Creatine-precursor exposure in ewe twin pregnancy directs metabolic effort and reworks the maternal-fetal vascular system, involving genetic markers that modulate the creatine pathway.

Although creatine has a recognized role during gestation, there is still little information about multiple pregnancies. Especially in small ruminants, these pregnancies increase nutritional needs and the incidence of pre- and postpartum metabolic or reproductive pathologies. Thus, the main objective of this study was to address this gap by providing information on the impact of dietary supplementation with the creatine precursor guanidinoacetic acid (GAA) on the maternal-fetal response during late gestation in twin-bearing ewes. A total of 15 twin-bearing ewes were allocated to a baseline total mixed ration (TMR) diet group (BSTMR, n = 8) or a group whose TMR was supplemented daily with 0.9 g/kg of a diabetes mellitus (DM) diet of guanidinoacetic acid TMR (GATMR, n = 7) from 100 days of gestation until lambing. The GATMR ewes adapted their diet selectivity and exhibited a smaller reduction in loin and kidney fat thickness. GAA supply increased peripheral levels of albumin, globulin, glucose, and cholesterol. In the GATMR group, a reduced development of the uterine artery, umbilical vascular system, caruncle thickness, and fetal heart rate was observed. Cotyledonary capillary structure in GATMR showed slower growth and sub-expression of FGF2 and FLT1, whereas the antiangiogenic factor ODC1 had a higher expression. The GATMR group also exhibited lower expression of the creatine regulator GAMT and a higher expression of the creatine kinase CKM gene. Thus, the evidence indicates that GAA is effective in twin pregnancies even when provided in a rumen-unprotected form. The results also highlight the need for further studies to better modulate the dosage, adapting it to the demands of pregnancy.