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Prenatal mortality is a major limitation for litter size; moreover, most of the losses occur in the first third of gestation. Maternal nutrition is one of the main factors affecting survival, growth, and development of embryos. Therefore, based on the hypothesis that L-arginine supplementation could produce changes in prenatal survival rates and conceptus development, the aim of the present study was to assess the effects of dietary 1% L-arginine supplementation on commercial gilts and the development of their embryos. For that purpose, 23 commercial gilts were hormonally synchronized after fourth estrus and inseminated in 2 periods, 12 and 24h after the beginning of estrus. Gilts were fed either a control diet (CON, n = 11), mainly composed of corn and soybean meal, or the CON diet supplemented with 1.0% ARG (ARG, n = 12), beginning 24h after the second insemination. At 25 and 35 days of gestation, five females from each treatment were slaughtered. Blood samples were taken and female phenotypic traits were measured. Conceptus (embryos: 25 days and fetuses: 35 days) were quickly collected and phenotypic data and gene expression analyses were performed. As a result, at day 25, insulin-like growth factor 1 (IGF1) gene was upregulated in ARG embryos. At this same gestational age, ARG embryos tended to be heavier compared to CON, and ARG gilts tended to have a greater arginine concentration in blood plasma. However, at day 35 of gestation, arginine concentration in blood plasma of ARG gilts tended to be lower compared to CON, and ARG fetuses showed smaller cephalic-caudal length. It could be concluded that the increased arginine concentration in plasma of females from ARG group and the increased IGF1 gene expression in ARG 25-day embryos were related to a tendency of higher embryo weight. However, supplementation for a longer period did not lead to changes in the expression of developmental genes in 35-days fetuses, although it decreased fetuses’ cephalic-caudal length, which may influence phenotypic traits as litter uniformity at birth. Therefore, supplementation duration is determinant for the effects that L-arginine exerts on the concentration of this amino acid in the plasma of gilts and on conceptuses growth.
Costa, K. A., Saraiva, A., Guimarães, J. D., Marques, D. B. D., Machado-Neves, M., Barbosa, L. M. R., Castaño-Villadiego F.A, Veroneze, R., Oliveira, L.F., Soares- Garcia, I., Teixeira, S.A. and Facioni-Guimarães, S.E. (2019). Dietary L-arginine supplementation during early gestation of gilts affects conceptuses development. Theriogenology, 140, 62-71. https://doi.org/10.1016/j.theriogenology.2019.08.018