title: Oral L-arginine supplementation impacts several reproductive parameters during the postpartum period in mares.
abstract: L-arginine is an amino acid which can alter pituitary function and increase blood flow to the reproductive tract. The objective was to determine the effect of supplementing 100g of L-arginine on plasma arginine concentrations, follicular dynamics and ovarian and uterine artery blood flow during the estrus that occurs subsequent to foaling. In Experiment 1, mares were fed 100g L-arginine for 1 day during the last 3 weeks of pregnancy and plasma samples taken for every hour for the first 4h and every other hour until 12h.L-arginine supplementation elevated plasma arginine concentrations from 1 to 8h post feeding; arginine peaked at 6h (arginine: 515±33μmol/L; control: 80±33μmol/L). In Experiment 2, mares received either 100g L-arginine or control diets beginning 21 d before the expected foaling date and continued for 30 d postpartum. The reproductive tract was evaluated by transrectal Doppler ultrasonography from Day 1 postpartum through Day 30. There were no differences in ovarian follicular dynamics, ovarian or uterine resistance indices between groups. Vascular perfusion of the F1 follicular wall was greater in L-arginine supplemented mares (37.3±2.6%) than controls (25.4±2.7%; P<0.05). L-arginine supplemented mares had a smaller uterine body and horns and accumulated less uterine fluid than controls (P<0.05). The combination of reducing uterine fluid accumulation, while not altering follicular development, raises the possible use of L-arginine supplementation as a breeding management tool during the postpartum period to increase reproductive success.
authors.affiliation: Department of Animal Sciences, University of Florida, 2250 Shealy Drive, Gainesville, FL 32608, USA.
authors.forename: Dale E
authors.initials: DE
authors.lastname: Kelley
authors.forename: Lori K
authors.initials: LK
authors.lastname: Warren
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Mortensen
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage* / Q000097:blood; D019587:Dietary Supplements; D004334:Drug Administration Schedule; D005260:Female; D006736:Horses / Q000502:physiology; D010053:Ovary / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D010060:Ovulation / Q000187:drug effects / Q000502:physiology; D049590:Postpartum Period / Q000187:drug effects* / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects*; D014463:Ultrasonography; D014599:Uterus / Q000098:blood supply / Q000187:drug effects / Q000502:physiology
chemical_list: D001120:Arginine