral vs. intracloacal) and age (day-of-hatch vs. d 14) for administration of attenuated H. meleagridis isolates as vaccine candidates against homologous or heterologous wild-type challenge. Attenuated H. meleagridis were developed from 2 different strains (Buford strain originating in Georgia; PHL2017 strain originating in Northwest Arkansas). Buford P80a (passage 80, assigned as isolate lineage "a" following repeated passage) was selected as the primary vaccine candidate and was evaluated in Experiments 1-3. Experiment 4 evaluated selected candidates of attenuated PHL2017 (P67, P129) and Buford (P80a, P200a, P138b, P198c) strains against Buford wild-type challenge. As has been demonstrated previously, wild-type H. meleagridis cultures administered orally after 1 day of age were not infective in the current studies, but infection with wild-type cultures could be induced orally at day-of-hatch. Infection was effectively achieved via the intracloacal route at day-of-hatch and in older turkeys (d 21, d 28-29, d 35). Intracloacal inoculation of turkeys with the attenuated passaged isolates as vaccine candidates at d 14 was shown to produce significant (P < 0.05) protection from mortality, reduction in body weight gain, as well as reduction in hepatic and cecal lesions in these experiments following challenge with either the homologous wild-type isolate or from a wild-type strain obtained years later from a geographically disparate area of the United States. Inoculation with the attenuated H. meleagridis isolates at day-of-hatch, either orally or cloacally, did not produce significant protection against subsequent wild-type challenge. While offering significant protection with minimal vaccine-related negative effects, the protection from cloacal vaccine administration was neither significantly robust nor encouraging for industry application using the methods evaluated in the present manuscript since mortalities and lesions were not completely reduced which could thereby potentially allow transmission from residual infection and shedding within a flock.


Assuntos
Doenças das Aves Domésticas , Infecções Protozoárias em Animais , Vacinas Protozoárias , Trichomonadida , Animais , Galinhas , Doenças das Aves Domésticas/prevenção & controle , Infecções Protozoárias em Animais/prevenção & controle , Perus
18.
Avian Dis ; 55(3): 346-9, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22017029

RESUMO

Experiments were conducted to determine whether chukar partridge (Alectoris chukar) chicks would develop protective immunity after inoculation with coccidia. Young chukar chicks in battery cages inoculated with 100 or more oocysts of Eimeria kofoidi or Eimeria legionensis had significant protection at challenge 4 wk later, as measured by greatly reduced oocyst shedding and improved weight gain as compared with unvaccinated, challenged controls. However, when birds were housed in litter pens and vaccinated by various regimens (including two species of chukar coccidia at 100/dose), coccidiosis rapidly spread through all treatments and caused significant mortality. Vaccination with Coccivac-T or with 100 oocysts of Eimeria dispersa did not prevent mortality resulting from accidental contamination, and feed treatment with a Lactobacillus competitive-exclusion product had no benefit. Most if not all of the mortality was from E. kofoidi. This study illustrated the natural fecundity of chukar coccidia in a floor-pen environment where multiplication rate and reinfection combine to produce clinical disease from a small original exposure. Further, these results cast doubt on the potential use of low doses of live oocysts as a vaccine in the chukar partridge.


Assuntos
Coccidiose/veterinária , Eimeria/fisiologia , Galliformes , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/imunologia , Vacinação/veterinária , Animais , Coccidiose/imunologia , Coccidiose/prevenção & controle , Eimeria/crescimento & desenvolvimento , Lactobacillus , Oocistos/fisiologia , Doenças das Aves Domésticas/imunologia , Vacinas Protozoárias/administração & dosagem , Especificidade da Espécie
19.
Avian Dis ; 55(1): 59-64, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21500637

RESUMO

To determine whether chemotherapeutic compounds available for use in domestic poultry are effective at controlling coccidiosis in northern bobwhites (Colinus virginianus), we tested 13 chemotherapeutic anticoccidials including amprolium (250 parts per million [ppm]), clopidol (125 ppm), diclazuril (1 ppm and 2 ppm), decoquinate (30 ppm), lasalocid (120 ppm), monensin (90 ppm), narasin/nicarbazin (36/36 ppm), robenidine (33 ppm), roxarsone (50 ppm), sulfadimethoxine/ ormetoprin (125/75 ppm), salinomycin (60 ppm), semduramicin (25 ppm), and zoalene (125 ppm and 150 ppm). Three tests were conducted using two replicates of 10 birds each: Infected, unmedicated controls and medicated birds were challenged with 1 x 10(6) oocysts of a field isolate consisting primarily of Eimeria lettyae. Subsequently, we tested clopidol, lasalocid, salinomycin, diclazuril (1 ppm), and monensin against mixed-species field isolates containing E. lettyae, E. dispersa, E. colini, or all. Weight gain, gross intestinal lesions, severity of diarrhea, and feed conversion ratio (FCR) 6 days postinfection were recorded. Lesion score, as previously reported, was unreliable as a measure of severity of infection in comparison with weight gain, fecal scores, and FCR. Excellent to good efficacy was found in clopidol, decoquinate, diclazuril (1 ppm and 2 ppm), and in lasalocid, narasin and nicarbazin, robenidine, sulfadimethoxine/ormetoprin, and zoalene (150 ppm). Marginal protection was found using monensin, salinomycin, semduramicin, or a roxarsone/semduramicin combination. Amprolium, roxarsone, and zoalene (125 ppm) were ineffective at controlling coccidia. Two of the six isolates tested against diclazuril 1 ppm and clopidol demonstrated a high degree of resistance, but none of the six isolates was resistant to lasalocid. Four of the eight isolates showed mild to moderate, and moderate to high, resistance against monensin and salinomycin, respectively. These findings indicate that several available compounds are effective at controlling coccidiosis in bobwhites.


Assuntos
Coccidiose/veterinária , Coccidiostáticos/uso terapêutico , Doenças das Aves Domésticas/prevenção & controle , Codorniz , Ração Animal , Animais , Coccidiose/prevenção & controle , Eimeria , Metabolismo Energético , Aumento de Peso/efeitos dos fármacos
20.
Avian Dis ; 65(1): 132-137, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-34339132

RESUMO

Necrotic enteritis (NE) is a common disease that causes great economic loss to the broiler industry due to mortality and reduced performance. Although Clostridium perfringens (CP) is a necessary component of this disease, coccidia species are a well-defined predisposing factor that exacerbates the condition. Different Eimeria species have been reported to influence NE to different degrees. In a pair of experiments, six different Eimeria species were evaluated in the presence and absence of C. perfringens. Male broiler chicks were housed in battery cages for the duration of both experiments. Feed conversion, body weight gain, and NE mortality were reported in both experiments. Experiment 1 challenged birds with E. maxima, E. acervulina, E. tenella, E. necatrix, and E. brunetti at day 13 and subsequently inoculated birds with CP on days 18, 19, and 20. In the second experiment, E. maxima, E. acervulina, E. tenella, and E. praecox were inoculated on day 15 and challenged with CP on days 17, 18, 19, 20, 21, and 22 of the experiment. In the first experiment, E. acervulina, E. brunetti, E. maxima, and E. necatrix with the addition of CP all stimulated necrotic enteritis mortality. In the second experiment, E. praecox had minimal impact on performance during the challenge (14-23 days) while E. maxima + CP decreased body weight gain and increased mortality compared to the CP alone control. Eimeria maxima had the highest mortality (21.9%) in this experiment followed by E. acervulina (6.3%). The remaining Eimeria with added CP in the second experiment did not induce NE mortality. While the challenge with CP alone did not induce mortality, feed conversion was increased compared to the unchallenged control group. When using isolated Eimeria species in these experiments, disturbances created by E. brunetti and E. maxima resulted in the most-severe challenges. These experiments highlight the NE risk of these species of Eimeria and give insight into how other species interact with the host in a controlled CP challenge model.


Artículo regular­Efecto de diferentes especies de Eimeria con Clostridium perfringens sobre los parámetros de rendimiento y la inducción de enteritis necrótica clínica en pollos de engorde. La enteritis necrótica (NE) es una enfermedad común que causa grandes pérdidas económicas a la industria del pollo de engorde debido a la mortalidad y a la reducción del rendimiento. Aunque Clostridium perfringens (CP) es un componente necesario de esta enfermedad, las especies de coccidia son un factor predisponente bien definido que agrava la enfermedad. Se ha informado que diferentes especies de Eimeria influyen en la enteritis necrótica en diferentes grados. En un par de experimentos, se evaluaron seis especies diferentes de Eimeria en presencia y ausencia de C. perfringens. Pollos de engorde machos se alojaron en jaulas en batería durante la duración de ambos experimentos. En ambos experimentos se analizaron la conversión alimenticia, el aumento de peso corporal y la mortalidad por enteritis necrótica. En el Experimento 1 se desafió a las aves con E. maxima, E. acervulina, E. tenella, E. necatrix y E. brunetti en el día 13 y posteriormente se inoculó a las aves con C. perfringens en los días 18, 19 y 20. En el segundo experimento, E. maxima, E. acervulina, E. tenella y E. praecox se inocularon en el día 15 y se desafiaron con C. perfringens en los días 17, 18, 19, 20, 21 y 22 del experimento. En el primer experimento, E. acervulina, E. brunetti, E. maxima y E. necatrix junto con C. perfringens estimularon la mortalidad por enteritis necrótica. En el segundo experimento, E. praecox tuvo un impacto mínimo en el rendimiento durante el desafío (14 a 23 días) mientras que el tratamiento de E. maxima + C. perfringens disminuyó el aumento de peso corporal y aumentó la mortalidad en comparación con el control con solamente C. perfringens. Eimeria maxima tuvo la mayor mortalidad (21.9%) en este experimento seguida por E. acervulina (6.3%). El resto de las especies de Eimeria junto con C. perfringens en el segundo experimento no indujeron mortalidad por enteritis necrótica. Si bien el desafío con C. perfringens no solo no indujo mortalidad, sino que la conversión alimenticia aumentó en comparación con el grupo de control no desafiado. Cuando se utilizaron especies de Eimeria aisladas en estos experimentos, los problemas creados por E. brunetti y E. maxima resultaron en los desafíos más severos. Estos experimentos destacan el riesgo por enteritis necrótica con estas especies de Eimeria y dan una idea de cómo otras especies interactúan con el hospedador en un modelo de desafío con C. perfringens controlado.


Assuntos
Galinhas , Infecções por Clostridium/veterinária , Coccidiose/veterinária , Eimeria/fisiologia , Enterite/veterinária , Necrose/veterinária , Doenças das Aves Domésticas , Animais , Infecções por Clostridium/microbiologia , Clostridium perfringens/fisiologia , Coccidiose/parasitologia , Enterite/microbiologia , Enterite/parasitologia , Masculino , Necrose/microbiologia , Necrose/parasitologia , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/parasitologia , Distribuição Aleatória , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA