Starch plus sunflower oil addition to the diet of dry dairy cows results in a trans-11 to trans-10 shift of biohydrogenation

Abstract

Trans fatty acids (FA), exhibit different biological properties. Among them, cis-9,trans-11 conjugated linoleic acid has some interesting putative health properties, whereas trans-10,cis-12 conjugated linoleic acid has negative effects on cow milk fat production and would negatively affect human health. In high-yielding dairy cows, a shift from trans-11 to 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. To study this shift, 4 rumen-fistulated nonlactating Holstein cows were assigned to a 4×4 Latin square design with 4 different diets during 4 periods. Cows received 12 kg of dry matter per day of 4 diets based on corn silage during 4 successive periods: a control diet (22% starch, <3% crude fat on DM basis), a high-starch diet supplemented with wheat plus barley (35% starch, <3% crude fat), a sunflower oil diet supplemented with 5% of sunflower oil (20% starch, 7.6% crude fat), and a high-starch plus sunflower oil diet (33% starch, 7.3% crude fat). Five hours after feeding, proportions of trans-11 BH isomers greatly increased in the rumen content with the addition of sunflower oil, without change in ruminal pH compared with the control diet. Addition of starch to the control diet had no effect on BH pathways but decreased ruminal pH. The addition of a large amount of starch in association with sunflower oil increased trans-10 FA at the expense of trans-11 FA in the rumen content, revealing a trans-11 to trans-10 shift. Interestingly, with this latter diet, ruminal pH did not change compared with a single addition of starch. This trans-11 to trans-10 shift occurred progressively, after a decrease in the proportion of trans-11 FA in the rumen, suggesting that this shift could result from a dysbiosis in the rumen in favor of trans-10-producing bacteria at the expense of those producing trans-11 or a modification of bacterial activities.

Ruminal fermentation and degradation, kinetic flow of the digesta and milk fatty acid composition of cows fed chopped elephantgrass supplemented with soybean oil

“…These results, supported by the linear reductions observed in the molar ratio of acetate (P=0.0741; Table 2) and in the purine derivatives excretion (P=0.0127; Table 4), are indicative that the inclusion of SO in the diet promoted dysbiosis in the bacterial community of the rumen (ZENED et al, 2013). There have probably been more significant reductions in the population and activity of cellulolytic strains, which are more vulnerable to the bacteriostatic effects of polyunsaturated-FAs (VLAEMINCK et al, 2006), which negatively affect the ruminal degradation of the fibrous fraction of the diet.…”

“…The main route of ruminal biohydrogenation of linoleic acid is carried out by bacteria of the species Butyrivibrio fibrisolvens with formation of rumenic and vaccenic acids . However, the high input of linoleic acid in the rumen can trigger the need to adapt the ruminal microbiota for the execution of biohydrogenation by an alternative route (ZENED et al, 2013). In this sense, McKain et al (2010) demonstrated in vitro that the bacterium Propionibacterium acnes does not metabolize geometric isomers of CLA but is specialized in isomerizing linoleic acid to trans-10, cis-12 CLA.…”

Fat and starch as additive risk factors for milk fat depression in dairy diets containing corn dried distillers grains with solubles

“…Based on rumen pH and ammonia concentration, no evidence of altered rumen environment among treatments was seen, therefore suggesting that altered biohydrogenation leading to MFD may develop without evident modifications in rumen conditions. Such a scenario has been reported by Zened et al (2013), who fed dry cows a combination of high sunflower oil and high starch (7.3% crude fat and 33% starch, dietary DM). They did not observe a significant interaction of these factors on rumen pH but reported a significant increased formation of trans-10 isomers in rumen fluid.…”

Effects of sucrose and sunflower oil addition to diet of Saanen dairy goats on performance and milk fatty acid profile

“…Feeding different kinds of unsaturated fat sources to dairy goats increase the percentages of milk C18:0 and C18:1, at the expense of mainly C8 to C14 (Chilliard et al, 2003). Zened et al (2013) observed when sunflower oil, rich in cis-9, cis-12 C18:2, was added to the diet, the ruminal pH did not change and the proportion of trans-11 biohydrogenation intermediates in the rumen content greatly increased, whereas the association of increasing starch level and adding cis-9, cis-12 C18:2 to the diet of cows did not change ruminal pH compared with the single addition of starch, but resulted in trans-10 FA increasing at the expense of trans-11 FA. However, accumulating evidence indicates that sugar significantly decreased the proportions of both polyunsaturated (Mullins and Bradford, 2010) and trans-C18:1 FA in milk fat and tended to increase milk fat yield .…”