Effects of selenium supply and dietary restriction on maternal and fetal metabolic hormones in pregnant ewe lambs

Center for Nutrition and Pregnancy and Animal and Range Sciences Department, North Dakota State University, Fargo 58105, USA.
Journal of Animal Science (Impact Factor: 2.11). 05/2008; 86(5):1254-62. DOI: 10.2527/jas.2007-0509
Source: PubMed


The objective of these studies was to evaluate the effects of dietary restriction and Se on maternal and fetal metabolic hormones. In Exp. 1, pregnant ewe lambs (n = 32; BW = 45.6 +/- 2.3 kg) were allotted randomly to 1 of 4 treatments. Diets contained (DM basis) either no added Se (control), or supranutritional Se added as high-Se wheat at 3.0 mg/kg (Se-wheat), or sodium selenate at 3 (Se3) and 15 (Se15) mg/kg of Se. Diets (DM basis) were similar in CP (15.5%) and ME (2.68 Mcal/kg). Treatments were initiated at 50 +/- 5 d of gestation. The control, Se-wheat, Se3, and Se15 treatments provided 2.5, 75, 75, and 375 microg/kg of BW of Se, respectively. Ewe jugular blood samples were collected at 50, 64, 78, 92, 106, 120, and 134 d of gestation. Fetal serum samples were collected at necropsy on d 134. In Exp. 2, pregnant ewe lambs (n = 36; BW 53.8 +/- 1.3 kg) were allotted randomly to treatments in a 2 x 2 factorial arrangement. Factors were nutrition (control, 100% of requirements vs. restricted nutrition, 60% of control) and dietary Se (adequate Se, 6 microg/kg of BW vs. high Se, 80 microg/kg of BW). Selenium treatments were initiated 21 d before breeding, and nutritional treatments were initiated on d 64 of gestation. Diets were 16% CP and 2.12 Mcal/kg of ME (DM basis). Blood samples were collected from the ewes at 62, 76, 90, 104, 118, 132, and 135 d of gestation. Fetal blood was collected at necropsy on d 135. In Exp.1, dietary Se source and concentration had no effect (P > 0.17) on maternal and fetal serum IGF-I, triiodothyronine (T(3)), or thyroxine (T(4)) concentrations. Selenium supplementation increased (P = 0.06) the T(4):T(3) ratio vs. controls. In Exp. 2, dietary Se had no impact (P > 0.33) on main effect means for maternal and fetal serum IGF-I, T(3), or T(4) concentrations from d 62 to 132; however, at d 135, high-Se ewes had lower (P = 0.01) serum T(4) concentrations than adequate-Se ewes. A nutrition by Se interaction (P = 0.06) was detected for the T(4):T(3) ratios; ewes fed restricted and adequate-Se diets had greater (P = 0.10) T(4):T(3) ratios compared with the other treatments. Nutrient-restricted ewes had lower (P < 0.05) serum IGF-I, T(3), and T(4) concentrations. Fetal serum IGF-I concentrations were lower (P = 0.01) in restricted-vs. control-fed ewes; however, fetal T(3) and T(4) concentrations were unaffected (P > 0.13) by dietary Se or maternal plane of nutrition. These data indicate that dietary Se may alter maternal T(4):T(3) ratios. In addition, nutrient restriction during gestation reduces maternal IGF-I, T(3), and T(4) and fetal IGF-I concentrations.

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Available from: Kimberly A Vonnahme
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    • "However, whether Se intake is important for IGF biological activity has not been studied extensively, despite the relationship between T 3 and the hypothalamic–GH–IGF axis (Miell et al. 1993). An association between low Se intake and low IGF1 serum values in adults and children has been reported (Aydin et al. 2002, Maggio et al. 2010), yet Se supplementation in gestating ruminants does not affect IGF1 concentration in their offspring (Ward et al. 2008, Gunter et al. 2013). "
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    ABSTRACT: Selenium (Se), an essential trace metal, is important in both growth and reproduction and is the constituent of different selenoproteins. The glutathione peroxidase (GPx) family is the most studied as it prevents oxidative stress. Liver oxidation is considered as another mechanism involved in low birth weight. Therefore in order to ascertain whether GPx is related to the effects of Se on growth during gestation and lactation, three groups of rat pups were used: control, Se-deficient and Se-supplemented. Morphological parameters and reproductive indices were evaluated. Hepatic Se levels were measured by graphite-furnace atomic absorption while spectrophotometry was used for activity of antioxidant enzymes and oxidative stress markers in liver; and western blotting for expression of hepatic GPx1 and GPx4. The Se-deficient diet increased mortality at birth, decreased viability and survival indices and stunted growth, length and liver development in offspring, thus decreasing hepatic Se levels, GPx, glutathione reductase and catalase activities, while increased superoxide dismutase activity and protein oxidation. The Se-supplemented diet counteracted all of the above results. GPx1 expression was heavily regulated by Se dietary intake; however, although Se dietary deficiency reduced GPx4 expression, this decrease was not as pronounced. Therefore, it can be concluded that Se dietary intake is intimately related to growth, length, and directly regulating GPx activity primarily via GPx1, and secondly to GPx4, thus affecting liver oxidation and development. These results suggesting that if risk of uterine growth retardation is suspected, or neonates with low birth weight presents signs of liver oxidation, may be beneficial know about Se status.
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    • "In this research model, nutritional plane during gestation has affected ewe endocrine profiles. Nutrient-restricted ewes had decreased IGF-I (Ward et al., 2008), progesterone (Vonnahme et al., 2007; Lekatz et al., 2010), and thyroid hormones (Ward et al., 2008; Lekatz et al., 2010), whereas ewes fed a high nutritional plane had decreased estradiol and progesterone but increased prolactin (Camacho et al., 2010) and cortisol (Vonnahme et al., 2007) during gestation. These alterations in hormones likely interact to play a role during the crucial mammary growth and development of gestation (Mellor et al., 1987; Banchero et al., 2006). "
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    ABSTRACT: The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed individually from d 40, and lambs were removed at parturition. Colostrum was milked from all ewes at 3 h postpartum, and one-half of the ewes (n = 42) were transitioned to a common diet meeting lactation requirements and mechanically milked for 20 d. Colostrum yield was greater (P = 0.02) for HSe ewes than ASe, whereas CON had greater (P < 0.05) colostrum yield than RES and HIH. Colostrum Se (%) was greater (P < 0.01) for HSe than ASe. Colostrum from ewes fed HSe had less (P = 0.03) butterfat (%), but greater (P ≤ 0.05) total butterfat, solids-not-fat, lactose, protein, milk urea N, and Se than ASe. Colostrum from HIH ewes had greater (P ≤ 0.02) solids-not-fat (%) than RES, whereas RES had greater (P ≤ 0.04) butterfat (%) than CON and HIH. Colostrum from ewes fed the CON diet had greater (P = 0.01) total butterfat than HIH. Total solids-not-fat, lactose, and protein were greater (P < 0.05) in colostrum from CON than RES and HIH. Ewes fed HSe had greater (P < 0.01) milk yield (g/d and mL/d) than ASe, and CON and HIH had greater (P < 0.01) yield than RES. Milk protein (%) was greater (P ≤ 0.01) in RES compared with CON or HIH. Ewes fed HSe had greater (P < 0.01) milk Se (µg/g and mg/d) than ASe on each sampling day. Milk from CON and HIH ewes had greater (P < 0.01) total solids-not-fat, lactose, protein, and milk urea N than RES. Total Se was greater (P = 0.02) in milk from ewes fed the CON diet compared with RES. Somatic cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.
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    ABSTRACT: The objective of this study was to evaluate embryonic and fetal growth by ultrasonographic measurements in pregnant Akkaraman ewes fed a maintained diet either given or not given supplemental selenium (Se) and vitamin E (vit E). Thirteen pregnant ewes were allotted to two groups, a group of 5 ewes supplemented with Se and vit E and a group of 8 ewes not supplemented. The supplemented group received barley plus straw and 0,1 ppm Se per kg -15 IU vitE per kg DM from 9 months prior to breeding season until 40 day after parturition. The other group was fed with the same protocol without Se and vit E supplementation. The different structures of ovine fetuses were measured by ultrasonography from day 15 until day 130 of gestation. Suitable regression models were used for each group at the advanced pregnancy, through taking the biparietal diameter (BPD), diameters of orbita, stomach, heart, trunkus, abdomen, femur, humerus, radius-ulna, tibia-fibula and countable caruncle and relationship between the period of pregnancy and fetal growth. The mean serum Se levels of Se and vit E unsupplemented and supplemented groups were 120.6 ng per ml (SE 3.7) and 211.3 ng per ml (SE 11.5), respectively. BPD, diameters of fetal heart, abdomen, trunk, stomach, orbit diameter, the length of extremites and caruncle measurements were not affected by maternal serum Se level. All ultrasonographic measurements in both groups exhibited linear or exponential increase as corraleted with the advancement of pregnancy. The results obtained from this study indicated that maternal serum Se concentration from 112.9 ng per ml to 235.1 ng per ml during pregnancy had neither negative nor positive effect on embryonic and fetal growth.
    No preview · Article · Dec 2008 · Revue de médecine vétérinaire
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