Dietary inclusion of a liquid sugar- and organic acid-based feed modulates bioactive metabolites and antioxidant properties of mediterranean buffalo milk: in vitro evidence in endothelial cells

Consumer interest in functional foods has promoted research into nutritional strategies able to modulate animal-derived products. This study evaluated whether two isoenergetic and isoproteic feeding protocols, differing in carbohydrate sources, were associated with changes in the nutraceutical properties of buffalo milk. One hundred multiparous buffaloes were randomly assigned to two homogeneous groups balanced for days in milk, parity order and milk yield. Group C received the farm’s conventional ration containing sucrose and a higher amount of farm feed based on former food products containing biscuit meal, whereas Group T received a ration supplemented with a commercial liquid feed containing simple sugars, organic acids and nitrogenous compounds. For four months, individual and monthly bulk milk samples were analysed for yield, composition, l-carnitine, acetyl-l-carnitine, propionyl-l-carnitine, glycine betaine and antioxidant capacity. Milk yield, fat, protein, dry matter intake and body condition score did not differ between groups. Group T bulk milk showed higher levels of l-carnitine (26.2 vs 23.8 mg/L), acetyl-l-carnitine (27.1 vs 24.5 mg/L), propionyl- l-carnitine (11.3 vs 10.3 mg/L), glycine betaine (7.50 vs 7.10 mg/L) and antioxidant indices. Under high-glucose exposure, milk extracts from both groups improved endothelial cell viability, with a stronger response for Group T milk. Group T milk extract reduced cytotoxicity, cytokine release, lipid peroxidation, reactive oxygen species accumulation and senescence, while increasing sirtuin (SIRT) 1, SIRT3 and SIRT4 protein levels. Overall, the tested feeding protocol was associated with changes in buffalo milk bioactive profile and antioxidant capacity, supporting further in vivo validation.