Apparent Recovery of Duodenal Odd- and Branched-Chain Fatty Acids in Milk of Dairy Cows

• Published in: Journal of dairy science 2007-04, Vol.90 (4), p.1775-1780
• Main Authors: Dewhurst, R.J., Moorby, J.M., Vlaeminck, B., Fievez, V.
• Format: Article
• Language: English
• Subjects: alpha-Linolenic Acid - metabolism; Animal productions; Animals; biohydrogenation; Biological and medical sciences; branched chain fatty acids; Cattle - physiology; cow feeding; dairy cow; dairy cows; Dairying; Diet - veterinary; digesta; duodenum; Duodenum - metabolism; fatty acids; Fatty Acids - metabolism; feed concentrates; Female; Food industries; Fundamental and applied biological sciences. Psychology; Gastrointestinal Contents - chemistry; grass silage; Holstein; Iso; Lactation - metabolism; linoleic acid; linolenic acid; Lolium; Milk - chemistry; Milk and cheese industries. Ice creams; milk composition; odd chain fatty acids; Proteins - metabolism; Terrestrial animal productions; Vertebrates
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2006-715

This study compared flows of odd- and branched-chain fatty acids (OBCFA) at the duodenum with corresponding yields in milk. Four mid-lactation Holstein-Friesian dairy cows were offered 4 dietary treatments, based on different ratios of ryegrass silage and concentrates (80:20, 65:35, 50:50, and 35:65 on a dry matter basis), in a 4×4 Latin square design experiment with 4-wk periods. Samples of milk and duodenal digesta were collected during the final week of each period and analyzed for fatty acids. Biohydrogenation of linoleic and α-linolenic acids (C18:2 and C18:3) was extensive for all treatments, with a tendency to be lower for C18:3 with increased concentrate feeding. The proportion of duodenal flows of these fatty acids that appeared in milk declined with increasing concentrate feeding. There was little change in the yield of OBCFA in milk in response to increasing level of concentrate inclusion and no significant relationship with the yield of microbial protein at the duodenum. The efficiency of transfer of iso C15:0 and anteiso C15:0 from the duodenum to milk was similar to that for C18:3, with a reduced proportion transferred into milk at higher flows. Yields of C15:0, C17:0, and iso C17:0 in milk were higher than duodenal flows, confirming synthesis in animal tissues.