Progress 10/01/04 to 09/30/06
Outputs
To date, our studies examining the effects of nutrient restriction and dietary Se on maternal and fetal visceral organs, placental tissues and mammary tissues have shown that alone, or in combination can alter weights, cellularity and potential function of the maternal system and offspring. Concentrating on the placenta, we have demonstrated that diet may influence placental function. The effects of maternal nutrient restriction and dietary Se on placentome development and cellular proliferation, pregnant Targhee-cross ewe lambs were randomly allotted to one of four treatments in a 2 x 2 factorial arrangement. Factors were nutrition (maintenance [M] vs. 60% maintenance [R]) and dietary Se (no added Se, 7.4 ug/kg BW [NSe] vs. Se-enriched yeast, 81.5 ug/kg BW [HSe]). Selenium treatments were initiated 21 d before breeding and nutritional restriction on d 64 of gestation. All diets were similar in CP (16%) and energy density (2.12 Mcal/kg). At slaughter (d 135 +/- 5 of
gestation), the gravid uterus and its components were removed, weighed, frozen and/or perfuse-fixed with Carnoy's fixative. There was no effect of diet on placentome number or weight, caruncular (CAR) or cotyledonary (COT) tissue weights, CAR cellular proliferation, CAR DNA, CAR RNA, CAR or COT RNA:DNA, CAR protein concentration, or CAR protein:DNA. There were nutritional effects on gravid uterine weight and empty uterine weight, with M-ewes having heavier gravid and empty uterine weights compared to R-ewes (9.9 vs. 8.7 +/- 0.27 kg; 0.81 vs. 0.68 +/- 0.02 kg). M-ewes also had greater COT protein compared to R-ewes (P = 0.05; 50.9 vs. 42.7 +/- 1.95 mg/g). There was a tendency for an increase in the number of proliferating COT cells in HSe-ewes compared to NSe-ewes (P = 0.08; 6.6 vs. 4.0 +/- 0.65) and in R-ewes compared to M-ewes (P = 0.08; 6.5 vs. 4.1 +/- 0.65). R-ewes had higher COT RNA (P = 0.06; 4.3 vs. 3.7 +/- 0.17 mg/g) and COT Protein:DNA (P = 0.06; 15.8 vs.12.4 +/- 0.85) when
compared to M-ewes. Both COT RNA and COT DNA tended to be higher in HSe-ewes compared to NSe-ewes (P = 0.09; 4.3 vs. 3.7 +/- 0.17 mg/g; P = 0.09; 3.9 vs. 3.1 +/- 0.2 mg/g). While there was no Se by nutrition interaction, fetuses from HSe-ewes were heavier compared to the NSe-ewes (P = 0.08; 4.03 vs. 3.63 +/- 0.16 kg) and fetuses in M-ewes were heavier compared to the R-ewes (P = 0.06; 4.05 vs. 3.62 +/- 0.16 kg). It appears that moderate intake and/or supplemental Se tends to increase fetal weights in the absence of an increase in placental, CAR, or COT wt. However, these nutritional treatments during pregnancy may influence the cellularity and function of the placenta. We are currently looking at factors associated with angiogenesis and vascular development in these placentomes. Data on how the fetus has been impacted has also been reported in abstracts and manuscripts listed below.
Impacts
Our data suggests that supernutritional Se intake and nutritional level may impact the physiology of the maternal and fetal systems. There is a real potential for ruminants grazing in the north central region of the US to experience prolonged periods of undernutrition during the first two thirds of gestation both in the absence and presence of selenium (Se)-rich forage. Because early gestation is a crucial period for placental and fetal growth and differentiation, maternal high Se and/or nutrient deprivation during this critical period may inhibit subsequent growth and thereby, alter carcass composition of the offspring. To date, no research in any livestock species has been conducted to evaluate, in parallel, the impacts of maternal undernutrition coupled with a specific nutrient such as Se on growth and vascularization of maternal intestine, uteroplacenta and mammary gland. Alterations in placentomal vascular development and function may impact nutrient delivery to
the growing fetus, potentially affecting the subsequent health, growth efficiency, and carcass quality of their offspring, which will have direct relevance to the animal production industries. Decreased growth rate and sub-optimal carcasses cost livestock producers millions of dollars annually. These data will undoubtedly lead to a better understanding of factors limiting in utero fetal growth and development, which could lead to reduced offspring health, production efficiency, and longevity.
Publications
- Reed, J.J., M.A. Ward, K.A. Vonnahme, T.L. Neville, S.L. Julius, P.P. Borowicz, J.B. Taylor, D.A Redmer, A.T. Grazul-Bilska, L.P. Reynolds, J.S. Caton. 2006. Effects of selenium supply and dietary restriction on maternal and fetal body weight, visceral organ mass, celluclarity estimates, and jejunal vascularity in pregnant ewe lambs. Submitted to Journal of Animal Science on December 22, 2006.
- Tedrow, T. R. Weigl, J.S. Caton, D.A. Redmer, L.P. Reynolds, and K.A. Vonnahme. 2007. Effects of maternal nutrition on fetal liver glycogen content in sheep. Accepted for Midwestern Section of ASAS.
- Arndt, W.J., P.B. Borowicz, M.L. Johnson, L.P. Reynolds, and K.A. Vonnahme. 2007. Impacts of placentome type on angiogenic factor expression and vascularity in the ewe. Accepted for Midwestern Section of ASAS.
- Effertz, C.M., J.S. Caton, C.J. Hammer, J.S. Luther, T.L. Neville, J.J. Reed, D.A. Redmer, L.P. Reynolds, K.A. Vonnahme. 2007. Glucose tolerance of offspring born from ewes receiving differing nutritional levels during pregnancy. Accepted for Midwestern Section of ASAS.
- Lekatz, L., J.S. Caton, P.B. Borowicz, D.A. Redmer, L.P. Reynolds, K.A. Vonnahme. 2007. Effects of maternal selenium and dietary restriction on placentome development and proliferation. Accepted for Midwestern Section of ASAS.
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Progress 10/01/04 to 09/30/05
Outputs
OBJECTIVE 1 Specific Objective 1A: Gravid uterine mass was reduced by nutrient restriction during gestation. This effect seems to be driven by nutrient restriction during the last third of gestation. Fetal weight is also reduced by nutrient restriction and data from the first experiment indicates that levels of selenium may spare fetal tissue loss and body weight loss in ewes that were nutrient restricted during the last two thirds of gestation. Total proliferating cells within the jejunum is increased with supranutritional levels of selenium; however, this response in inconsistent and appears to be related to level of intake and/or rate of gain. Maternal jejunal mucosal DNA (concentrations and contents) were lower in ewes fed nutrient restricted diets from 50 to 95 d of gestation. Maternal intestinal vascularity was not greatly altered by selenium or nutritional treatment. Mammary gland mass is reduced by nutrient restriction. Specific Objective 1B: Supporting
studies under this objective have been complete and data are being summarized. Maternal intestinal vascularity was reduced by nutrient restriction and unaffected by selenium treatment. A major experiment under this objective is scheduled to be initiated in the fall of 2006 with terminal tissue sampling in Spring of 2007 Specific Objective 1C: Pregnant ewes for this study are being delivered as this report is being typed. Ewes are expected to lamb in April. Ewe tissue data will be collected with 24 h of parturition and lambs raised on a common teat-bucked system. Tissue sampling associated with the lamb portion of this study will be conducted in the fall of 2006 Specific Objective 1D: Research under this objective has been initiated with collaborators. Offspring should be ready for terminal phases of the experiment in the fall of 2006. Diets used are very applied with differences in intake being accomplished via changes in both volume and density. OBJECTIVE 2 First set of tissue for
Objective 1 was collected in winter of 2004-05 from 16 ewes. In 13 out of 16 ewes, 3 of the 4 different placentome types were obtained. For Objective 1, the entire gravid uterus was perfuse fixed with Carnoys fixative and embedded in paraffin for immunohistochemistry and image analysis procedures. A graduate student was hired onto the project in fall 2005. Image analysis for the detection for cellular proliferation of the maternal (caruncular; CAR) and fetal (cotyledonary; COT) placenta have been performed and evaluated. CAR vascularity has been complete and is being presented at the Midwest American Society of Animal Science meetings this March. COT vascularity is near completion and statistical analysis will be performed by the end of the month. Tissues for objective 2 are being collected currently. Placental perfusion to test vascular reactivity is currently underway. It appears that there is no difference of morphological type on vascularity of the CAR. Preliminary data support
that the same is true in the COT. Proliferation rate between Type A, B, C and D do not differ. It appears that size, not morphological type, is important for total vascularity of the placenta in the pregnant ewe.
Impacts
There is a real potential for ruminants grazing in the north central region of the US to experience prolonged periods of undernutrition during the first two thirds of gestation both in the absence and presence of selenium (Se)-rich forage. Because early gestation is a crucial period for placental and fetal growth and differentiation, maternal high Se and/or nutrient deprivation during this critical period may inhibit subsequent growth and thereby, alter carcass composition of the offspring. To date, no research in any livestock species has been conducted to evaluate, in parallel, the impacts of maternal undernutrition coupled with a specific nutrient such as Se on growth and vascularization of maternal intestine, uteroplacenta and mammary gland. Future technologies based on basic information provided from the proposed research could be used to optimize maternal-fetal nutrient exchange and fetal development and subsequent longevity, productivity, and marketability of
livestock. Alterations in placentomal vascular development and function may impact nutrient delivery to the growing fetus, potentially affecting the subsequent health, growth efficiency, and carcass quality of their offspring, which will have direct relevance to the animal production industries. Decreased growth rate and sub-optimal carcasses cost livestock producers millions of dollars annually. These data will undoubtedly lead to a better understanding of factors limiting in utero fetal growth and development, which could lead to reduced offspring health, production efficiency, and longevity.
Publications
- Reynolds, L. P., M. E. Biondini, P. P. Borowicz, K. A. Vonnahme, J. S. Caton, and D. L. Redmer. 2005. Functional significance of developmental changes in placental microvascular architecture: The sheep as a model (Invited). Endothelium. 12:11-19.
- Reynolds, L. P., P. P. Borowicz, K. A. Vonnahme, M. L. Johnson, A. T. Grazul-Bilska, J. M. Wallace, J. S. Caton, and D. A. Redmer. 2005 (Invited). Animal models of placental angiogenesis. Plancenta. 26:689-708.
- Borowicz, P. P., J. S. Caton, K. A. Vonnahme, M. A. Ward, E. Borowczyk, A. T. Grazul-Bilska, D. A. Redmer, and L. P. Reynolds. 2005. Effect of maternal age at first pregnancy on fetal and placental growth in Columbia and Romanov ewes. J. Anim. Sci. 83(Suppl. 1):24.
- Borowicz, P., M. Ward, J. Caton, S. A. Soto-Navarro, D. Redmer, J. Taylor, and L. Reynolds. 2005. Effects of supernutritional levels of selenium (Se) on Vascular density and cell proliferation in the sheep placenta. J. Anim. Sci. 83(Suppl. 2):..
- Borowicz PP, Vonnahme KA, Grazul-Bilska AT, Redmer DA, Johnson ML, Reynolds LP. 2005. The effect of maternal age (age at first pregnancy) on placental expression of the major angiogenic factors and their receptors. J. Soc. Gynecol. Invest. 12(Suppl. 1):327A-328A (Abstr. 763).
- Julius, S. L., J. S. Caton, M. A. Ward, S. A. Soto-Navarro, D. A. Redmer, K. A. Vonnahme, P. P. Borowicz, J. B. Taylor, and L. P. Reynolds. 2005. Effect of level and source of selenium on growth and cellular proliferation of maternal jejunal tissue in growing pregnant ewe lambs. Proc. West Sec. Amer. Soc. Anim. Sci. 56:352-355.
- Vonnahme K.A., M.E. Wilson, Y. Li, H.L. Rupnow, T.M. Phernetton, S.P. Ford, R.R. Magness. 2005. Circulating levels of nitric oxide and vascular endothelial growth factor throughout ovine pregnancy. J Physiol. 565:101-109.
- Ward. M., J. Caton, J. Taylor, S. Soto-Navarro, K. Vonnahme, J. Reed, D. Redmer, and L. Reynolds. 2005. Effect of level and source of dietary Se on Se concentrations in maternal and fetal tissues of pregnant ewe lambs during late gestation. Proc. West Sec. Amer. Soc. Anim. Sci. 56:413-416
- Ward, M., J. Caton, J. Taylor, J. Reed, P. Borowicz, A. Grazul-Bilska, K, Vonnahme, D. Redmer, L, Reynolds, 2005. Effects of nutrient restriction and dietary Se on growth and estimates of cellularity in jejunal, placental, and mammary tissues in pregnant ewe lambs. Proc. West Sec. Amer. Soc. Anim. Sci. 56:417-420.
- Ghatta S, Tunstall RR, Vonnahme KA, Caton JS, Reynolds LP, ORourke ST. 2005. Maternal nutrient restriction alters vasodilator mechanisms in fetal sheep coronary arteries. Scientific Sessions 2005, American Heart Association. (http://scientificsessions.americanheart.org/portal/scientificsession s/ss/).
- Ford S., C. Sanders, K. Vonnahme, and B. Hess. 2005. Effects of early gestational undernutrition in the cow on fetal growth and placentomal composition. J. Anim. Sci. (Suppl. 1)297.
- Grazul-Bilska A, Borowczyk E, Caton J, Bilski J, Weigl R, Kirsch J, Vonnahme K, Borowicz P, Reynolds L, Redmer D. 2005. Effects of undernutrition on in vitro fertilization (IVF) and early embryonic development in sheep. Biol. Reprod. 72(Suppl. 1): .
- ONeil M, Lardy GP, Reynolds LP, Caton JS, and Vonnahme KA. 2005. Effects of estradiol (E2) and flaxseed meal (FSM) on organ weights in ovariectomized (OVX) ewes. J Anim Sci 83(Suppl. 1):215.
- ONeil M, Lardy GP, Reynolds LP, Caton JS, and Vonnahme KA. 2005. Effects of estradiol (E2) and linseed meal (LSM) on liver weight, protein concentration, and DNA concentration in ovariectomized (OVX) ewes. Proceedings, Western Section, Amer. Soc. Anim. Sci., Las Cruces NM, June; pp. 237-239.
- Ward MA, Caton JS, Taylor JB, Soto-Navarro S, Vonnahme KA, Reed JJ, Redmer DA, and Reynolds LP. 2005. Effect of level and source of Se on Se concentrations in maternal and fetal tissues of pregnant yearling ewes. Proceedings, Western Section, Amer. Soc. Anim. Sci., Las Cruces NM, June; pp. 413-416.
- Grazul-Bilska AT, Arndt WJ, Caton JS, Borowczyk E, Borowicz PP, Ward MA, Redmer DA, Reynolds LP, Vonnahme KA. 2006. Cellular proliferation in fetal ovarian follicles from late pregnant sheep fed maintenance or restricted diets with normal or enhanced selenium concentrations. Proceedings, 32nd Annu. Conf. Internat. Embryo Transfer Soc., Orlando FL, January.
- Vonnahme K, Reynolds L, Borowicz P, Miller D, Caton B, Hess B, and Ford S. 2005. Effect of maternal undernutrition on capillary vascularity of the bovine placentome. J Anim Sci 83(Suppl. 1):215.
- Ward MA, Caton JS, Taylor JB, Borowicz PP, Vonnahme KA, Reed JJ, Kapphahn M, Freeberg K, Redmer DA, and Reynolds LP. 2005. Effects of nutrient restriction and dietary selenium on selenium concentrations in maternal and fetal tissues of pregnant ewe lambs. Proceedings, Western Section, Amer. Soc. Anim. Sci., Las Cruces NM, June; pp. 437-441.
- Ward MA, Caton JS, Taylor JB, Hallford DM, Reed JJ, Borowicz PP, Vonnahme KA, Redmer DA, and Reynolds LP. 2005. Effects of nutrient restriction and dietary Se on maternal and fetal metabolic hormones in pregnant ewe lambs. Proceedings, Western Section, Amer. Soc. Anim. Sci., Las Cruces NM, June; pp. 421-425.
- Ward MA, Caton JS, Taylor JB, Reed JJ, Borowicz PP, Grazul-Bilska AT, Vonnahme KA, Redmer DA, and Reynolds LP. 2005. Effects of nutrient restriction and dietary Se on growth and estimates of cellularity in jejunal, placental, and mammary tissues in pregnant ewe lambs. Proceedings, Western Section, Amer. Soc. Anim. Sci., Las Cruces NM, June; pp. 417-420.
- Ward MA, Caton JS, Taylor JB, Reed JJ, Borowicz PP, Vonnahme KA, Redmer DA, and Reynolds LP. 2005. Effects of nutrient restriction and organically bound selenium on maternal and fetal organ mass in pregnant ewe lambs. J Anim Sci 83(Suppl. 1):225.
- Reynolds, L. P. P. P. Broowicx, K. A. Vonnahme, M. L. Hohnson, A. T. Grazul-Bilska, J. M. Wallace, D. A. Redmer, and J. S. Caton, 2005. Placental angiogenesis in sheep models of compromised pregnancy (Invited). J. Physiol. 565:43-58.
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