Investigation of mechanisms involved in regulation of progesterone catabolism using an overfed versus underfed ewe-lamb model

Placental Malfunction, Fetal Survival and Development Caused by Sow Metabolic Disorder: The Impact of Maternal Oxidative Stress

The energy and metabolic state of sows will alter considerably over different phases of gestation. Maternal metabolism increases dramatically, particularly in late pregnancy. This is accompanied by the development of an increase in oxidative stress, which has a considerable negative effect on the maternal and the placenta. As the only link between the maternal and the fetus, the placenta is critical for the maternal to deliver nutrients to the fetus and for the fetus' survival and development. This review aimed to clarify the changes in energy and metabolism in sows during different pregnancy periods, as well as the impact of maternal oxidative stress on the placenta, which affects the fetus' survival and development.

Feeding Tall Fescue Seed during Mid and Late Gestation Influences Subsequent Postnatal Growth, Puberty, and Carcass Quality of Offspring

Weaned lambs (n = 82), born to ewes fed endophyte-free (E-) or endophyte-infected (E+; 1.77 mg hd-1 d-1 ergovaline + ergovalinine) tall fescue seed from d 35 to 85 of gestation (MID) and/or d 86 of gestation to parturition (LATE), were used to examine how ergot alkaloid exposure during fetal development altered subsequent puberty attainment or carcass quality. Lambs were weaned at 75 d of age and separated by sex to assess puberty in ewe lambs (n = 39) and to evaluate growth, carcass and meat quality in wethers (n = 43). Data were analyzed with maternal fescue treatment, stage of gestation, and two-way interaction in the model. Age at puberty tended (P = 0.06) to be longer for ewe lambs born to dams fed E+ fescue during LATE gestation versus those fed E-. Post-weaning average daily gain tended to be higher (P = 0.07) for wether lambs born to dams fed E+ fescue seed during MID gestation compared to E-. Exposure to ergot alkaloids during fetal growth altered (P < 0.10) longissimus muscle weight and color, lipid deposition, fatty acid composition, and shear force values of semimembranosus muscle in wether lambs. These results indicate that exposure to ergot alkaloids in utero does alter subsequent post-weaning puberty attainment and body composition in offspring.

Effects of post-insemination energy content of feed on embryonic survival in pigs: A systematic review

The feeding of diets with greater energy content than that needed for body maintenance following mating is believed to reduce embryonic survival in pigs. In swine operations, therefore, feed intake is often restricted during the first and second week of pregnancy to reduce embryo mortality. There is thought to be a relationship between feeding diets that result in energy intake that is greater than that needed for body maintenance and embryonic death. This relationship is associated with lesser than typical progesterone (P4) concentrations when feeding diets with greater energy content due to increased hepatic clearance. There is no consensus, however, as to whether feeding should be restricted during early pregnancy to avert this possible detrimental effect. Thus, the aim of this systematic review is to assess the effect in sows and gilts of feeding diets with different energy contents post-mating on embryonic survival, evaluating when possible, the relationship of a greater energy intake and P4 concentrations on embryonic survival. An electronic search was conducted of the PubMed, Science Direct, Scopus, Web of science, and Scielo databases during June 2018. A total of 109 articles were retrieved, and of these, only 16 articles were selected after applying the selection criteria. There was no negative effect of a greater feed intake than that needed for body maintenance after breeding in 75% of the experiments. Results from 35% of the experiments indicated feeding early pregnant sows a diet with greater energy content than that needed for body maintenance resulted in augmented embryonic death. In 66.7% of the experiments, in which there was assessment of P4 concentration, there was no negative effect of feeding after farrowing a diet with greater energy than that needed for body maintenance. In conclusion, it appears that restricted feed intake in early pregnancy is no longer relevant when there are modern prolific dam lines utilized in swine production enterprises because dietary energy of as great as 54 MJ ME/day had no detrimental effect on embryo survival.