Variety, time of harvest and conditions during growing season have impact on red clover isoflavone content

Eeva Arja Mustonen,Mikko Tuori,Aila Vanhatalo,Mika Isolahti,Päivi Kurki,Juhani Taponen

doi:10.23986/afsci.69781

Eeva Arja Mustonen, Mikko Tuori + Show 4 more

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https://doi.org/10.23986/afsci.69781

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Abstract

Red clover (Trifolium pratense L.) is the predominant legume used in northern European agriculture. Official red clover variety trials are conducted by Natural Resources Institute Finland (Luke) to determine the value of field crop varieties. The trials used for the current analysis were conducted in Luke units in southern Finland (Mikkeli) and northern Finland (Ruukki) in two consecutive years. Plant samples for isoflavone analyses were collected from four varieties grown as four replicates and harvested twice during both growing seasons. The four main isoflavones biochanin A, genistein, daidzein and formononetin were analysed using high performance liquid chromatography. Total phytoestrogen content in the varieties varied in the range of 11.2−14.8 mg g-1 dry matter (DM). The variety and the time of harvest had most effect on the isoflavone, especially formononetin, contents of red clover. A more northern growing area and challenging weather conditions were associated with increased isoflavone concentrations.

Highlights

There is growing interest in using forage legumes for ruminant feeding in organic as well as in conventional agriculture
The main isoflavones in red clover varieties were formononetin, varying in range of 5.95−7.89 mg g-1 in dry matter (DM), followed by biochanin A varying in range of 3.66−6.07 mg g-1 in DM
The isoflavone contents found in this study are in line with those from previous studies, for example, total isoflavone content in Finnish red clover silages were at 10−25 mg g-1 in DM and formononetin content at 7−10 mg g-1 in DM (Kallela et al 1988, Saloniemi et al 1995)

Summary

Introduction

There is growing interest in using forage legumes for ruminant feeding in organic as well as in conventional agriculture. In comparison with grass silage, red clover silage can stimulate higher dry matter intake and milk yield in dairy cows (Dewhurst et al 2003, Bertilsson and Murphy 2003, Vanhatalo et al 2006, Johansen et al 2017). Replacing grass silage with red clover silage can lead to desirable changes in milk fatty acid composition (Dewhurst et al 2003, Bertilsson and Murphy 2003, Vanhatalo et al 2006, Vanhatalo et al 2007). Red clover diets promote growth and increase live weight gain in ewes and in lambs (Fraser et al 2004, Moorby et al 2004, Speijers et al 2005, Graves et al 2012)

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