De Smet, S.

Fievez, Veerle

Lourenço, Marta

Vlaeminck, B.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Influence of Dietary Forages on the Fatty Acid Profile of Rumen Digesta, Milk and Meat Marta Lourenço Ghent University, Belgium B. Vlaeminck Ghent University, Belgium S. De Smet Ghent University, Belgium Veerle Fievez Ghent University, Belgium Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/3-1/23 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]456　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ——— Soil‐Plant‐Animal InterrelationshipsInfluence of dietary forages on the fatty acid profile of rumen digesta , milk and meatLouren毕o M . , V laeminck B . , De Smet S . and Fievez VL aboratory f or A nimal Production and A nimal Product Quality , Ghent University , Proe f hoevestraat 10 , 9090 Melle ,Belgium . Corresponding author摧s E‐mail : marta .lourenco＠ ugent .beKey words : biohydrogenation ; botanically diverse forages ; fatty acids ; plant secondary metabolitesIntroduction Forage feeding increases the n‐３ polyunsaturated fatty acid ( PUFA) content in milk and meat . In particular , cloverand botanically diverse forages have the potential to improve the milk and intramuscular ( IM ) fatty acid ( FA) profile in termsof human nutritional recommendations ( Louren毕o et al . , ２００７) . Here , we intend to integrate literature results on milk and IMFA of dairy cows or lambs fed leguminuous rich or botanically diverse forages as compared to forage products from moreintensively managed grasslands . Information on rumen FA is used to suggest potential explanations for differences in FA endproduct composition .Materials and methods Milk FA results ( proportion of milk total FA) were divided into three data sets : １) red clover ( RC) ( n＝ ６) vs . ryegrass based diets ( n ＝ ６) ; ２ ) white clover (WC) ( n ＝ ７) vs .RC forages ( n ＝ ７) and ３) botanically diverse (BD) ( n＝ ７) vs . grass based diets ( n ＝ ６) , which were compared statistically using a mixed model with study as a random effect andweighing of the variables by the number of observations in each study ( St‐Pierre , ２００１ ) . Studies on dietary forage type inrelation to rumen biohydrogenation ( ４ experiments) and intramuscular FA profile (６ experiments) were too few and diverse tointegrate in an overall statistical analysis and are summarised to give an overview of general trends . The reader is referred toLouren毕o et al . ( ２００７) for the complete reference list of the individual studies .Results and discussion In general , RC forages resulted in lower C１８ .３ n‐３ apparent biohydrogenation ( Figure １ ) , whichwasreflected in higher milk C１８ :３ n‐３ proportions compared to ryegrass forages ( Table １) , despite the similar C１８ :３ n‐３ intake .Nevertheless , long chain PUFA in IM fat remained similar in ruminants fed RC and ryegrass diets ( Figure ２ ) . Compared tograss based diets , feeding BD forages resulted in higher C１８ :３ n‐３ milk proportions ( Table １ ) and IM fat long chain PUFAproportions ( Figure ２ ) , although rumen C１８ :３ n‐３ apparent biohydrogenation did not differ ( data not shown) . Moreover ,higher rumen C１８ :１ t１１ proportions were found for ruminants fed BD forages (４ .５９ g /１００ g FA ) compared to ruminants fedgrass based forages (２ .７２ g /１００ g FA) . It is evident that feeding BD forages affects rumen FA metabolism , but changes couldnot always be associated with differences in the proximate chemical composition of the pastures or their PUFA content . Otherfactors might play a role , such as plant secondary metabolites , but only few for e .g . polyphenol oxidase in RC‐have beenstudied for their effect on rumen FA metabolism .Table 1 C18 :3 n‐3 intake ( g / d) and milk C18 :3 n‐3 p roportions ( g /100 g total milk FA ) in the milk o f dairy cattle f edeither botanically diverse f orage based diets , intensive ryegrass , red or white clover p roducts ( 报P＜ 0 .1 ;倡 P＜ 0 .05 ) .Ryegrass RC WC RC Grass based BDIntake C 18 :3 n‐3 摀92 �.1 115 B.6 136 è171报 147 s116 刎Milk C 18 :3 n‐3 X0 憫.555 1 鲻.05 倡 0 \.956 0 亮.893 0 '.788 1 寣.06 倡Figure 1 C18 :3 n‐3 ap p arent biohydrogenation ( g /100g) f or ryegrass , RC and WC f orages ( adap tedf rom Louren毕o et al . , 2007) 报 P ＜ 0 .1 ; 倡 P ＜ 0 .05 .Figure 2 Ratio o f the p roportions o f totalPUFA in the IM f at o f animals f ed RC toryegrass and f ed BD to grass based f orages( adap ted f rom Louren毕o et al . , 2007) 倡 P ＜0 .05 .Conclusions Botanically diverse forages have the potential to change the PUFA content of ruminant products , which isassociated with changes in the rumen and animal endogenous FA metabolism . Plant secondary metabolites are hypothesized tocause the observed differences , but more research on this topic is needed .90 80 70-l----l=-"--'-----,--J===-~="'""'~~~~-~ Exp. 1 Exp. 2 Exp. 3 Exp. 4 ea Ryegrass " RC .. we 2 0 RC vs. Ryegrass BD vs. grass rn Exp.A Ill Exp. B lil Exp. C □ Exp. D m Exp. E ei Exp. F 

Influence of Dietary Forages on the Fatty Acid Profile of Rumen Digesta, Milk and Meat

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Influence of Dietary Forages on the Fatty Acid Profile of Rumen Digesta, Milk and Meat

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