Developmental changes in mRNA expression in immune‐associated cells of intestinal tract of broiler chickens after hatch and by dietary modification

Abstract

ABSTRACTDevelopmental changes in the immune‐related cells of the gut during the first 2 weeks post hatching were determined in broiler chickens fed a corn–soybean meal (CS) based diet, a semi‐purified diet with high fat (HF) and a high carbohydrate (HC) diet. The expression of CD3 and interferon‐gamma (IFN‐γ) mRNA increased during 3–7 days of age. When the chicks were fed the CS diet, the expression of interleukin‐2 mRNA in the foregut did not increase with age. The expression of iNOS mRNA was lowered at 3 days of age in the fore‐ and mid gut but the expression was constant at the other days of age. TLR‐2 mRNA expression increased in three section of the gut during 3–7 days of age, while TLR‐4 expression increased during 0–3 days of age. Chicks fed the HC diet showed higher interleukin‐2 but lower IFN‐γ mRNA expression than birds fed the CS diet. Feeding the HF diet tended to decrease the expressions determined. These findings suggest that the functional maturation of the T cell does not always correlate with an increase in T cell numbers, maturation of innate immunity may occur earlier than that of T cells and possibly the dietary composition modifies the developmental pattern.