Short term evolution of nutritionally relevant milk fatty acids of goats fed a cereal-based concentrate enriched with linseed oil

Pilar Gómez-Cortés, Alfonso Cívico, Miguel Angel de la Fuente, Nieves Núñez Sánchez, Francisco Peña Blanco, Andrés L. Martínez Marín

Index: 10.1016/j.ifset.2018.03.020

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Abstract

Goat diet supplementation with linseed oil (LO) can be a fruitful technological strategy to enhance the nutritional value of milk fat. The objective of the present study was to determine the effect of LO in a basal diet rich in starch on goat milk fatty acid (FA) profile. The FA contents were monitored exhaustively during 24 h after LO supplementation or elimination by gas chromatography. Rumenic acid, the main conjugated linoleic acid isomer and α-linolenic acid, both related with bioactive properties, significantly rose in milk between 12 and 24 h after the inclusion of LO in the diet. On the contrary, medium-chain saturated FA decreased. Changes in other nutritionally relevant milk FA as well as short term effects caused by dietary LO suppression are discussed. Industrial relevance Fortification of livestock feeds with lipid supplements is a technological approach that has attracted growing attention in order to change milk fatty acid (FA) profile. Enrichment of ruminant diets with linseed oil (LO) increases omega-3 FA and conjugated linoleic acid as well as decreases saturated FA in milk fat, which improves the nutritional value of dairy products. The present study explores the timing of those changes in the first 24 h after LO inclusion or suppression in the diet. We observed that changes of goat milk fat composition occurred for the most part between 12 and 24 h of LO supplementation, while those changes disappeared between 6 and 12 h after LO suppression. These results would be relevant for producers and industrialists in order to establish appropriate milk collection periods which provide an improved FA profile due to LO supplementation.