Descripción del mecanismo bioquímico de la biohidrogenación en el rumen de ácidos grasos poliinsaturados: una revisión

Abstract

Hydrolysis of galactolipids, phospholipids, sulfolipids and triglycerides is the first step in ruminal lipid metabolism resulting in saturated, monounsaturated and polyunsaturated fatty acids. It has been reported recently that the mechanism of conjugated linoleic acid (C 18:2 cis-9, trans-11, CLA) production is associated with a prototropic displacement and the synthesis of its isomer C 18:2 trans-10, cis-12, involves oxidated flavin adenine dinucleotide (FAD). First, linoleic acid (C 18:2 cis-9, cis-12, LiA) is converted to CLA by the action of cis-9, trans-11 octadecanoate reductase, then CLA converts to trans-vaccenic acid (C 18:1 trans-11, TVA) with the final product being stearic acid. LiA is the precursor of both CLA and TVA and FAD is used as a cofactor in these processes. One of the conclusions of this review is that as the knowledge of the ruminal biohydrogenation process increases, opportunities for its application become available. The nutritional strategies to increase the concentration of bioactive fatty acids in both milk and meat are the more relevant.

Both Dietary Fatty Acids and Those Present in the Cecotrophs Contribute to the Distinctive Chemical Characteristics of New Zealand Rabbit Milk Fat

“…Bacteria in the cecum also modify FA and contribute to PUFA synthesis from the dietary intake of linoleic and linolenic acids (Amici et al, ; Bauman et al, ; Papadomichelakis et al, ). In ruminants, the microorganisms that metabolize FA include Ruminococcus , Fusocillus , and Anaerovibrio (Hobson and Stewart, ); Propionobacterium can produce CLA trans ‐10, cis ‐12 (Castillo et al, ), whereas Butyrivibrio can produce CLA cis ‐9, trans ‐11 (Wallace et al, ). Lactobacillus and Bifidobacterium have been identified in the cecum of rabbits (Comi and Cantoni, ) and they are also present in cecotrophs (Zeng et al, ).…”

Relationship between the Composition of Lipids in Forages and the Concentration of Conjugated Linoleic Acid in Cow’s Milk: A Review

“…After the lipolysis process, the released polyunsaturated and monounsaturated FAs are transformed through hydrogenation [23]. Biohydrogenation is a process that takes place in the rumen, consisting of the saturation (addition of hydrogen) of the double bonds present in FAs [22] and involves several biochemical steps, with speeds, intermediate, and characteristic bacterial species [24]. This activity is mainly associated with bacteria bound to feed particles; the free unsaturated FAs are absorbed on feed particle surfaces and hydrogenated [25], while the saturated FAs are not modified in the rumen.…”

“…The reduction of vaccenic acid seems to be the determining step in the biohydrogenation of linoleic and α-linolenic acids, and therefore, this intermediate could accumulate in the rumen, thus increasing its availability to be absorbed [24].…”

“…This process requires that acetate (from ruminal fermentation) be activated to acetyl-CoA by the acetyl-CoA synthetase enzyme and subsequently be carboxylated by the acetyl-CoA carboxylase enzyme to form malonyl-CoA, Figure 2 [22]. The reduction of vaccenic acid seems to be the determining step in the biohydrogenation of linoleic and α-linolenic acids, and therefore, this intermediate could accumulate in the rumen, thus increasing its availability to be absorbed [24].…”

An in vitro and in situ evaluation of a diet for cattle added with organic oils

“…LA and ALA are found in high proportions in the lipids of fodder and in some supplements, such as oils. Castillo et al (2013) point out that supplementing diets with LA-and ALA-rich soybean oil reduces short-chain fatty acids and increases long-chain unsaturated fatty acids (UFA) -especially TVA and CLA. For its part, fish oil contains eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid (C22:6 n-3, DHA); adding these acids to ruminant diets increases CLA concentration in milk and meat (Wąsowska et al, 2006).…”