Development of ileal cytokine and immunoglobulin expression levels in response to early feeding in broilers and layers.

Provision of feed in the immediate posthatch period may influence interaction between intestinal microbiota and immune system, and consequently immunological development of the chick. This study addressed ileal immune development in response to early feeding in 2 chicken breeds selected for different production traits: broilers and layers. Chicks of both breeds either received feed and water immediately posthatch or were subjected to a 72-h feed and water delay. Ileal cytokine and immunoglobulin mRNA expression levels were determined at different time points. Effects of early feeding were limited, but breeds differed strikingly regarding cytokine and immunoglobulin expression levels. Cytokine expression levels in broilers were low compared with layers and showed a transient drop in the second to third week of life. In contrast, broilers showed considerably higher expression levels of IgA, IgM, and IgY. These findings indicate that the 2 breeds use different immune strategies, at least on the ileal level.