Supplemental progesterone during early pregnancy exerts divergent responses on embryonic characteristics in sows and gilts
Bruno Bracco Donatelli Muro, Rafaella Fernandes Carnevale, Diego Feitosa Leal, M.A. Torres, Maitê Vidal Mendonça, Denis Hideki Nakasone, Cristian Hernando Garcia Martinez, Gisele Mouro Ravagnani, Matheus Saliba Monteiro, André Pegoraro Poor, Simone Maria Massami Kitamura Martins, P. Viau, Cláudio Alvarenga de Oliveira, Lidia Hildebrand Pulz, Ricardo de Francisco Strefezzi, Glen W. Almond, André Furugen Cesar de Andrade
Abstract
Progesterone (P4) plays a key role in pregnancy establishment and maintenance; during early pregnancy, P4 stimulates the production and release of uterine secretions necessary for conceptus growth prior to implantation; therefore, exogenous P4 supplementation may improve embryo development. This study evaluated the effects of supplementation during early pregnancy with long-acting injectable progesterone or altrenogest on embryonic characteristics of sows and gilts. Thus, a total of 32 sows and 16 gilts were used. On day 6 of pregnancy sows and gilts were allocated to one of the following groups: non-supplemented; supplemented with 20 mg of altrenogest, orally, from days 6 to 12 of pregnancy; supplemented with 2.15 mg/kg of long-acting injectable progesterone on day 6 of pregnancy. Animals were killed on day 28 of pregnancy, and ovulation rate, embryo survival, embryo weight, crown-to-rump length, uterine glandular epithelium and endometrial vascularization were assessed. Treatments had no effect on pregnancy rate, embryo survival or endometrial vascular density (P > 0.05). Non-supplemented gilts presented larger and heavier embryos compared to gilts from supplemented groups (P < 0.05). Sows in the altrenogest group presented larger and heavier embryos compared to non-supplemented sows and sows supplemented with long-acting injectable progesterone. In conclusion, supplementation of sows and gilts with progestagen from day 6 of pregnancy can be used as a means to improve embryo survival without deleterious effects.