Plasma and milk fatty acid profiles in goats fed diets supplemented with oils from soybean, linseed or fish

Abstract

This study aimed to evaluate the effect of polyunsaturated fatty acids (FA) sources (soybean oil, linseed oil and fish oil) on apparent nutrient digestibility, milk composition, and the FA profile in the arterial blood plasma and the milk from dairy goats. Four multiparous Saanen goats were assigned to receive the experimental diets: control diet (no additional oil, with 425 g/kg DM of corn), or a diet substituting 20 g/kg DM of corn by either soybean oil (SO), linseed oil (LO) or fish oil (FO), which were arranged in a 4 × 4 Latin square design. The goats were housed in individual tie stalls, where they received diets containing 400 g/kg DM of corn silage and 600 g/kg DM of concentrate. The corn substitution by FAs sources did not affect apparent nutrient digestibility and milk composition (macro compounds). The oil sources changed the plasma and milk fatty acids profile differently. The plasma concentration of vaccenic and rumenic acids were strongly increased (P < 0.05) (about 500%) in diet containing FO, similarly the content of vaccenic and rumenic acids in the milk were also strongly increased (P < 0.05) (about 540 and 1380%, respectively) using FO, as well as the incorporation of EPA and DHA in the milk. The SO and LO treatments were able to change the profile of several FA in the arterial blood plasma; however, only linoleic and linolenic acids were increased (P < 0.05) in milk, respectively. Changes in plasma and milk FA were observed by adding FO, making the goats’ milk nutritionally healthier for the human diet because FO strongly increased the rumenic and vaccenic acids, EPA and DHA content. The SO and LO led to a few changes in milk FA profile.