Carnitine Precursors and Short-Chain Acylcarnitines in Water Buffalo Milk

Ruminants' milk contains delta-valerobetaine originating from rumen through the transformation of dietary N-epsilon-trimethyllysine. Among ruminant's milk, the occurrence of delta-valerobetaine, along with carnitine precursors and metabolites, has not been investigated in buffalo milk, the second most worldwide consumed milk, well-known for its nutritional value. HPLCESI-MS/MS analyses of bulk milk revealed that the Italian Mediterranean buffalo milk contains delta-valerobetaine at levels higher than those in bovine milk. Importantly, we detected also gamma-butyrobetaine, the L-carnitine precursor, never described so far in any milk. Of interest, buffalo milk shows higher levels of acetylcarnitine, propionylcarnitine, butyrylcarnitine, isobutyrylcarnitine, and 3-methylbutyrylcarnitine (isovalerylcarnitine) than cow milk. Moreover, buffalo milk shows isobutyrylcarnitine and butyrylcarnitine at a 1-to-1 molar ratio, while in cow's milk this ratio is 5 to 1. Results indicate a peculiar short-chain acylcarnitine profile characterizing buffalo milk, widening the current knowledge about its composition and nutritional value.