Ilkka Saastamoinen

Phytoestrogen Content and Estrogenic Effect of Legume Fodder

Abstract This study is a summary of Finnish investigations of the phytoestrogen content of legume plants, red clover, white clover, alfalfa, and goats rue. In addition to the chemical analyses, biological studies were performed. Uterine weight of immature rats was used as an indicator of the estrogenic effect of the fodder used. All red clover varieties studied contained estrogenic isoflavones, especially formononetin and biochanin-A. The phytoestrogen content varied from 1.0% to 2.5% of dry matter. The biological study of white clover showed a clear estrogenic effect not visible through chemical analysis. Alfalfa contains small quantities of formononetin and biochanin-A, but 25-65 ppm coumestrol in dry matter. The estrogenic effect of alfalfa was obvious in the biological study. Goats rue did not contain any known phytoestrogens, and the biological study was completely negative.

Effects of intraruminal infusions of propionate and butyrate with two different protein supplements on milk production and blood metabolites in dairy cows receiving grass silage-based diet

Four cows were used in a balanced 4 x 4 Latin square with 2 week experimental periods to investigate the effects of intraruminal infusions of volatile fatty acids and protein source on milk production and blood metabolites. The four treatments in a 2 x 2 factorial arrangement were isoenergetic intraruminal infusions of propionate (500 g day -1 ) or butyrate (417 g day -1 ) each given with isonitrogenous protein supplementation of fish meal (FM) or barley protein (BP). The cows were fed restrictively with 9 kg dry matter day -1 of formic acid treated grass silage and 8 kg day -1 of concentrate. Propionate infusion increased milk yield (24.9 vs 23.4 kg day -1 ; P < 0.05), milk protein yield (832 vs 778 g day -1 ; P = 0-05) and milk lactose content (44.7 vs 43.5 g kg -1 ; P < 0.05) and yield (1113 vs 1023 g day -1 ; P < 0.01), whereas butyrate infusion was associated with a higher milk fat content (44.7 vs 39.4 g kg -1 ; P < 0.01) and yield (1033 vs 974 g day -1 ; P < 0.01). FM tended (P < 0.10) to increase milk yield, but had no significant effects on milk composition or milk component yields compared with BP. Butyrate infusion increased blood ketones, plasma non-esterified fatty acids and glycine relative to propionate infusion. The concentrations of ammonia N in rumen fluid and urea in plasma and milk were similar for both protein supplements. The profile of amino acids in plasma was similar for both protein supplements except for the higher concentrations of phenylalanine, proline and tyrosine with BP. The results show that protein utilisation can be improved by increasing the supply of propionate from rumen fermentation in cows given a grass silage-based diet.

Equol in milk of dairy cows is derived from forage legumes such as red clover

The intake of isoflavones and the resulting equol contents of both plasma and milk of the same red clover-fed cows are reported for the first time in cyclic change-over design study. Cows were fed four different red clover silages and two timothy-meadow fescue silages as controls. The red clover silages contained daidzein, formononetin, biochanin A and genistein, whereas the timothy-meadow fescue silages contained no isoflavones. We found a strong association (y = 0.071x+2.75, R 2 0.71) between the formononetin intake (x) and equol concentration (y) in the plasma, while the formononetin intake and milk equol concentration were weakly associated (y = 0.0035x+0.358, R 2 0.20). This means that a small part of the total formononetin in the silage is secreted into milk as equol. The mean equol contents in plasma and milk of cows fed red clover silage diets were in the range of 4.6-8.4 mg/l and 458-643 microg/l, respectively, while the respective values for the control diets were in the range of 0.8-1.5 mg/l and 171-287 microg/l. We showed that shorter growing periods of red clover resulted in higher silage formononetin contents and plasma and milk equol contents, suggesting that the equol content of milk can be manipulated by varying the harvesting strategy of red clover. We conclude that milk equol is derived from the formononetin of red clover silage and that milk from red clover-fed cows can be considered as a source of equol in human nutrition.

Phytoestrogen Content of Birdsfoot Trefoil and Red Clover: Effects of Growth Stage and Ensiling Method

The phytoestrogen content of birdsfoot trefoil (Lotus corniculatus L.) and red clover (Trifolium pratense L.) was determined. In addition, the effects of growth stage, wilting and ensiling additives on content were studied. Birdsfoot trefoil raw material and silage contained only traces of phytoestrogens. In red clover raw material and silage, the phytoestrogen content varied from 0.8% to 1.1% of dry matter. Content was affected by growth stage of the plant and wilting. Formononetin concentration decreased as the plant matured from budding to flowering stage, and wilting from 25% to 40% of dry matter content decreased genistein and biochanin A content. The phytoestrogen content of red clover silage was 18% higher than that of raw material. Silage additives also affected the content. Silage ensiled with an additive containing Lactobacillus plantarum bacterial inoculate had higher concentrations of genistein and biochanin A than silage made with formic acid.