Supplementation with rumen-protected L-arginine-HCl increased fertility in sheep with synchronized estrus

• Published in: Tropical animal health and production Vol. 47; no. 6; pp. 1067 - 1073
• Main Authors: Ruiz de Chávez, Julio Agustín, Guzmán, Adrian, Zamora-Gutiérrez, Diana, Mendoza, Germán David, Melgoza, Luz María, Montes, Sergio, Rosales-Torres, Ana María
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2015; Springer Nature B.V
• Subjects: Animals; Arginine - administration & dosage; Arginine - pharmacology; Biomedical and Life Sciences; Body weight; Dietary Supplements; Estrus - drug effects; Estrus Synchronization; Female; Fertility; Fertility - drug effects; Life Sciences; Ovulation - drug effects; Pasture; Pregnancy; Regular Articles; Reproduction - drug effects; Rumen - metabolism; Sheep; Veterinary Medicine/Veterinary Science; Zoology; Ewe; L-arginine-HCl; Estrus synchronization; VEGF
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-015-0833-4

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.