Biohydrogenation of linoleic acid by rumen fungi compared with rumen bacteria

Nam, In Sik; Garnsworthy, P. C.

doi:10.1111/j.1365-2672.2007.03317.x

Cited by 47 publications

(38 citation statements)

References 32 publications

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“…Fungi (table 2) represent a small proportion, approximately 8%, of the biomass in the ruminal ecosystem (Jenkins et al 2008), but they do have a role in the digestion of food consumed by the ruminant (Nam and Garnsworthy 2007). Some fungi are microaerotolerants and are attached to feed particles through a system of rhizoids (Denman et al 2008).…”

Section: Ruminal Fungimentioning

confidence: 99%

Rumen microorganisms and fermentation

et al. 2014

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RESUMENEl rumen es un ecosistema complejo donde los nutrientes consumidos por los rumiantes son digeridos mediante un proceso de fermentación realizado por los microorganismos ruminales (bacterias, protozoos y hongos). Dichos microorganismos están en simbiosis, debido a su capacidad de adaptación e interacción, y mientras el rumiante proporciona el ambiente necesario para su establecimiento estos proporcionan energía al animal, la que proviene de los productos finales de la fermentación. Dentro del rumen, los microorganismos coexisten en un entorno reducido y a un pH cercano a la neutralidad. Estos microorganismos fermentan los sustratos presentes en la dieta del rumiante (azúcares, proteínas y lípidos). Sin embargo, el proceso de fermentación no es 100% eficaz, ya que durante la fermentación existen pérdidas de energía, principalmente en forma de gas metano (CH 4 ), el que representa un problema medioambiental, ya que es un gas de efecto invernadero. Por consiguiente, para mejorar la eficiencia de los sistemas de producción de rumiantes se han establecido estrategias nutricionales que tienen como objetivo manipular la fermentación ruminal mediante el uso de aditivos en la dieta, como monensina, sebo, tampones, compuestos de nitrógeno, probióticos, etc. Estos aditivos permiten cambiar el proceso de fermentación y mejorar la eficiencia animal, además disminuyen la pérdida de energía. El objetivo de este trabajo es revisar los procesos fermentativos que tienen lugar en el rumen y aplicar los fundamentos de estos en el desarrollo de nuevas estrategias nutricionales que pudieran ayudar a mejorar los procesos de digestión, de manera que se alcance una máxima producción.Palabras clave: aditivos, microorganismos ruminales, simbiosis. SUMMARYThe rumen consists of a complex ecosystem where nutrients consumed by ruminants are digested by fermentation process, which is executed by diverse microorganisms such as bacteria, protozoa, and fungi. A symbiotic relationship is found among different groups of microorganisms due to the diverse nature of these microbial species and their adaptability and interactions also coexist. The ruminant provides the necessary environment for the establishment of such microorganisms, while the microorganisms obtain energy from the host animal from microbial fermentation end products. Within the ruminal ecosystem, the microorganisms coexist in a reduced environment and pH remains close to neutral. Rumen microorganisms are involved in the fermentation of substrates contained in thedietof the animals (carbohydrates, proteins and lipids). However, the fermentation process is not 100% effective because there are energy losses mainly in the form of methane gas (CH 4 ), which is a problem for the environment since it is a greenhouse gas. In order to improve the efficiency of ruminant production systems, nutritional strategies that aim to manipulate ruminal fermentation using additives in the diet such as monensin, tallow, buffers, nitrogen compounds, probiotics, and others have been used. These additi...

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Section: Ruminal Fungimentioning

confidence: 99%

Rumen microorganisms and fermentation

et al. 2014

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“…Characterizing the formation of intermediates and production of end products arising from the biohydrogenation of lipids in the rumen is central to attempts to enhance the nutritional attributes of ruminant milk fat. Biohydrogenation has been studied for many years, most recently in attempts to identify species that form isomers of conjugated linoleic acid (CLA) as transient intermediates during the metabolism of linoleic acid (cis-9,cis-12-18 : 2) to 18 : 0 (Kim et al, 2002;Paillard et al, 2007;Wallace et al, 2006;Nam & Garnsworthy, 2007) and the mechanisms responsible for CLA synthesis . Isomers of CLA also serve as a substrate for reduction to 18 : 1 intermediates and 18 : 0 (Kepler et al, 1966;Harfoot & Hazlewood, 1997).…”

Section: Introductionmentioning

confidence: 99%

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

2010

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Cultures of ruminal bacteria known to metabolize unsaturated fatty acids were grown in medium containing 50 mg ml "1 of geometric and positional isomers of conjugated linoleic acid (CLA) or 18 : 1 fatty acids and 37.4 % deuterium oxide to investigate the mechanisms responsible for fatty acid metabolism. Butyrivibrio fibrisolvens JW11 converted cis-9,trans-11-18 : 2 and trans-9,trans-11-18 : 2 to trans-11-18 : 1 as the main product, labelled at C-9, and metabolized trans-10,cis-12-18 : 2 to trans-10-18 : 1, labelled at C-13, and smaller amounts of trans-12-18 : 1 and cis-12-18 : 1. Butyrivibrio proteoclasticus P-18 did not grow in the presence of cis-9,trans-11-18 : 2 or trans-10,cis-12-18 : 2, but grew in medium containing trans-9,trans-11-18 : 2, forming 18 : 0. Propionibacterium acnes, a ruminal species that isomerizes linoleic acid to trans-10,cis-12-18 : 2, did not metabolize CLA isomers further. B. fibrisolvens metabolized small amounts of trans-10-18 : 1, trans-11-18 : 1 and cis-9-18 : 1, but the products formed were not detected. B. proteoclasticus, on the other hand, carried out substantial conversion of 18 : 1 substrates to 18 : 0. P. acnes hydrated cis-9-18 : 1 and trans-11-18 : 1 to 10-OH-18 : 0, which was further oxidized to yield 10-O-18 : 0. The deuterium enrichment in the intermediates formed during incubations with 9,11 geometric isomers of CLA was about half that of the products from trans-10,cis-12 CLA and 18 : 1 isomers, suggesting that the reduction of 9,11 geometric isomers CLA by ruminal bacteria occurs via different mechanisms compared with the metabolism of other unsaturated fatty acids.

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“…Moreover, an in vitro study demonstrated that rumen fungi have the capacity to biohydrogenate LA, with Orpinomyces fungus being the most active. RBH is slower in fungi than in bacteria and has trans-11-18:1 as the end product (Nam and Garnsworthy, 2007).…”

Section: Microorganisms Involved In Rumen Biohydrogenationmentioning

confidence: 99%

A Review of the Metabolic Origins of Milk Fatty Acids

et al. 2013

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Milk fat and its fatty acid profile are important determinants of the technological, sensorial, and nutritional properties of milk and dairy products. The two major processes contributing to the presence of fatty acids in ruminant milk are the mammary lipogenesis and the lipid metabolism in the rumen. Among fatty acids, 4:0 to 12:0, almost all 14:0 and about a half of 16:0 in milk fat derive from de novo synthesis within the mammary gland. De novo synthesis utilizes as precursors acetate and butyrate produced through carbohydrates ruminal fermentation and involves acetyl-CoA carboxylase and fatty acid synthetase as key enzymes. The rest of 16:0 and all of the longchain fatty acids derive from mammary uptake of circulating lipoproteins and nonesterified fatty acids that originate from digestive absorption of lipids and body fat mobilization. Further, long-chain fatty acids as well as medium-chain fatty acids entering the mammary gland can be desaturated via Δ-9 desaturase, an enzyme that acts by adding a cis-9-double bond on the fatty acid chain. Moreover, ruminal biohydrogenation of dietary unsaturated fatty acids results in the formation of numerous fatty acids available for incorporation into milk fat. Ruminal biohydrogenation is performed by rumen microbial population as a means of protection against the toxic effects of polyunsaturated fatty acids. Within the rumen microorganisms, bacteria are principally responsible for ruminal biohydrogenation when compared to protozoa and anaerobic fungi.

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Biohydrogenation of linoleic acid by rumen fungi compared with rumen bacteria

Cited by 47 publications

References 32 publications

Rumen microorganisms and fermentation

Rumen microorganisms and fermentation

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

A Review of the Metabolic Origins of Milk Fatty Acids

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