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Martinez RE, Leatherwood JL, Bradbery AN, Paris BL, Hammer CJ, Kelley D, Bazer FW, Wu G. Evaluation of dietary arginine supplementation to increase placental nutrient transporters in aged mares. Transl Anim Sci 2023; 7:txad058. [PMID: 37593152 PMCID: PMC10430792 DOI: 10.1093/tas/txad058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 06/21/2023] [Indexed: 08/19/2023] Open
Abstract
Nine pregnant mares (18.2 ± 0.7 yr; 493.82 ± 12.74 kg body weight [BW]) were used to test the hypothesis that dietary supplementation of l-arginine would enhance placental vascularity and nutrient transport throughout gestation in aged mares. Mares were balanced by age, BW, and stallion pairing, and assigned randomly to dietary treatments of either supplemental l-arginine (50 mg/kg BW; n = 7) or l-alanine (100 mg/kg BW; n = 6; isonitrogenous control). Mares were individually fed concentrate top-dressed with the respective amino acid treatment plus ad libitum access to Coastal Bermudagrass hay. Treatments began on day 14 of gestation and were terminated at parturition. Mare BW, body condition score (BCS), and rump fat were determined, and body fat percentage was calculated every 28 d and concentrate adjusted accordingly. Doppler blood flow measurements including resistance index (RI) and pulsatility index for uterine artery ipsilateral to the pregnant uterine horn were obtained beginning on day 21 and continued every 7 d until day 154 of gestation, and prior to parturition. Parturition was attended with foaling variables and placental measures recorded. Placental tissue from the pregnant horn was analyzed histologically to assess cell-specific localization of vascular endothelial growth factor (VEGF) and cationic amino acid transporter 1 (SLC7A1) proteins. Semiquantitative analyses were performed using 10 nonoverlapping images per sample fixed in a 10× field (Fiji ImageJ v1.2). Mare performance data were analyzed using PROC MIXED in SAS and foaling and placental data were analyzed using PROC GLM. Gestation length at parturition was not influenced (P > 0.05) by supplemental arginine. Compared with arginine-supplemented mares, control mares had a thicker rump fat layer (P < 0.01) and greater percent body fat (P = 0.03), and BCS (P < 0.01) at parturition. Arginine-supplemented mares had a lower RI than control mares prior to parturition (P < 0.01). Body length, height, and BW of foals at birth, as well as placental weight and volume, and immunohistochemical staining for VEGF and SLC7A1 at parturition, were not affected (P > 0.05) by maternal arginine supplementation. These results indicate that dietary arginine supplementation (50 mg/kg BW) is safe for gestating mares. A larger number of mares is required to extend knowledge of effects of supplemental arginine on embryonic/fetal survival and growth in mares.
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Affiliation(s)
- Rafael E Martinez
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- School of Agricultural Sciences, Sam Houston State University, Huntsville, TX 77340, USA
| | - Jessica L Leatherwood
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Amanda N Bradbery
- Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717, USA
| | - Brittany L Paris
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Carolyn J Hammer
- Department of Animal Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Dale Kelley
- Department of Veterinary Clinical Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
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Chavatte-Palmer P, Derisoud E, Robles M. Pregnancy and placental development in horses: an update. Domest Anim Endocrinol 2022; 79:106692. [PMID: 34823139 DOI: 10.1016/j.domaniend.2021.106692] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/03/2022]
Abstract
Horses have been domesticated by man and historical information mostly associates horses with men. Nowadays, however, horse riding is essentially by women. Women are also very much involved in equine sciences, with a large contribution to the understanding of fetoplacental development. While highlighting the work of female scientists, this review describes the recent advances in equine fetoplacental studies, focusing on data obtained by new generation sequencing and progress on the understanding of the role of placental progesterone metabolites throughout gestation. A second emphasis is made on fetal programming, a currently very active field, where the importance of maternal nutrition, mare management or the use of embryo technologies has been shown to induce long term effects in the offspring that might affect progeny's performance. Finally, new perspectives for the study of equine pregnancy are drawn, that will rely on new methodologies applied to molecular explorations and imaging.
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Affiliation(s)
- P Chavatte-Palmer
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France.
| | - E Derisoud
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France
| | - M Robles
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France; INRS Centre Armand-Frappier Santé Biotechnologie, Laval, Québec H7V1B7, Canada
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Clothier J, Small A, Hinch G, Brown WY. Perinatal Stress in Immature Foals May Lead to Subclinical Adrenocortical Dysregulation in Adult Horses: Pilot Study. J Equine Vet Sci 2022; 111:103869. [DOI: 10.1016/j.jevs.2022.103869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/21/2021] [Accepted: 01/17/2022] [Indexed: 11/17/2022]
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Robles M, Hammer C, Staniar B, Chavatte-Palmer P. Nutrition of Broodmares. Vet Clin North Am Equine Pract 2021; 37:177-205. [PMID: 33820606 DOI: 10.1016/j.cveq.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Forage availability should cover most needs for mares bred during spring and summer. Out-of-season breeding, lack of access to pasture, or good quality forage calls for nutritional supplementation. Current evaluations of broodmare needs are based on fetoplacental tissue requirements, but do not consider endocrine changes or that the maternal diet quality affects long-term foal health. This article reviews pregnant mares' current nutritional recommendations. Secondly, fetoplacental developmental stages during gestation are outlined, defining critical periods in the context of the developmental origins of health and disease. Last, examples of how maternal nutrition affects long-term foal health are presented.
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Affiliation(s)
- Morgane Robles
- Institut National de la Recherche Scientifique (INRS), Centre Armand Frappier, 532 Boul. des Prairies, Laval, Quebec, Canada H7V 1B7; Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France.
| | - Carolyn Hammer
- Department of Animal Sciences, North Dakota State University, 1300 Albrecht Boulevard, Fargo, ND 58102, USA
| | - Burt Staniar
- Penn State University, 316 Agricultural Sciences & Industries Building, University Park, PA 16802, USA
| | - Pascale Chavatte-Palmer
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France
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Clothier J, Small A, Hinch G, Brown WY. Prematurity and Dysmaturity Are Associated With Reduced Height and Shorter Distal Limb Length in Horses. J Equine Vet Sci 2020; 91:103129. [PMID: 32684267 DOI: 10.1016/j.jevs.2020.103129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/26/2020] [Accepted: 05/11/2020] [Indexed: 12/17/2022]
Abstract
The long-term effects of gestational immaturity in the premature (defined as < 320 days gestation) and dysmature (normal term but showing some signs of prematurity) foal have not been thoroughly investigated. Studies have reported that a high percentage of gestationally immature foals with related orthopedic issues such as incomplete ossification may fail to fulfill their intended athletic purpose, particularly in Thoroughbred racing. In humans, premature birth is associated with shorter stature at maturity and variations in anatomical ratios, linked to alterations in metabolism and timing of physeal closure in the long bones. We hypothesized that gestational immaturity in horses might similarly be associated with reduced height and different anatomical ratios at maturity. In this preliminary study, the skeletal ratios of horses with a history of gestational immaturity, identified through veterinary and breeder records, were compared with those of unaffected, closely related horses (i.e., sire, dam, sibling). External measurements were taken from conformation photographs of cases (n = 19) and related horses (n = 28), and these were then combined into indices to evaluate and compare metric properties of conformation. A principal component analysis showed that the first two principal components account for 43.8% of the total conformational variation of the horses' external features, separating horses with a rectangular conformation (body length > height at the withers), from those that are more square (body length = height at the withers). Varimax rotation of PC1 and analysis of different gestational groups showed a significant effect of gestational immaturity (P = .001), with the premature group being more affected than the dysmature group (P = .009, P = .012). Mean values for the four dominant indices showed that these groups have significantly lower distal limb to body length relationships than controls. The observed differences suggest that gestational immaturity may affect anatomical ratios at maturity, which, in combination with orthopedic issues arising from incomplete ossification, may have a further impact on long-term athletic potential.
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Affiliation(s)
- Jane Clothier
- Agriculture and Food, CSIRO, New England Highway, Armidale, New South Wales, Australia; Canine and Equine Research Group, University of New England, Armidale, New South Wales, Australia; School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia.
| | - Alison Small
- Canine and Equine Research Group, University of New England, Armidale, New South Wales, Australia
| | - Geoff Hinch
- School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | - Wendy Y Brown
- Canine and Equine Research Group, University of New England, Armidale, New South Wales, Australia; School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
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Robles M, Couturier-Tarrade A, Derisoud E, Geeverding A, Dubois C, Dahirel M, Aioun J, Prezelin A, Calvez J, Richard C, Wimel L, Chavatte-Palmer P. Effects of dietary arginine supplementation in pregnant mares on maternal metabolism, placental structure and function and foal growth. Sci Rep 2019; 9:6461. [PMID: 31015538 PMCID: PMC6478728 DOI: 10.1038/s41598-019-42941-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/27/2019] [Indexed: 12/17/2022] Open
Abstract
Foals born to primiparous mares are lighter and less mature than those born to multiparous dams. Factors driving this difference are not totally understood. Using 7 multiparous and 6 primiparous standardbred mares, we demonstrated that, in late gestation, primiparous mares were less insulin resistant compared to multiparous mares, and that their foals had reduced plasma amino-acid concentrations at birth compared to foals born to multiparous mares. Vascular development, as observed through structure and gene expression, and global DNA methylation were also reduced in primiparous placentas. Another group of 8 primiparous mares was orally supplemented with L-arginine (100 g/day, 210d to term). L-arginine improved pregnancy-induced insulin resistance and increased maternal L-arginine and L-ornithine plasma concentrations but foal plasma amino acid concentrations were not affected at birth. At birth, foal weight and placental biometry, structure, ultra-structure and DNA methylation were not modified. Placental expression of genes involved in glucose and fatty acid transfers was increased. In conclusion, maternal insulin resistance in response to pregnancy and placental function are reduced in primiparous pregnancies. Late-gestation L-arginine supplementation may help primiparous mares to metabolically adapt to pregnancy and improve placental function. More work is needed to confirm these effects and ascertain optimal treatment conditions.
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Affiliation(s)
- Morgane Robles
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | | | - Emilie Derisoud
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Audrey Geeverding
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Cedric Dubois
- IFCE, Station Expérimentale de la Valade, 19370 Chamberet, France
| | - Michele Dahirel
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Josiane Aioun
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Audrey Prezelin
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Juliane Calvez
- UMR PNCA, AgroParisTech, INRA, Université Paris Saclay, 75005 Paris, France
| | - Christophe Richard
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - Laurence Wimel
- IFCE, Station Expérimentale de la Valade, 19370 Chamberet, France
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Jacobs RD, Ealy AD, Pennington PM, Pukazhenthi B, Warren LK, Wagner AL, Johnson AK, Hess TM, Knight JW, Splan RK. Dietary Supplementation of Algae-Derived Omega-3 Fatty Acids Influences Endometrial and Conceptus Transcript Profiles in Mares. J Equine Vet Sci 2018. [DOI: 10.1016/j.jevs.2017.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Robles M, Peugnet PM, Valentino SA, Dubois C, Dahirel M, Aubrière MC, Reigner F, Serteyn D, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P. Placental alterations in structure and function in intra-uterine growth-retarded horses. Equine Vet J 2017; 50:405-414. [DOI: 10.1111/evj.12761] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 09/21/2017] [Indexed: 01/01/2023]
Affiliation(s)
- M. Robles
- UMR, BDR, INRA, ENVA, Université Paris Saclay; Jouy en Josas France
| | - P. M. Peugnet
- UMR, BDR, INRA, ENVA, Université Paris Saclay; Jouy en Josas France
| | - S. A. Valentino
- UMR, BDR, INRA, ENVA, Université Paris Saclay; Jouy en Josas France
| | - C. Dubois
- IFCE, Station Expérimentale; Chamberet France
| | - M. Dahirel
- UMR, BDR, INRA, ENVA, Université Paris Saclay; Jouy en Josas France
| | - M.-C. Aubrière
- UMR, BDR, INRA, ENVA, Université Paris Saclay; Jouy en Josas France
| | | | - D. Serteyn
- Clinique équine; Faculté de Médecine Vétérinaire; CORD; Université de Liège; Liège Belgique
| | - L. Wimel
- IFCE, Station Expérimentale; Chamberet France
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Effects of season on placental, foetal and neonatal development in horses. Theriogenology 2017; 97:98-103. [PMID: 28583616 DOI: 10.1016/j.theriogenology.2017.04.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/30/2017] [Accepted: 04/19/2017] [Indexed: 12/24/2022]
Abstract
Seasonal changes in metabolic rate have been shown in horses and we hypothesized that this leads to the birth of smaller foals early in the year. Mares and their foals were assigned to three groups by day of foaling within the year (e.g. 1 January = day 1): Group 1 (n = 10) day 40-65, group 2 (n = 8) day 67-92, group 3 (n = 9) day 94-121. Groups did not differ with regard to parity. In foals, height at withers and body weight were determined on days 1-5 and weekly until 12 weeks of age. Chest circumference, distances fetlock to carpus, carpus to elbow, poll to nose and crown-rump length were determined on day 5 and weekly until 12 weeks of age. Placental weight (p < 0.05) and surface (p < 0.01) were lower in mares of group 1 than in groups 2 and 3. Foal weight and length measurements increased over time (p < 0.001). Height at withers was consistently lower in group 1 than in groups 2 and 3 (p < 0.05) while foal weight did not differ among groups. Fetlock to carpus, carpus to elbow (both p < 0.01) and poll to nose length (p < 0.05) were lower in group 1 than in groups 2 and 3. Neither gestation length nor sex ratio of foals differed among groups. In conclusion, foetal size is reduced when the final growth phase coincides with the winter months. This also impacts neonatal growth during the first three months of life.
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Maternal Nutrition during Pregnancy Affects Testicular and Bone Development, Glucose Metabolism and Response to Overnutrition in Weaned Horses Up to Two Years. PLoS One 2017; 12:e0169295. [PMID: 28081146 PMCID: PMC5231272 DOI: 10.1371/journal.pone.0169295] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/14/2016] [Indexed: 12/21/2022] Open
Abstract
Introduction Pregnant mares and post-weaning foals are often fed concentrates rich in soluble carbohydrates, together with forage. Recent studies suggest that the use of concentrates is linked to alterations of metabolism and the development of osteochondrosis in foals. The aim of this study was to determine if broodmare diet during gestation affects metabolism, osteoarticular status and growth of yearlings overfed from 20 to 24 months of age and/or sexual maturity in prepubertal colts. Material and methods Twenty-four saddlebred mares were fed forage only (n = 12, group F) or cracked barley and forage (n = 12, group B) from mid-gestation until foaling. Colts were gelded at 12 months of age. Between 20 and 24 months of age, all yearlings were overfed (+140% of requirements) using an automatic concentrate feeder. Offspring were monitored for growth between 6 and 24 months of age, glucose homeostasis was evaluated via modified frequently sampled intra veinous glucose tolerance test (FSIGT) at 19 and 24 months of age and osteoarticular status was investigated using radiographic examinations at 24 months of age. The structure and function of testicles from prepubertal colts were analyzed using stereology and RT-qPCR. Results Post-weaning weight growth was not different between groups. Testicular maturation was delayed in F colts compared to B colts at 12 months of age. From 19 months of age, the cannon bone was wider in B vs F yearlings. F yearlings were more insulin resistant at 19 months compared to B yearlings but B yearlings were affected more severely by overnutrition with reduced insulin sensitivity. The osteoarticular status at 24 months of age was not different between groups. Conclusion In conclusion, nutritional management of the pregnant broodmare and the growing foal may affect sexual maturity of colts and the metabolism of foals until 24 months of age. These effects may be deleterious for reproductive and sportive performances in older horses.
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Perinatal Diseases. Vet Med (Auckl) 2017. [PMCID: PMC7150149 DOI: 10.1016/b978-0-7020-5246-0.00019-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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Effects of birth weight, sex and neonatal glucocorticoid overexposure on glucose–insulin dynamics in young adult horses. J Dev Orig Health Dis 2016; 8:206-215. [DOI: 10.1017/s2040174416000696] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In several species, adult metabolic phenotype is influenced by the intrauterine environment, often in a sex-linked manner. In horses, there is also a window of susceptibility to programming immediately after birth but whether adult glucose–insulin dynamics are altered by neonatal conditions remains unknown. Thus, this study investigated the effects of birth weight, sex and neonatal glucocorticoid overexposure on glucose–insulin dynamics of young adult horses. For the first 5 days after birth, term foals were treated with saline as a control or ACTH to raise cortisol levels to those of stressed neonates. At 1 and 2 years of age, insulin secretion and sensitivity were measured by exogenous glucose administration and hyperinsulinaemic–euglycaemic clamp, respectively. Glucose-stimulated insulin secretion was less in males than females at both ages, although there were no sex-linked differences in glucose tolerance. Insulin sensitivity was greater in females than males at 1 year but not 2 years of age. Birth weight was inversely related to the area under the glucose curve and positively correlated to insulin sensitivity at 2 years but not 1 year of age. In contrast, neonatal glucocorticoid overexposure induced by adrenocorticotropic hormone (ACTH) treatment had no effect on whole body glucose tolerance, insulin secretion or insulin sensitivity at either age, although this treatment altered insulin receptor abundance in specific skeletal muscles of the 2-year-old horses. These findings show that glucose–insulin dynamics in young adult horses are sexually dimorphic and determined by a combination of genetic and environmental factors acting during early life.
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Jellyman JK, Valenzuela OA, Fowden AL. HORSE SPECIES SYMPOSIUM: Glucocorticoid programming of hypothalamic-pituitary-adrenal axis and metabolic function: Animal studies from mouse to horse1,2. J Anim Sci 2015; 93:3245-60. [DOI: 10.2527/jas.2014-8612] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J. K. Jellyman
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502
| | - O. A. Valenzuela
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - A. L. Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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Jellyman JK, Valenzuela OA, Allen VL, Forhead AJ, Holdstock NB, Fowden AL. Neonatal glucocorticoid overexposure programs pituitary-adrenal function in ponies. Domest Anim Endocrinol 2015; 50:45-9. [PMID: 25240233 DOI: 10.1016/j.domaniend.2014.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 06/18/2014] [Accepted: 06/22/2014] [Indexed: 01/18/2023]
Abstract
The present study tested the hypothesis that overexposure to endogenous glucocorticoids in neonatal life alters the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis in ponies at 1 and 2 yr of age. Newborn foals received saline (0.9% NaCl, n = 8, control) or long-acting adrenocorticotropic hormone (ACTH1-24) (Depot Synacthen 0.125 mg intramuscularly twice daily, n = 9) for 5 d after birth to raise cortisol concentrations 5- to 6-fold. At 1 and 2 yr of age, HPA axis function was assessed by bolus administration of short-acting ACTH1-24 (1 μg/kg intravenous) and insulin (0.5 U/kg intravenous) to induce hypoglycemic on separate days. Arterial blood samples were taken at 5 to 30-min intervals before and after drug administration to measure plasma ACTH and/or cortisol concentrations. There were no differences in the basal plasma ACTH or cortisol concentrations or in the cortisol response to exogenous ACTH1-24 with neonatal treatment or age. At 1 and 2 yr of age, the increment in plasma ACTH but not cortisol at 60 min in response to insulin-induced hypoglycemia was greater in ponies treated neonatally with ACTH than saline (P < 0.05). Neonatal cortisol overexposure induced by neonatal ACTH treatment, therefore, alters functioning of the HPA axis in adult ponies.
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Affiliation(s)
- J K Jellyman
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK.
| | - O A Valenzuela
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - V L Allen
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - A J Forhead
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - N B Holdstock
- Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - A L Fowden
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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