Effects of feeding increasing dietary levels of high oleic or regular sunflower or linseed oil on fatty acid profile of goat milk

Abstract

In this work, the effects of increasing amounts of 3 plant oils in diets on the fatty acid (FA) profile of goat milk were studied. The study consisted of 3 experiments, one per oil tested (linseed oil, LO; high oleic sunflower oil, HOSFO; and regular sunflower oil, RSFO). The 3 experiments were conducted successively on 12 Malagueña goats, which were assigned at random to 1 of 4 treatments: 0, 30, 48, and 66 (H) g of added oil/d. A basal diet made of alfalfa hay and pelleted concentrate (33:67) was used in all of the experiments. For each animal, milk samples collected after 15 d on treatments were analyzed for fat, protein, lactose, and FA composition, whereas individual milk yield was measured the last 3 d of each experiment. Oil supplementation affected neither dry matter intake nor milk production traits. Increasing the oil supplementation decreased the content of saturated FA (especially 16:0) in milk fat and increased mono- and polyunsaturated FA in a linear manner. Vaccenic acid content linearly increased with the oil supplementation by 370, 217, and 634% to 5.32, 2.66, and 5.09 g/100 g of total FA methyl esters with the H diet in LO, HOSFO, and RSFO experiments, respectively. Rumenic acid content linearly increased with LO and RSFO supplementation by 298 and 354% from 0.53 and 0.41 g/100 g of total FA methyl esters with the 0 g of added oil/d diet. The content of trans-10-18:1 was not affected by LO supplementation but showed an increasing linear trend with HOSFO supplementation and linearly increased with RSFO supplementation. The ratio of n-6 to n-3 polyunsaturated FA in milk fat was decreased by about 70% with the H diet in the LO experiment and it was increased by 54 and 82% with the H diet in the HOSFO and RSFO experiments. In conclusion, LO supplementation in this work seemed to be the most favorable alternative compared with HOSFO or RSFO supplementation.