Effect of early feeding on the transfer of maternal antibodies and development of immune competence in the broiler chicken

We investigated effects of early feeding on the development of maternal antibodies in yolk and plasma and the consequences on growth and immune responses in later life. Broiler chickens (Ross 308) were immediately fed after hatching or withheld from feed and water for 24, 48 or 72 h. Both fed and unfed chickens were sacrificed immediately after hatch or 24, 48 or 72 h after hatch and IgY contents of the residual yolk and plasma were analyzed. Another group of fed and held chickens was raised in floor housing till d 19 and were intra-tracheally challenged with a lipopolysaccharide (LPS) – Human Serum Albumen (HuSA) cocktail as a model for lung infection. Nitric oxide (NO) production and plasma antibody titers against LPS and HuSA were determined on d 0, 1, 3, 7, 14 and 21 postchallenge. Body weight showed a faster increase in the fed than in the held chickens, ending up in a body weight at d 40 of 2,269 and 1,994 g, respectively. Absorption of residual yolk was not affected by treatment, but results demonstrated that IgY in the yolk is not utilized as fast as the rest of the residual yolk, possibly due to dehydration in the held chickens or a kind of saturation in the IgY transport system in the fed chickens. No differences between treatments were found for NO production or LPS/HuSA antibody titers after the challenge. However, held chickens showed a significant decrease in growth following the LPS/HuSA challenge at d 19, whereas this drop in growth was less severe in the fed chickens. We concluded that early feeding in broiler chickens results in faster growth in later life, but also that fed chickens are better able to cope with an immunological challenge in later life, although this is not reflected in different antibody titers.