Effects of abomasal infusions of fatty acids and 1-carbon donors on apparent fatty acid digestibility and incorporation into milk fat in cows

Our primary objective was to determine the effects of abomasal infusion 16-carbon (16C) and 22-carbon (22C) fatty acids (FA) on apparent FA digestibility, plasma concentrations, their incorporation into milk fat in cows. secondary study 1-carbon donors choline l-serine these variables. Five rumen-cannulated Holstein cows (214 ± 4.9 d milk; 3.2 1.1 parity) were enrolled a 5 × Latin square experiment with experimental periods lasting 6 d. Abomasal infusates consisted (1) palmitic acid (PA; 98% 16:0 total fat), (2) PA + chloride (PA+CC; 50 g/d chloride), (3) (PA+S; 170 l-serine), (4) behenic (BA; 92% 22:0 (5) docosahexaenoic algal oil (DHA; 47.5% DHA fat). Emulsions formulated provide 301 balanced minimum 40 19 glycerol, respectively, match content found infused oil. Apparent digestibility highest DHA, intermediate PA, lowest BA. Digestibility 16C BA PA. The 22C relative (99 vs. 58%), whereas had no effect digestibility. Plasma concentrations greatest treatment, ~3-fold greater DHA-treated all other treatments. Milk (e.g., 37 27% DHA), yield higher (i.e., 454 235 g/d). Similarly, ~10-fold treatments, treatment resulted 22:6 treatments (41- 38-fold higher, respectively). Consequently, >16C preformed) from De novo did not differ between PA+CC, PA+S (~16% fat) but (19 21%, We conclude that carbon chain length degree saturation affected availability for absorption as well fat. modify variables infusing alone.