t10,c12-CLA decreases adiposity in peripubertal mice without dose-related detrimental effects on mammary development, inflammation status, and metabolism.

The trans 10, cis 12-conjugated linoleic acid (10,12-CLA) isomer reduces adiposity in several animal models. In the mouse, however, this effect is associated with adipose tissue inflammation, hyperinsulinemia and hepatic lipid accumulation. Moreover, 10,12-CLA was recently shown to promote mammary ductal hyperplasia and ErbB2/Her2-driven mammary cancer in the mouse.

Hot topic: Enhancing omega-3 fatty acids in milk fat of dairy cows by using stearidonic acid-enriched soybean oil from genetically modified soybeans.

Very long chain n-3 fatty acids such as eicosapentaenoic acid (EPA; 20:5n-3) are important in human cardiac health and the prevention of chronic diseases, but food sources are limited. Stearidonic acid (SDA; 18:4n-3) is an n-3 fatty acid that humans are able to convert to EPA. In utilizing SDA-enhanced soybean oil (SBO) derived from genetically modified soybeans, our objectives were to examine the potential to increase the n-3 fatty acid content of milk fat and to determine the efficiency of SDA uptake from the digestive tract and transfer to milk fat.

Production responses of dairy cows to dietary supplementation with conjugated linoleic acid (CLA) during the transition period and early lactation.

Holstein cows (n = 30) entering second or greater lactation were fed fat supplements (90 g/d of fatty acids) consisting of Ca salts of either palm fatty acid distillate (control) or a mixture of palm fatty acid distillate and mixed isomers of conjugated linoleic acid (CLA, 30.4 g/ d) from 2 wk prepartum through 20 wk postpartum to determine whether CLA would inhibit milk fat synthesis during early lactation and, in turn, affect energy metabolism of dairy cows during the transition period and early lactation. Feeding CLA did not affect DMI or plasma concentrations of glucose, nonesterfied fatty acids, or beta-hydroxbutyrate during the prepartum period and did not affect postpartum DMI.

Effects of dietary supplementation of rumen-protected conjugated linoleic acid in dairy cows during established lactation.

Short-term studies (< 5 d) involving abomasal infusion of a mixture of CLA isomers or pure trans-10, cis-12 CLA have demonstrated that supplements of conjugated linoleic acids (CLA) reduce milk fat synthesis during established lactation in dairy cows. Our objective was to assess longer term effects of supplementation during established lactation using a dietary supplement of rumen-protected CLA. Thirty Holstein cows were blocked by parity and received a dietary fat supplement of either Ca-salts of palm oil fatty acids (control) or a mixture of Ca-salts of palm oil fatty acids plus Ca-salts of CLA (CLA treatment).