Effects of age on sialic acid distribution. Sections from 1, 2, and 4 week old turkeys trachea (A-F) and 1, 2, and 4 week old duck large intestine (G-L) were stained with either DIG labeled MAA (α2,3 specific, A-C and G-I) or DIG labeled SNA (α2,6 specific, D-F and J-L). Little to no variation was seen in the staining of α2,3 SA in the turkey trachea or duck large intestine across the age range. However, both species show an increase in α2,6SA as the birds age. Arrows highlight positive reactions.