REPRODUCTION RESEARCH Neonatal hormone changes and growth in lambs born to dams receiving differing nutritional intakes and selenium supplementation during gestation Leticia E Camacho, Allison M Meyer, Tammi L Neville, Carolyn J Hammer, Dale A Redmer, Lawrence P Reynolds, Joel S Caton and Kimberly A Vonnahme Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, North Dakota 58108, USA Correspondence should be addressed to K A Vonnahme; Email: kim.vonnahme@ndsu.edu A M Meyer is now at Department of Animal Science, University of Wyoming, Laramie, Wyoming Abstract To investigate the effects of maternal selenium (Se) supplementation and nutritional intake during gestation on hormone changes, percentage body weight (BW) change, and organ mass in neonatal lambs, ewes were allocated to differing Se levels (adequate Se (ASe, 11.5 mg/kg BW) or high Se (HSe, 77.0 mg/kg BW)) initiated at breeding and nutritional intake (60% (RES), 100% (CON), or 140% (HIGH) of NRC requirements) initiated at day 40 of gestation. At parturition, all lambs were removed from dams, fed common diets, and BW and blood samples were collected until day 19. There was a Se!nutritional intake!day interaction for percentage BW change from birth. Lambs born to ASe-HIGH ewes tended to have decreased BW change compared with ASe-CON and ASe-RES groups on day 7. Lambs from HSe-HIGH ewes tended to have increased BW change compared with HSe-RES and HSe-CON groups from days 7 to 19. At birth, there was a Se!sex of offspring interaction, in which male lambs from HSe ewes had decreased cortisol concentrations compared with all other lambs. By 24 h, lambs from RES ewes had decreased cortisol compared with those from HIGH ewes, with lambs from CON ewes being intermediate. Lambs from RES- and CON-fed ewes had greater thyroxine than HIGH ewes at 24 h. Organ masses on day 19 were mainly impacted by maternal nutritional intake and sex of the offspring. Birth weight alone did not predict growth performance during neonatal life. Moreover, despite a similar postnatal diet, maternal nutritional plane and Se status did impact neonatal endocrine profiles. Exact mechanisms of how neonatal endocrine status can influence later growth and development need to be determined. Reproduction (2012) 144 23–35 Introduction Maternal nutrition during pregnancy plays an important role in supporting adequate fetal and placental growth and development. Intrauterine growth restriction (IUGR) is associated with altered fetal organ development and subsequent performance of offspring (Wu et al. 2006, Neville et al. 2010, Reynolds et al. 2010, Vonnahme et al. 2010). Our laboratory has reported that maternal nutrient restriction during mid-to-late gestation in ewes decreased fetal body weight (BW; Reed et al. 2007) as well as birth weight (Neville et al. 2010). However, ewes given supranutritional selenium (Se) levels had greater fetal BW compared with ewes receiving adequate Se (ASe) levels (Reed et al. 2007). IUGR is associated with accelerated growth and increased adiposity in the early neonatal period; although the mechanisms are unknown, they could include altered secretion or metabolism of thyroid hormones (DeBlasio et al. 2006). DeBlasio et al. (2006) suggested that placental restriction and small size at birth may increase activation of thyroxine (T 4 ) to triiodothyronine (T 3 ) and sensitivity of soft tissue to thyroid hormones, which may contribute to the accelerated neonatal growth following IUGR. Moreover, T 4 is positively correlated with size at birth (DeBlasio et al. 2006). Additionally, Mellor & Pearson (1977) demonstrated a positive correlation between lamb BW and concentrations of T 4 at birth, which could be reflected by the effects of T 4 on fetal growth. Glucocorticoids have major effects on the differen- tiation, morphology, and function of numerous tissues including the lungs, liver, kidneys, muscle, fat, and gastrointestinal tract (Challis et al. 2000, Fowden & Forhead 2004). Glucocorticoids may also be essential for survival postnatally, as they induce maturation of several organs, including fetal lungs, brain, and gastrointestinal tract (Challis et al. 2000, Fowden & Forhead 2004). q 2012 Society for Reproduction and Fertility DOI: 10.1530/REP-11-0302 ISSN 1470–1626 (paper) 1741–7899 (online) Online version via www.reproduction-online.org Downloaded from Bioscientifica.com at 12/10/2018 09:34:25PM via free access