Identification of the Paneth cells in chicken small intestine

The Paneth cells are highly specialized cells in the epithelium of the small intestine of many vertebrate species. These cells reside at the base of crypts of the Lieberkühn and contain abundant secretory granules. Previous studies suggesting the existence of Paneth cells in the chicken (Gallus gallus) remained controversial. Here we seek to identify the Paneth cells in the chicken small intestine through morphological examination and specific gene expression. Histological staining and transmission electron microscope confirmed the presence of granulated secretory cells at the base of the crypts in the chicken small intestine. Western blotting experiment also manifested the expression of lysozyme protein, which is specifically secreted by the Paneth cells in the small intestine. Moreover, lysozyme c and lysozyme g mRNAs were expressed in the small intestine of chickens at different ages. Lysozyme c mRNA, in particular, was located at the base of the small intestinal crypts as displayed by in situ hybridization. Collectively, we provide evidences that the Paneth cells indeed exist in the small intestine of the chicken.