Effects of oil and natural or synthetic vitamin E on ruminal and milk fatty acid profiles in cows receiving a high-starch diet

• Published in: Journal of dairy science 2012-10, Vol.95 (10), p.5916-5926
• Main Authors: Zened, A., Troegeler-Meynadier, A., Najar, T., Enjalbert, F.
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; Cattle; Diet - methods; Diet - veterinary; Dietary Carbohydrates - metabolism; Dietary Carbohydrates - pharmacology; Dietary Supplements; Fat industries; Fatty Acids - analysis; Female; Food and Nutrition; Food industries; Fundamental and applied biological sciences. Psychology; Gastrointestinal Contents - chemistry; Life Sciences; Milk - chemistry; milk fatty acid; Plant Oils - pharmacology; Rumen - chemistry; rumen biohydrogenation; Silage; Starch - metabolism; Starch - pharmacology; Sunflower Oil; Terrestrial animal productions; trans-10 shift; Triticum; Vertebrates; vitamin E; Vitamin E - pharmacology; Vitamins - pharmacology; Zea mays
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2012-5326

Among trans fatty acids, trans-10,cis-12 CLA has negative effects on cow milk fat production and can affect human health. In high-yielding dairy cows, a shift from the trans-11 to the trans-10 pathway of biohydrogenation (BH) can occur in the rumen of cows receiving high-concentrate diets, especially when the diet is supplemented with unsaturated fat sources. In some but not all experiments, vitamin E has been shown to control this shift. To ascertain the effects of vitamin E on this shift of BH pathway, 2 studies were conducted. The first study explored in vitro the effects of addition of natural (RRR-α-tocopherol acetate) and synthetic (dl-α-tocopherol acetate) vitamin E. Compared with control and synthetic vitamin E, the natural form resulted in a greater trans-10/trans-11 ratio; however, the effect was very low, suggesting that vitamin E was neither a limiting factor for rumen BH nor a modulator of the BH pathway. An in vivo study investigated the effect of natural vitamin E (RRR-α-tocopherol) on this shift and subsequent milk fat depression. Six rumen-fistulated lactating Holstein cows were assigned to a 2×2 crossover design. Cows received 20-kg DM of a control diet based on corn silage with 22% of wheat, and after 2 wk of adaptation, the diet was supplemented with 600 g of sunflower oil for 2more weeks. During the last week of this 4-wk experimental period, cows were divided into 2 groups: an unsupplemented control group and a group receiving 11 g of RRR-α-tocopherol acetate per day. A trans-10 shift of ruminal BH associated with milk fat depression due to oil supplementation of a high-wheat diet was observed, but vitamin E supplementation of dairy cows did not result in a reversal toward a trans-11 BH pathway, and did not restore milk fat content.