Influence of different dietary forages on the fatty acid composition of rumen digesta as well as ruminant meat and milk

Lourenço, Marta Ribeiro Alves; Ranst, Gijs Van; Vlaeminck, Bruno; Smet, Stefaan De; Fievez, Veerle

doi:10.1016/j.anifeedsci.2007.05.043

Cited by 118 publications

(81 citation statements)

References 66 publications

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“…Second, lipids and proteins are in close proximity embedded in a cell/organelle membrane (e.g. in the chloroplast) when quinones polymerize in and between membrane proteins, they could form a protecting envelope, protecting lipids from degradation (Lee et al, 2008b;Lourenço et al, 2008). Third, some polar lipids have potential nucleophilic binding sites, thus direct binding of quinones to lipids protects the lipids from enzymatic degradation.…”

Section: Ppo Activation In Red Clovermentioning

confidence: 99%

Red clover polyphenol oxidase and lipid metabolism

Ranst

Lee

Fievez

2011

Animal

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Increasing the polyunsaturated fatty acid (PUFA) composition of milk is acknowledged to be of benefit to consumer health. Despite the high PUFA content of forages, milk fat contains only about 3% of PUFA and only about 0.5% of n-3 fatty acids. This is mainly due to intensive lipid metabolism in the rumen (lipolysis and biohydrogenation) and during conservation (lipolysis and oxidation) such as drying (hay) and ensiling (silage). In red clover, polyphenol oxidase (PPO) has been suggested to protect lipids against degradation, both in the silage as well as in the rumen, leading to a higher output of PUFA in ruminant products (meat and milk). PPO mediates the oxidation of phenols and diphenols to quinones, which will readily react with nucleophilic binding sites. Such binding sites can be found on proteins, resulting in the formation of protein-bound phenols. This review summarizes the different methods that have been used to assess PPO activity in red clover, and an overview on the current understanding of PPO activity and activation in red clover. Knowledge on these aspects is of major importance to fully harness PPO's lipid-protecting role. Furthermore, we review the studies that evidence PPO-mediated lipid protection and discuss its possible importance in lab-scale silages and further in an in vitro rumen system. It is demonstrated that high (induction of) PPO activity can lead to lower lipolysis in the silage and lower biohydrogenation in the rumen. There are three hypotheses on its working mechanism: (i) protein-bound phenols could directly bind to enzymes (e.g. lipases) as such inhibiting them; (ii) binding of quinones in and between proteins embedded in a lipid membrane (e.g. in the chloroplast) could lead to encapsulation of the lipids; (iii) direct binding of quinones to nucleophilic sites in polar lipids also could lead to protection. There is no exclusive evidence on which mechanism is most important, although there are strong indications that only lipid encapsulation in protein-phenol complexes would lead to an effective protection of lipids against ruminal biohydrogenation. From several studies it has also become apparent that the degree of PPO activation could influence the mode and degree of protection. In conclusion, this review demonstrates that protein-bound phenols and encapsulation in protein-phenol complexes, induced by PPO-mediated diphenol oxidation, could be of interest when aiming to protect lipids against pre-ruminal and ruminal degradation.Keywords: red clover, polyphenol oxidase, lipid metabolism, rumen, silage ImplicationsPolyphenol oxidase (PPO) is an enzyme that has been found to be active in red clover. There is a whole range of recent studies exploring possibilities of using this enzyme to protect membrane lipids against degradation in the forage during storage and in the rumen of ruminants. Protection of lipids against degradation is of importance as it could help to improve the fatty acid profile of ruminant products, with respect to consumer health. This review aims to summarize...

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Section: Ppo Activation In Red Clovermentioning

confidence: 99%

Red clover polyphenol oxidase and lipid metabolism

Ranst

Lee

Fievez

2011

Animal

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“…Although, the explanation for this contradiction is not unambiguously clear, it might be linked to the presence in silages and to a lower extent in fresh or wiled forages of bound phenols. Indeed, protein-bound phenols have been suggested to protect lipids by encapsulation of lipids in protein-phenol complexes (Lee et al, 2008;Lourenço et al, 2008), which would be similar to the protection of lipids against biohydrogenation using formaldehyde (Gulati et al, 2005). Nevertheless, differences in protein-bound phenols after wilting of ND and FT silages did not result in differences in biohydrogenation in in vitro incubations.…”

Section: Silagesmentioning

confidence: 99%

“…Therefore, a lower lipolysis in the silage, induced by limiting silage duration and by increasing proteinbound phenols, could lead to lower biohydrogenation of PUFA in the rumen. It can be hypothesized that the lower in vitro biohydrogenation of red clover compared with grass PUFA (Loor et al, 2003) would be the result of a direct protection of the red clover lipids, for example, by enscapsulation of lipids in protein-phenol complexes (Lee et al, 2008;Lourenço et al, 2008) and not (only) due to plant lipase inhibition.…”

Section: Introductionmentioning

confidence: 99%

Influence of damaging and wilting red clover on lipid metabolism during ensiling and in vitro rumen incubation

Ranst¹,

Fievez

Vandewalle³

et al. 2010

Animal

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This paper describes the relationship between protein-bound phenols in red clover, induced by different degrees of damaging before wilting and varying wilting duration, and in silo lipid metabolism. The ultimate effect of these changes on rumen biohydrogenation is the second focus of this paper. For this experiment, red clover, damaged to different degrees (not damaged (ND), crushing or frozen/thawing (FT)) before wilting (4 or 24 h) was ensiled. Different degrees of damaging and wilting duration lead to differences in polyphenol oxidase (PPO) activity, measured as increase in protein-bound phenols. Treatment effects on fatty acid (FA) content and composition, lipid fractions (free FAs, membrane lipids (ML) and neutral fraction) and lipolysis were further studied in the silage. In FT, red clover lipolysis was markedly lower in the first days after ensiling, but this largely disappeared after 60 days of ensiling, regardless of wilting duration. This suggests an inhibition of plant lipases in FT silages. After 60 days of ensiling no differences in lipid fractions could be found between any of the treatments and differences in lipolysis were caused by reduced FA proportions in ML of wilted FT red clover. Fresh, wilted (24 h) after damaging (ND or FT) and ensiled (4 or 60 days; wilted 24 h; ND or FT) red clover were also incubated in rumen fluid to study the biohydrogenation of C18:3n-3 and C18:2n-6 in vitro. Silages (both 60 days and to a lower degree 4 days) showed a lower biohydrogenation compared with fresh and wilted forages, regardless of damaging. This suggests that lipids in ensiled red clover were more protected, but this protection was not enhanced by a higher amount of protein-bound phenols in wilted FT compared with ND red clover. The reduction of rumen microbial biohydrogenation with duration of red clover ensiling seems in contrast to what is expected, namely a higher biohydrogenation when a higher amount of FFA is present. This merits further investigation in relation to strategies to activate PPO toward the embedding of lipids in phenol-protein complexes.Keywords: polyphenol oxidase, fatty acid, PUFA, biohydrogenation, lipolysis ImplicationsRed clover polyphenol oxidase (PPO) has the potential to protect lipids against lipolysis in silage and lipolysis and biohydrogenation in the rumen, leading to higher concentrations of polyunsaturated fatty acids in ruminant meat and milk. PPO is a stress-activated enzyme, which is active in red clover. The goal of this paper was to study the effect of PPO activity due to damaging after mowing, measured as an increase in protein-bound phenols, and wilting duration on lipid metabolism in the silage, mainly lipolysis, and lipolysis and biohydrogenation in the rumen.

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“…Significant differences were found between pasture and grain-fed animal's fatty acid composition with higher polyunsaturated fatty acid concentrations in pasture fed groups. (Chilliard, Ferlay, & Doreau, 2001;Dewhurst, Shingfield, Lee, & Scollan, 2006;Lourenço, Van Ranst, Vlaeminck, De Smet, & Fievez, 2008). Eriksson and Pickova (2007) suggested that fresh grass exerts a greater protection against rumen bacteria for polyunsaturated fatty acids than grains and it is also important to consider the presence of other secondary metabolites that could inhibit microbial biohydrogenation (Lourenço et al, 2008).…”

Section: Fatty Acid Compositionmentioning

confidence: 99%

Meat nutritional composition and nutritive role in the human diet

2013

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a b s t r a c t a r t i c l e i n f oMeat has exerted a crucial role in human evolution and is an important component of a healthy and well balanced diet due to its nutritional richness. The present review attempts to sum up meats role and importance in human nutrition as well as examine some pejorative beliefs about meat consumption. Meat is a valuable source of high biological value protein, iron, vitamin B12 as well as other B complex vitamins, zinc, selenium and phosphorus. Fat content and fatty acid profile, a constant matter of concern when referring to meat consumption, is highly dependent on species, feeding system as well as the cut used. Pork meat can have the highest fat content but poultry skin is not far behind. It is also crucial to distinguish meat cuts from other meat products especially regarding its association with disease risk. As in other dietary components, moderation is advisable but meat has been shown to be an important component of a balanced diet.

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Influence of different dietary forages on the fatty acid composition of rumen digesta as well as ruminant meat and milk

Cited by 118 publications

References 66 publications

Red clover polyphenol oxidase and lipid metabolism

Red clover polyphenol oxidase and lipid metabolism

Influence of damaging and wilting red clover on lipid metabolism during ensiling and in vitro rumen incubation

Meat nutritional composition and nutritive role in the human diet

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