The effect of furnished cages on the immune response of laying hens under social stress

Abstract

The aim of the study was to examine the effects of cage furnishing and social stress on some lymphoid organ weight and innate, cell-mediated, and humoral immune responses in laying hens. Sixty-four chickens were used. The chickens were divided into 2 groups; one of the groups was reared in furnished cages (RFC) and the other was reared in conventional cages (RCC). In wk 17, social stress was applied. Heterophil and lymphocyte percentages; liver, spleen, thymus, and bursa of Fabricius weights; phagocytic activity; oxidative burst and chemotaxic activity of heterophil; CD4+ and CD8+ cell proportions; and antibody production were measured. The effect of rearing methods was significant on heterophil, lymphocyte percentage, heterophil/lymphocyte (H/L) ratio, and antibody production. Heterophil percentage and H/L ratio were lower (P=0.001, P=0.001, respectively), and antibody production was higher (P=0.003) in RFC hens compared to RCC hens. The main effect of social stress was also significant on heterophil, lymphocyte percentages, and H/L ratio. Heterophil percentage was higher (P=0.049); H/L ratio tended to be higher (P=0.068); and lymphocyte percentage tended to be lower (P=0.072) due to stress. In addition, thymus and bursa of Fabricius weights tended to be lower (P=0.073 and P=0.074, respectively) in stressed hens. There were significant interactions between rearing methods and social stress on oxidative burst, chemotaxic activity, and CD4+ and CD8+ proportion (P=0.001, P=0.004, P=0.054, and P=0.001, respectively). These parameters were significantly higher in RFC hens, when they were exposed to stress. On the other hand, they did not differ in RCC or unstressed RFC hens. These results indicated that cage furnishing positively affected heterophil functions, CD4+ and CD8+ cell proportions, and antibody production. Therefore, we suggest that cage furnishing, which is recommended for improving the welfare of animals, is also beneficial for improving the immune response of hens under the stress condition.

Frequency and Duration of Fecal Shedding of Salmonella Enteritidis by Experimentally Infected Laying Hens Housed in Enriched Colony Cages at Different Stocking Densities

“…Any disruptions of the complex regulatory circuitry, which coordinates immune responses, could reduce the effectiveness of host defenses against infection (63, 64). Stronger antibody and cellular immune responses were mounted by laying hens housed in enriched colony cages than by hens in conventional cages when subjected to social stress (65). Differences between housing systems and stocking densities in the frequency of colonization of the spleen (an important secondary lymphatic organ) in experimentally infected hens are consistent with a stress-mediated explanation (57, 60).…”

Evaluation of Floor vs. Cage System of Broiler Chickens Reared in Three Different Areas of Enclosed Houses on Productive and Physiological Performance

“…However, rearing area insignificantly affected lymphoid organs, while titer response in birds placed in vent and middle area significantly increased for birds placed in fan area. In this context, Matur et al (2015) showed that thymus and Bursa of Fabricius weights tended to be lower in stressed hens. Data revealed that titer response insignificantly affected due to housing system, while the highest titer response was detected for birds placed in vent and middle area as compared with birds placed in fan area.…”

Minimal Effects of Rearing Enrichments on Pullet Behaviour and Welfare

“…However, there were no differences in faecal corticosterone metabolites, and the differences in system use were equivalent between rearing groups after four weeks in the new housing environment [13]. Comparisons between pullets reared in standard cages or cages with perches, strings, a dust bathing area and a nest box showed that these rearing enrichments improved immune responses under an imposed social stressor, including lowered H/L ratio and increased antibody production [4]. Similar enrichment resources also modified non-specific immune system responses following transport stress relative to non-enriched birds [5] and affected the weights of lymphoid organs [4,5], indicating the physiological impacts of varying developmental environments.…”

“…Comparisons between pullets reared in standard cages or cages with perches, strings, a dust bathing area and a nest box showed that these rearing enrichments improved immune responses under an imposed social stressor, including lowered H/L ratio and increased antibody production [4]. Similar enrichment resources also modified non-specific immune system responses following transport stress relative to non-enriched birds [5] and affected the weights of lymphoid organs [4,5], indicating the physiological impacts of varying developmental environments. With increasing recognition of the importance of layer rearing environments and consumer concerns for improved layer welfare, further evidence is needed for the potential benefits of rearing enrichments, particularly for free-range hens that experience large changes between rearing and layer systems.…”

“…Rearing environments for laying hens are important for the physical and behavioural development of pullets [1]. Providing resources in the rearing environment such as litter substrate or perches can ensure appropriate behavioural patterns are formed [2], physical strength is enhanced [3], or immune function is strengthened [4,5], thereby optimising hen welfare as adults. It is particularly important to consider how the rearing conditions may affect adaptability to a specific type of layer housing system, with recommended system matching between the rearing and adult phases [6].…”