The aim of this study was to evaluate the effect of feed restriction followed by a realimentation with monensin supplementation on morphological, ultrastructural, and apoptotic characteristics in the term placenta of Anglo-Nubian does. Treatments were a control group (C = 5), a group fed at 0.70 of that consumed by controls (R = 7), and the same as R with monensin (M = 7). After parturition, 27 placentas were gathered, C: 7, M: 10, and R: 10. No differences were detected between treatments in relation to morphological and ultrastructural analysis. The greatest values of binucleate cells were detected in placentas from R, and it could be due to the need to compensate and satisfy nutritional differences of restriction. We detected the highest apoptotic index in R as a consequence of nutritional treatment. We describe for the first time the structural and ultrastructural morphology and remodeling by apoptosis of Anglo-Nubian placenta at term of goats subjected to nutritional restriction during peripubertal period and the use of monensin as a growth promoter.

The placenta is a highly vascularized organ, indispensable tothe transfer of nutrients to the growing fetuses. During gestation, there exists an expansion of the placental vascular network through active angiogenesis. The aim of this research was to study cell proliferation and apoptosis through high resolution light microscopy (HRLM) and transmission electron microscopy (TEM) ultrastructure, immunohistochemistry for Ki67and caspase-3, determination of placental vascular area,and TUNEL assay. Crossbred sows placental tissues from approximately 30±2(n=5), 40±2(n=5), 60±2 (n=5), 80±2(n=5), 90±2(n=5) and 114±2(n=5) days of gestation were used. The evaluation of cell proliferation showed the highest%Ki67 values on days 30±2 and 80±2 of pregnancy. Caspase-3 expressed the highest value on day 30±2, while the highest apoptotic indexes were found on days30±2 and 90±2. The placental vascular area was higher on day 80±2 of pregnancy. According to our results, an active vascular cell remodeling by a caspase-3 dependent apoptosis seems to be present in early pregnancy. The increase in the vascular area on day 80±2 would be the result of the intense vascular cell proliferation detected with Ki67. Further studies are needed to understand the complex processes of angiogenesis, cell proliferation and apoptosis that interact in the placenta during porcine gestation.

The early development in mammals is characterized by the contribution of nutrients from the maternal tissues through the placenta, which is in apposition with foetal membranes and the endometrium, allowing the physiological interchange between the embryos/foetuses and the mother. The aim of this work was to study the number of placental blood vessels and their vascular area through morphometric analyses and the haemotrophic diffusion distance in porcine placental tissues from early gestations, intermediates gestations, advanced gestations and term gestations. For those purposes, morphometric measurements, blood vessel quantification, high-resolution light microscopy and transmission electron microscopy were performed. The implementation of the high-resolution light microscopy allowed studying the placental vascular and tissue histoarchitecture with higher definition and resolution than using a conventional light microscopy. We highlight the close location of the subepithelial capillaries to the maternal/foetal interface as pregnancy progresses. We found statistically significant evidence to state that the area of blood vessels is dependent on the gestation period. In advanced gestations, the presence of numerous small blood vessels and its near location to foetal/maternal interface agree with the great remodelling reported in our previous studies. In conclusion, in gilts, given the type of non-invasive epithelial placentation, the new blood vessels generation and of haemotrophic diffusion distance reduction, determined in this report, assure the maternal/foetal haemotrophic exchange efficiency during gestation.

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