Influence of conjugated linoleic acid (CLA) on the fatty acid profile of rabbit milk.

espanolEl efecto antilipogenico del acido linoleico conjugado (CLA) se ha evaluado en la vaca lechera,hipotetizandose que el CLA afecta la sintesis de novo, pero por no ser la principal ruta de sintesis de acidos grasos(AG), se desconoce a que nivel el CLA esta inhibiendo dicha sintesis. En las conejas la sintesis de novo es la principal ruta dela sintesis de AG pero se desconoce si el CLA cambia la composicion quimica de su leche o altera el perfil de sus AG, por lo que en este estudio se evaluo el efecto de la suplementacion oral del CLA sobre la composicion quimica y el perfil de los AG de la leche de conejas durante los primeros 12 dias de lactancia. Se emplearon 18 conejas Nueva Zelanda asignadas al azar entre el tratamiento 1) grupo control;y el tratamiento 2) suplementacion oral de 310 mg CLA/kg de peso metabolico. A partir del dia 5 y hasta el 12 postparto, se administro diariamente viaoral el CLA (Tonalin FFA, BASF®) y se obtuvieron muestras individuales de leche obtenidas por ordena manual. El perfil de los AG se determino por cromatografia de gases y cuantificados empleando estandares internos. El CLA suplementado no altero la composicion quimica de la leche de las conejas, pero modifico el perfil de los AG de lagrasa de leche reduciendo los AG de cadena larga mono-insaturados y poli-insaturados e incrementando la concentracion de C21:0y de los isomeros de C18:2, CLAcis9,trans11 y CLAtrans-10,cis-12. EnglishThe antilipogenic effect of conjugated linoleic acid (CLA) has been evaluated in the dairy cow, with thehypothesis that CLA affects de novo synthesis, but since that is not the main pathway for their fatty acid (FA)synthesis, it is not known at what level is CLA inhibiting such synthesis. In rabbits, de novo synthesis is the mainroute for FA synthesis, but is not known if in this species CLA changes milk composition or alters its FA profile,therefore the present study was conducted to evaluate the effect of oral supplementation of CLA on the chemicalcomposition and the FA profile of milk from rabbits during the first 12 days of lactation. Eighteen multiparous NewZealand rabbits were randomly assigned into treatment 1) control group, and treatment 2) supplemented with 310mg CLA/kg de metabolic body weight. From days 5 to 12 postpartum, CLA (Tonalin FFA, BASF®) was orallyadministered daily and individual milk samples were collected manually. FA profile was identified by gaschromatography and quantified by internal standards. CLA supplementation did not alter chemical composition ofthe rabbits’ milk, but modified the FA profile of the milk fat reducing mono-unsaturated and poly-unsaturated longchain FA and increasing the concentration of C21:0and of the C18:2isomerscis-9,trans-11 CLA andtrans-10,cis-12CLA.