Fig. 4From: Age-related changes in the shell gland and duodenum in relation to shell quality and bone strength in commercial laying hen hybridsLocalisation of active carbonic anhydrase (CA) in shell gland of Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) hens at different ages during a production period. Active CA is shown as black staining. Shell gland mucosal fold of 70-week-old LSL hens shows no detectable staining for CA in surface epithelium (S). Intense membrane-bound staining of endothelial cells (arrow) in capillaries and weak membrane-bound staining of tubular glands (G and arrowhead) can be seen. Bar = 20 µm. Weak azure blue counterstainBack to article page