The Relationship between Selenium and T3 in Selenium Supplemented and Nonsupplemented Ewes and Their Lambs

Abstract

Twenty pregnant ewes were selected and classified into two groups. The first group received subcutaneous selenium supplementation (0.1 mg of sodium selenite/kg BW) at the 8th and 5th weeks before birth and 1st week after birth while the other was control group without selenium injection. Maternal plasma and serum samples were collected weekly from the 8th week before birth until the 8th week after birth and milk samples were taken from ewes weekly, while plasma and serum samples were collected at 48 hours, 1st, 2nd, 3rd, 5th, and 8th weeks after birth from the newborn lambs. Results demonstrated significant positive relationship between maternal plasma selenium and serum T3 in supplemented and control ewes (r = 0.69 to 0.72, P < 0.05). There was significant (P < 0.001) increase in T3 in supplemented ewes and their lambs until the 8th week after birth. There was positive relationship between milk, selenium concentration, and serum T3 in the newborn lambs of the supplemented group (r = 0.84, P < 0.01), while the relationship was negative in the control one (r = −0.89, P < 0.01). Muscular and thyroid pathological changes were independent of selenium supplementation. Selenium supplementation was important for maintaining T3 in ewes and newborn lambs until the 8th week after birth.

The effect of organic selenium in feeding of ewes in late pregnancy on selenium transfer to progeny

“…Selenium is required for conversion of T4 into the more active T3 via the enzyme type 4 deiodinase (Hefnawy et al, 2014). In our experiment, a higher nutritional dosage of Se did not result in a significantly higher serum fT3 level.…”

“…Nevertheless, no lambs had plasma levels near or above 1400 µg/L, which has been suggested as the level when signs of Se toxicosis appear in sheep (Davis et al, 2006). According to studies in cattle and sheep, various authors (Donald et al, 1994;Awadeh et al, 1998;Rock et al, 2001;Rowntree et al, 2004;Hefnawy et al, 2014) presented results that clearly demonstrate the importance of supplementation to maintain Se and T3 homeostasis in both pregnant ewes and their offspring. Rock et al (2001) demonstrated this condition in pregnant ewes but T3 only presented a tendency to have higher levels in their lambs.…”

“…In our study, transplacental transfer of Se from ewe to lamb was affected by the dose of organic Se. Nutrient transfer from dam to offspring occurs via two pathways: placental transfer and colostrum/milk ingestion (Hefnawy et al, 2014). Selenium placental transfer was demonstrated by De Toledo and Perry (1985) and Stewart et al (2012) and fetal selenium concentrations have been shown to be greater (Stewart et al, 2012) than corresponding maternal selenium concentrations.…”

“…Zootec., 46(2): [147][148][149][150][151][152][153][154][155]2017 as it efficiently passes through the placental barrier into fetal tissues and is also transferred into colostrum and milk (Rock et al, 2001;Stewart et al, 2012). A close relationship has been detected between offspring serum Se and maternal levels after feeding with Se, once the offspring obtains this nutrient via the placenta before birth (Hefnawy et al, 2014). Hefnawy et al (2007) suggested that the allantoic sac plays an important role in homeostasis of nutrients and metabolites and Se concentration of amniotic and allantoic fluids may be used as an indicator of Se status in the fetus throughout gestation.…”

Effect Of Organic Selenium And Iodine Supplementation On Selenium And Thyroid Hormones Status Of Lactating Ewes And Lambs

“…Such decrease is consistent with the results of Head et al [28] and Hewnavy et al [29] and corresponds to ontogenetic dynamic thyroid hormones levels in blood plasma [30]. In contrast with the results of Chadio et al [7] and Kumar et al [31] who did not notice any effect of Se supplementation on lambs thyroid hormone levels, in our experimental period higher Se supplementation in ewes of HSe and HSeI group resulted in signifi cantly higher (P<0.05) lamb plasma thyroid hormones levels up to 30 days post birth.…”