Nucleotides in canine colostrum and milk at different stages of lactation

The aim of this study was to investigate the presence of nucleotides in canine colostrum and milk during lactation. Colostrum and milk samples of 10 healthy bitches were collected manually from mammary glands and analysed for total milk solids, crude protein and adenosine 5’-monophosphate (AMP), cytidine 5’-monophosphate (CMP), guanosine 5’-monophosphate (GMP) and uridine 5’-monophosphate (UMP). We found that the total nucleotide content significantly (p < 0.05) increased during lactation, with UMP and CMP being the most abundant, while the AMP content was the lowest. The trend for CMP and UMP was opposite to that of other species, while AMP and GMP concentrations in bitch colostrum and milk were lower than those in other species. This is the first report on the presence of nucleotides in canine milk, and their occurrence could indicate a species-specific nucleotide metabolism or different secretory mechanisms.