Occurrence of trans-C18:1 fatty acid isomers in goat milk: effect of two dietary regimens.
Trans-octadecenoic acid composition of goat milk fat was studied by using silver-ion thin layer chromatography combined with gas-liquid chromatography. This analytical procedure also was used to investigate the effect of diet on trans-C18:1 fatty acid content in goat milk. Thirty-two goats were used in a 2 x 2 factorial arrangement and treatments. Two groups of goats received alfalfa hay at either a high or a low level of forage and two other groups received Rumiluz (dehydrated alfalfa from France Luzerne, Châlon en Champagne, France) at either a high or a low level of forage. Trans-C18:1 isomer proportions (relative to total fatty acids) were, respectively, 2.02% for the Rumiluz low-level group and 1.75% for the Rumiluz high-level group versus 1.71% for the alfalfa low-level group and 1.21% for the alfalfa high-level group. Goats fed on Rumiluz thus produced relatively higher levels of trans-C18:1 fatty acids than animals fed alfalfa hay. The results also showed that production of trans-C18:1 fatty acids increased when the level of forage in the diet decreased. Moreover, goat milk trans-C18:1 composition appeared similar to the cow milk profile. Vaccenic acid, trans-11-C18:1, was the major component and represented about 36.2% of total trans-C18:1 isomers.
Ledoux
M
M
Agence Frangaise de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur la Qualité et l'Hygiène des Aliments, Maisons-Alfort, France. m.ledoux@paris.afssa.fr
Rouzeau
A
A
Bas
P
P
Sauvantt
D
D
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002855:Chromatography, Thin Layer / Q000379:methods / Q000662:veterinary; D004032:Diet / Q000662:veterinary*; D005229:Fatty Acids, Monounsaturated / Q000032:analysis / Q000302:isolation & purification*; D005260:Female; D006041:Goats; D000455:Medicago sativa; D008892:Milk / Q000737:chemistry*; D011897:Random Allocation; D013237:Stereoisomerism
D005229:Fatty Acids, Monounsaturated