Metabolism of flaxseed lignans in dairy cows

N. Gagnon¹*, C. Côrtes¹, D. C. da Silva^1,2, R. Kazama^1,2, G. T. dos Santos², L. M. Zeoula² and H. V. Petit¹, ¹Agriculture and Agri-Food Sherbrook e-QC, Canada. ²Universidade Estadual de Maringá, Brazil and CNPq Brazil.

ABSTRACT

Flaxseed is the richest source of plant lignan secoisolariciresinol diglucoside (SDG), which is a precursor of the mammalian lignans, enterodiol (ED) and enterolactone (EL). The objective of the experiment was to study the effects of the site of administration of flaxseed oil (rumen and abomasum) and flax hulls (rumen and abomasum) on the concentration of EL in rumen, blood, urine, and milk. Four lactating dairy cows were used in a 4 X 4 Latin square design with 21-d periods. Flax hulls (1800 g/d) and oil (400 g/d) were placed in the rumen three times daily or infused continuously in the abomasum. Treatments were: 1) oil and hulls placed in the rumen + abomasal infusion of water; 2) oil and hulls infused in the abomasum; 3) oil infused in the abomasum and hulls placed in the rumen; and 4) oil placed in the rumen + hulls infused in the abomasum. Concentration of EL in pooled samples (2, 4, and 6 h) of ruminal fluid was higher for cows supplemented with hulls in the rumen than for those infused with hulls in the abomasum. The concentration of EL was significantly higher in urine, plasma, and milk samples of cows with ruminal supplementation of hulls than in samples of cows infused with hulls in the abomasum. This would suggest that the rumen plays an important role for the in vivo metabolism of flax lignans to mammalian lignans and contributes to increase EL concentration into milk.