GANGLIOSIDES IN BOVINE-MILK - CHANGES IN CONTENT AND DISTRIBUTION OF INDIVIDUAL GANGLIOSIDE LEVELS DURING LACTATION

Bovine milk undergoes changes in its ganglioside contents during the different stages of lactation. These contents are higher in colostrum (7.5 mg of lipid-bound NeuAc/kg) than in transitional (2.3 mg) or mature (1.4 mg) milk. The sialic acid content of milk follows a similar profile to that of gangliosides with the highest content during the first few days post partum followed by a gradual decrease towards the end of the period studied. When the individual distribution of gangliosides was examined throughout the course of lactation, several changes were also found. G(D3) is the major ganglioside (about 60-70%) found; its content decreases from the first to the fifth day, increasing towards the end of the period considered. G(M3), G(D3) and G(T3), sialyllactosyl-ceramide-containing gangliosides account for 80-90% of the total lipid-bound NeuAc content. The most striking change in the ganglioside pattern was the gradual increase in G3.