title: Supplementation with rumen-protected L-arginine-HCl increased fertility in sheep with synchronized estrus.
abstract: The aim of the present study was to evaluate the effects of L-arginine-HCl supplementation on ovulation rate, fertility, prolificacy, and serum VEGF concentrations in ewes with synchronized oestrus. Thirty Suffolk ewes with a mean body weight of 45 ± 3 kg and a mean body condition score (BCS) of 2.4 ± 0.28 were synchronized for estrus presentation with a progestin-containing sponge (20 mg Chronogest® CR) for 9 days plus PGF2-α (Lutalyse; Pfizer, USA) on day 7 after the insertion of the sponge. The ewes were divided into two groups; i.e., a control group (n = 15) that was fed on the native pasture (basal diet) and an L-arginine-HCl group (n = 15) that received 7.8 g of rumen-protected L-arginine-HCl from day 5 of the sponge insertion until day 25 after mating plus the basal diet. The L-arginine-HCl was administered daily via an esophageal probe between days 5 and 9 of the synchronization protocol and every third day subsequently. Blood samples were drawn from the jugular vein every 6 days throughout the entire experimental period. The results revealed that the L-arginine-HCl supplementation increased fertility during the synchronized estrus (P = 0.05). However, no effects were observed on the final BCS (P = 0.78), estrus presentation (P = 0.33), multiple ovulations (P = 0.24), prolificacy (P = 0.63), or serum VEGF concentration. In conclusion, L-arginine-HCl supplementation during the period used in this study increased fertility in sheep with synchronized estrus possibly due to improved embryo-fetal survival during early pregnancy.
authors.affiliation: Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Col. Villa Quietud, Coyoacán, 04960, México, DF, Mexico.
authors.forename: Julio Agustín Ruiz
authors.initials: JA
authors.lastname: de Chávez
authors.forename: Adrian
authors.initials: A
authors.lastname: Guzmán
authors.forename: Diana
authors.initials: D
authors.lastname: Zamora-Gutiérrez
authors.forename: Germán David
authors.initials: GD
authors.lastname: Mendoza
authors.forename: Luz María
authors.initials: LM
authors.lastname: Melgoza
authors.forename: Sergio
authors.initials: S
authors.lastname: Montes
authors.forename: Ana María
authors.initials: AM
authors.lastname: Rosales-Torres
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004971:Estrus / Q000187:drug effects; D004973:Estrus Synchronization; D005260:Female; D005298:Fertility / Q000187:drug effects*; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy; D012098:Reproduction / Q000187:drug effects; D012417:Rumen / Q000378:metabolism*; D012756:Sheep
chemical_list: D001120:Arginine