Dietary Fatty Acid Sources Affect Conjugated Linoleic Acid Concentrations in Milk from Lactating Dairy Cows

Abstract

Conjugated linoleic acid (CLA), a naturally occurring anticarcinogen found in dairy products, is an intermediary product of ruminal biohydrogenation of polyunsaturated fatty acids. Our objective was to determine the effect of different dietary oils, which vary in fatty acid composition, on CLA concentrations in milk from lactating dairy cows. Twelve Holstein cows were randomly assigned to a 3 x 3 Latin square design. Dietary treatments were the addition (53 g/kg dietary dry matter) of peanut oil (high oleic acid), sunflower oil (high linoleic acid) and linseed oil (high linolenic acid). Each treatment period was 2 wk, and milk samples were collected on the last 4 d of each period. Milk yield (34.2 +/- 1.3 kg/d) and milk fat (2.25 +/- 0.06%) were not different among treatments. Milk protein during the sunflower oil treatment (mean, 3.44% protein) was significantly higher (P < 0.01) than during the other treatments. Milk fat concentration of CLA during the sunflower oil treatment was significantly different from other treatments (P < 0.001) and approximately 500% greater than typically observed when cows consume traditional diets. CLA concentrations (mg/g of milk fat) were 13.3, 24.4 and 16.7 during peanut oil, sunflower oil and linseed oil treatment, respectively. CLA concentration in milk fat can be enhanced by the addition of polyunsaturated fatty acids to the diet, especially oils high in linoleic acid.

Influence of an increase in diet structure on milk conjugated linoleic acid content of cows fed extruded linseed

“…The SV of the 'linseed 1 vitamin E' diet in Pottier et al (2006) was calculated precisely, the NDF content of the maize silage being available (403 g/kg of DM, unpublished data), and amounted to 1.01/kg of DM, which was very close to the minimum required SV of 1/kg of DM. Here again, we were not able to precisely estimate the SV of the diets in the experiments of Dhiman et al (2000) and Kelly et al (1998). However, we can reasonably assume that the lower dietary NDF contents in the experiments of Dhiman et al (2000) and Kelly et al (1998), as compared to those in the present experiment and in that of Bell et al (2006) (28.30% and 29.10% v. 42.86% and 45.30% of DM, respectively) contributed to lower the SV.…”

“…Here again, we were not able to precisely estimate the SV of the diets in the experiments of Dhiman et al (2000) and Kelly et al (1998). However, we can reasonably assume that the lower dietary NDF contents in the experiments of Dhiman et al (2000) and Kelly et al (1998), as compared to those in the present experiment and in that of Bell et al (2006) (28.30% and 29.10% v. 42.86% and 45.30% of DM, respectively) contributed to lower the SV. Loor et al (2005) reported a decrease in milk c9,t11-CLA concentration with a 65 : 35 F : C diet compared to a 35 : 65 F : C diet.…”

“…However, we were not able precisely to estimate the SV of the 'H-L' diet in the experiment of Roy et al (2006) because the grass hay NDF content was not available. Much lower concentrations of CLA were reported in the experiments of Pottier et al (2006) (values taken on day 21 of each period), Dhiman et al (2000) (mean values taken from weeks 2 to 5) and Kelly et al (1998) (mean values taken from day 11 to day 14). These concentrations amounted, respectively, to 1.14% (c9,t11-CLA), 1.63% (CLA) and 1.67% (CLA) of FA and were associated with MFD, except for the 'linseed 1 vitamin E' diet in Pottier et al (2006) where vitamin E was added.…”

“…**trans-UFA 5 t9-16:11t9-18:11t10-18:11t11-18:11c9,t11-CLA. the CLA content in milk fat (Kelly et al, 1998;Dhiman et al, 2000;Loor et al, 2005). However, we should bear in mind that FA values were overestimated since they were expressed as a percentage of FA reported and not as a percentage of total FA.…”

The influence of Iraqi mothers' socioeconomic status on their milk-lipid content

“…One of the important unsaturated FAs is CLA, C 18:2 ct, which is considered to be anticarcinogenic, antiatherosclerotic and a potent antioxidant component (Kramer et al, 1997;Park et al, 1997;Jensen et al, 1998;Kelly et al, 1998). The presence of CLA in breast-milk reflects the mother's intakes of hydrogenated fat and ruminant products.…”