Seasonal changes in diet affect fatty acid composition of Jersey milk in organic production system

The aim of this study was to determine effect of diet-based seasonal changes on fatty acid composition of Jersey milk in mountain region of Croatia. Bulk milk samples (200 mL) were collected during total-mixed ratio (TMR)-based, intermediate and pasture-based diet. Fatty acid composition of milk was determined by gas-chromatography. We found that pasture-based diet has positive effect on fatty acid composition of Jersey milk considering human nutrition. During pasture-based diet, Jersey cows produced milk with lower (P<0.05) saturated fatty acid and higher (P<0.05) polyunsaturated fatty acid content. Namely, regarding individual fatty acids, milk produced during pasture-based diet had lower (P<0.05) C16:0 and higher (P<0.05) C18:2n-6, C18:3n-6 and conjugated linoleic acid (CLA) content than milk produced during TMR and intermediate diet. Milk produced during pasture-based diet can be valuable source of healthbeneficial PUFA in diet.
Cilj ovog istraživanja bio je utvrditi utjecaj sezonskih promjena u sastavu obroka na profil masnih kiselina u mlijeku krava Jersey pasmine. Skupni uzorci mlijeka iz laktofriza (200 mL) prikupljeni su tijekom prehrane bazirane na potpuno izmiješanom obroku (TMR), prijelaznog razdoblja sa TMR-a na ispašu i samo ispaše. Profil masnih kiselina je određen plinskom kromatografijom. Utvrđeno je da hranidba bazirana na ispaši ima pozitivan utjecaj na profil masnih kiselina sa stanovišta ljudske prehrane. Tijekom hranidbe bazirane na ispaši u mlijeku Jersey krava utvrđen je manji (P<0,05) udio zasićenih masnih kiselina i veći (P<0,05) sadržaj polinezasićenih masnih kiselina. Naime, što se tiče udjela pojedinačnih masnih kiselina, mlijeko proizvedeno tijekom pašne sezone imalo je manji (P<0,05) udio C16:0 i veći (P<0,05) udio C18:2n-6, C18:3n-6 te CLA masnih kiselina. Mlijeko proizvedeno tijekom pašne sezone može biti vrijedan izvor višestruko nezasićenih masnih kiselina koji imaju poželjan nutritivni učinak.