Campylobacter spp. are frequently carried by poultry, but they are not believed to cause significant disease in these animals. Modern poultry breeds have been selected to grow rapidly under intensive conditions, but recently, consumers have moved toward purchasing birds produced in higher welfare, free-range or organic systems. Birds reared in these systems tend to be a slower growing breed and are fed a different diet. Birds reared in such systems are stocked at a lower density compared with the standard conventional broilers, and they have access to environmental enrichment, such as perches. In previous research, these slower growing birds have been shown to have different levels of Campylobacter carriage in commercial rearing conditions, but the reasons for, and effect of, these different levels are unknown; is it the bird breed, diet, or environmental conditions? In this study, experimental flocks of fast- and slow-growing breeds of broiler chickens were reared to a standard commercial slaughter weight, with their weight gain being measured during the growing period. At 21 days, birds were either infected with Campylobacter jejuni or given a placebo as control. Cohorts of birds were euthanatized at various intervals, and samples were taken for examination for Campylobacter. The fast-growing birds gained weight more rapidly than the slow-growing birds. By 2 days postinfection (dpi), C. jejuni was detected in the caeca and by enrichment from the liver and spleen samples from both breeds of birds. Low-level colonization persisted in the spleen and liver samples but was undetectable by 28 dpi. Fast- and slow-growing birds did not show detectably different levels of Campylobacter carriage. Infection with C. jejuni affected the incidence of hock marks and pododermatitis in both breeds of birds, but the differences were greater with the fast-growing breed compared with the uninfected control birds. In addition, the incidence of pododermatitis was significantly higher in Campylobacter-positive fast-growing birds than in their slower-growing counterparts. The results show that infection with Campylobacter can have an indirect welfare effect on birds via increased incidence of hock marks and pododermatitis.
La infección por Campylobacter muestra diferentes comportamientos en pollos de engorde de crecimiento rápido y lento.
La bacteria Campylobacter spp. está presente frecuentemente en las aves comerciales, pero se cree que no causa una enfermedad significativa en estas aves. Las razas modernas de aves de corral han sido seleccionadas para crecer rápidamente bajo condiciones intensivas, pero recientemente, los consumidores se han desplazado hacia la compra de las aves producidas en sistemas de crianza al aire libre con mayor bienestar y de tipo orgánico. Las aves criadas en estos sistemas generalmente son razas de crecimiento más lento y son alimentadas con una dieta diferente. Las aves criadas en estos sistemas se alojan con una densidad más baja en comparación con los pollos convencionales estándar, y tienen acceso a medio ambiente enriquecido como perchas. En investigaciones anteriores, estas aves de crecimiento más lento han demostrado que tienen diferentes niveles de la presencia de Campylobacter en condiciones de crianza comercial, pero las razones y los efectos de estos distintos niveles no se conocen. ¿Esto estará relacionado con la raza de ave, la dieta, o con las condiciones ambientales? En este estudio, se criaron parvadas experimentales de razas de crecimiento rápido y lento de pollos de engorde a un peso final para procesamiento estándar, con el registro de su aumento de peso durante el período de crecimiento. A los 21 días, las aves fueron infectadas ya sea con Campylobacter jejuni o se les administró un placebo como control. Se sacrificaron grupos cohortes de aves en
