Genistein Alters the Release of Oxytocin, Prostaglandins, Cortisol and LH during Insemination in Gilts

Abstract

Soya products containing phytooestrogens are widely used as feed for pigs. However, limited data are available on the effects of phytooestrogen on the endocrine status of pigs. The aim of this work was to study the impact of the phytooestrogen genistein added to a soya-free diet on the hormonal pattern in gilts during oestrus and artificial insemination (AI). Ten gilts were fed a soya-free diet and fitted with jugular vein catheter through vena auricularis. The gilts were randomly divided into two groups (G- and C-group) where the G-group was given pure genistein, 1 mg/kg body weight (BW) twice daily, per os. Blood samples were collected before, during and after AI. Oxytocin, prostaglandin E₂, prostaglandin F₂(α), 13,14-dihydro-15-keto-prostaglandin F₂(α) (PGFM), cortisol and LH concentrations in blood plasma were analysed. Oxytocin concentrations were almost twice as high in the G-group as in C-group after the AI. Prostaglandin E₂ concentrations were higher in G-group than in C-group during the entire sampling period. After AI, the concentrations of prostaglandin E₂ increased in G-group but not in C-group. Prostaglandin F₂(α) concentration had a pulsatile pattern, with increasing pulses after AI in G-group. Plasma PGFM concentrations increased after AI with a small variation between the groups. Plasma cortisol concentration increased after AI in C-group. LH decreased after AI in G-group. Genistein stimulated elevations of plasma oxytocin and prostaglandin E₂ concentrations and a pulsative pattern in prostaglandin F₂(α) concentration. The possible involvement of genistein in plasma cortisol and basal LH concentrations in gilts given genistein may also be suggested.