Effect of supplementing palmitic acid and altering the dietary ratio of n-6:n-3 fatty acids in low-fibre diets on production responses of dairy cows

Abstract

Supplementing palmitic acid (C16:0) in combination with modifying the dietary n-6/n-3 fatty acids (FA) ratio may benefit energy metabolism and milk responses of dairy cows. Twelve Holstein cows (70±11 days in milk) were used in a replicated 4×4 Latin square, and allocated to 4 low-fibre diets (18.5% forage neutral detergent fibre) supplemented with no FA (CON), or 2.4% C16:0-enriched supplement (PAL), 2.4% mixture (2:1) of C16:0 and n-6 FA (PW6), and mixture (2:1) of C16:0 and n-3 FA (PW3). The dietary ratio of n-6/n-3 was increased with PW6 (10:1) and decreased with PW3 (2.8:1), whereas PAL alone made no change in the ratio (~7:1). Compared with CON, all FA-supplemented treatments increased milk yield. However, feed and energy intake was higher in PAL than PW3 or PW6, resulting in greater feed efficiency for PW3 and PW6 than PAL. Dietary FA supplements decreased milk protein concentration but tended to increase protein yield. Compared with CON and FA mixtures, PAL increased milk fat content and tended to increase milk saturated FA and atherosclerotic index. The concentration of milk n-3 FA was similar between CON and PW3. Feeding PAL increased milk energy output and decreased energy partitioning toward body reserves (-4.2%), while this measure was positive for other treatments. Blood triglyceride and NEFA concentrations, but not β-hydroxybutyrate, were increased by FA-supplemented treatments. Feeding C16:0 combined with either n-6 or n-3 FA, enhanced feed efficiency, alleviated the negative impacts on body energy reserves, but lowering the dietary n-6/n-3 ratio improved FA profile of milk.

Altering Methane Emission, Fatty Acid Composition, and Microbial Profile during In Vitro Ruminant Fermentation by Manipulating Dietary Fatty Acid Ratios

“…Nevertheless, the study results concur with previous reports, in which high-forage diets supplemented with oil enriched with n-6 PUFAs (soybean oil) interfered with ruminal fermentation in dairy cows [54]; on the other hand, oil enriched with n-3 PUFAs (flaxseed oil) [53] and saturated FAs (palm oil) [52] had no effects on ruminal pH and total VFAs, respectively. Notably, the acetate to propionate ratio was not affected by any of the dietary treatments, which concurred with another study demonstrating that the FA type did not affect the acetate to propionate ratio in the rumen [55].…”

The Blood Immune Cell Count, Immunoglobulin, Inflammatory Factor, and Milk Trace Element in Transition Cows and Calves Were Altered by Increasing the Dietary n-3 or n-6 Polyunsaturated Fatty Acid Levels

“…Many types of evidence showed that the immune system was impared during the transition period, including decreased mitogen-induced proliferation of lymphocytes, decreased antibody response, and decreased capacity of neutrophils to kill pathogens ( 5 ). One strategy to improve the metabolic status of transition cows is supplementing fatty acids (FAs), which can increase dietary energy density ( 6 , 7 ) and modulate the immune cell function and inflammatory response ( 8 ). Fatty acids can modify the immune response in several pathways, which include the inhibition of arachidonic acid metabolism, induction of anti-inflammatory mediators, modification of intracellular lipids, and activation of nuclear receptors ( 9 , 10 ).…”

The function of omega-3 polyunsaturated fatty acids in response to cadmium exposure

“…Their metabolisms are based on the same enzymes, which makes them competitive. There is evidence that higher concentration of n-6 PUFAs diet could result in lower conversion rate of ALA, and conversely, high concentrations of ALA could also reduce conversion of n-6 PUFAs (17)(18)(19). In light of this, numerous studies have revealed that the ratio of n-3/n-6 is closely related to body health, which again highlights the importance of the ratio of healthy dietary intake.…”