Plasma profile of pregnancy associated glycoprotein (PAG) in pregnant Alpine goats using two radioimmunoassay (RIA) systems

Effect of ambient lead on progesterone and pregnancy-associated glycoprotein 1 and their relationship with abortion in Zaraibi goats: a field study

This study aimed to investigate the impact of ambient lead (Pb) exposure on progesterone (P4) and pregnancy-associated glycoprotein 1 (PAG1) and their relationship with abortion in Egyptian Zaraibi goats (C. hircus). To achieve this, 40 female goats (does) were mated with highly fertile male goats, resulting in a total of 28 pregnant goats. Eight of them aborted, and each of the 12 pregnant goats gave birth to one kid, whereas the remaining eight gave birth to twins. The levels of PAG1, P4, and Pb in serum were estimated by enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and inductively coupled plasma mass spectrometry (ICP-MS) respectively. Statistically, the repeated measure two-way ANOVA, regression analysis, correlation coefficient, and receiver operating characteristic (ROC) curves were applied. The current data demonstrated that the levels of blood Pb in aborted goats were significantly higher than those in non-aborted goats at the early, mid, and late gestations, and this was followed by significant decreases in serum PAG1 and P4. Furthermore, there were substantial inverse associations between blood Pb concentration and levels of PAG1 and P4, with markedly negative correlation coefficients of - 0.88 and - 0.77, respectively, in aborted goats. The threshold level of Pb required to cause abortion was ≥ 32.08 μg/dl, but for PAG1 and P4 were respectively ≤ 0.95 ng/ml and ≤ 0.48 ng/ml. Additionally, threshold levels of ≥ 12.34 ng/ml and ≥ 31.52 ng/ml for P4 and PAG1, respectively, were needed to deliver twins. In conclusion, pollution-induced increases in Pb bioavailability resulted in dramatic decreases in P4 and PAG1 levels, leading to abortions. PAG1 and P4 levels are also key factors in determining whether Zaraibi goats will give birth to twins.

Using Pregnancy-Associated Glycoproteins (PAGs) to Improve Reproductive Management: From Dairy Cows to Other Dairy Livestock

Simple Summary

Pregnancy loss is a major cause of infertility in dairy animals, particularly in cattle, which affects the productivity and profitability of farms. Detecting these unsuccessful pregnancies could offer farmers the opportunity to reduce the economic damage caused by pregnancy loss. The determination of proteins secreted by the placenta and related to the presence of a viable conceptus called pregnancy-associated glycoproteins (PAGs) represents a diagnostic tool to identify pregnant or non-pregnant animals and to predict early pregnancy failures. This review describes the state of the art related to PAGs’ function, pregnancy profile, and use in reproductive management in bovine and other dairy livestock.

Abstract

Pregnancy success represents a major issue for the economic income of cattle breeders. Early detection of pregnant and non-pregnant animals, as well as the prediction of early pregnancy failure, can influence farm management decisions. Several diagnostic tools for pregnancy are currently available. Among these, pregnancy-associated glycoproteins (PAGs) have been shown to be useful for identifying the presence of vital embryos and for pregnancy follow-up monitoring. This review presents an overview of the PAGs’ functions, their pregnancy trends, and their use as a tool to improve reproductive management in bovine and other dairy livestock, such as small ruminants and buffalos.

Plasmatic Profile of Pregnancy-Associated Glycoprotein (PAG) during Gestation and Postpartum in Sarda and Lacaune Sheep Determined with Two Radioimmunoassay Systems

Simple Summary

Nowadays the need to optimize and maximize the productivity of dairy sheep leads farmers to plan lambing in specific periods in order to avoid economic loss due to nonproductive animals. The goal is to diagnose pregnancy at early gestation in order to minimize the costs of unproductive animals and to properly formulate rations for the energy requirements of gestating or lactating animals at the same time. Moreover, early pregnancy diagnosis, as well as the possibility of distinguishing between single and multiple gestations, enables farmers to plan the management of lambing well in advance thus minimizing manpower requirements. This study showed, for the first time, the plasmatic profile of PAG (pregnancy-associated glycoproteins) in Sarda and Lacaune ewes during gestation and the postpartum period using two different radioimmune assay (RIA) systems, thus enhancing our knowledge regarding PAG concentrations in domestic ruminants. Moreover, it showed that for both breeds these RIA systems are capable of distinguishing pregnant from nonpregnant ewes starting from day 18 of gestation. Furthermore, the rapid disappearance of PAG concentration following lambing did not require the use of a cut-off limit in postpartum animals as a means for detecting a new pregnancy.

Abstract

This study was carried out to determine ovine pregnancy-associated glycoprotein (oPAG) levels in the plasma of Sarda and Lacaune ewes throughout gestation and in the first month postpartum, using two heterologous radioimmunoassays (RIA-706 and RIA-srPool) and to study the correlations between PAG levels and fetal gender and number. On Day 18 of pregnancy, PAG concentrations were detected in 90.1% and 80.8% of Sarda pregnant ewes with RIA-706 and RIA-srPool, respectively; and in 90% and in 75% of Lacaune pregnant ewes with RIA-706 and RIA-srPool, respectively. From Day 30, PAG concentrations were detected in all pregnant ewes by using both RIA methods. In the postpartum period, the PAG concentrations in Sarda ewes decreased rapidly reaching minimal levels (<1 ng/mL) on day 28 using both RIA-706 and RIA-srPool. In Lacaune ewes, PAG-706 levels were higher than PAG-srPool from parturition until the last day of observation (Day 28 postpartum). It was also observed that mean concentrations were higher in multiple than in single pregnancies in Sarda and Lacaune ewes. Moreover, due to the rapid disappearance of PAG concentration following lambing, a cut-off limit in postpartum animals was not required as a means for detecting a new pregnancy.

Relationship of foetal number and parity in Barbari goats to plasma profile of caprine pregnancy-associated glycoprotein (caPAG) during gestation and the early postpartum period

This study was conducted to characterise pregnancy-associated glycoprotein (caPAG) in peripheral plasma during gestation and postpartum periods of nulliparous and multiparous does with one or two foetuses using a caPAG specific two-step sandwich ELISA system. Earliest time-points for detection of pregnancy and foetal number with appropriate cut-off values were identified. Plasma samples from 15 pregnant (multiparous: n = 8; nulliparous: n = 7; during pregnancy and postpartum period) and six non-pregnant (during oestrous cycle) goats were collected and analysed. Mean caPAG concentration was greater than the threshold for pregnancy detection (S-N = 0.40) on d22, peaked on d45 and remained unchanged until parturition. From d45 until parturition, caPAG concentration in multiparous does with two foetuses was 1.4 to 1.8 fold greater (P < 0.001) than those with one foetus. For the ELISA, 0.83 (S-N) was the most appropriate cut-off to differentiate does with two from those with a single foetus with an overall sensitivity and accuracy of 88.9% and 84.7%, respectively. Circulating caPAG concentration in multiparous goats was greater (P < 0.05) compared with nulliparous goats during the early pregnancy and postpartum periods. After parturition, caPAG concentrations markedly decreased and were basal within 14 days postpartum. In conclusion, using the caPAG specific ELISA, results indicated there were unique gestational and postpartum profiles for caPAG concentrations that are affected by number of foetuses and parity of the doe. The marked decrease in concentration of caPAG following parturition indicates there would not be compromising of the detection of subsequent pregnancies in goats using this technique.

Temporal changes in pregnancy-associated glycoproteins across different stages of gestation in the Barbari goat

The objective of this study was to characterize the temporal profile of pregnancy-associated glycoproteins (PAGs; isoforms 1-11) across different stages of gestation in the Barbari goat. Placentae were collected from local abattoir, classified according to crown rump length of the corresponding foetus into five groups (0-30, 31-60, 61-90, 91-120, and 121-150 days of gestation), and used for relative quantification of mRNA expression by Pfaffl method. In addition, adult female goats (pregnant, n = 7; non-pregnant, n = 5) were used to estimate weekly plasma PAG and progesterone (P4) concentrations. The relative mRNA expression of PAGs was greater (p<0.05) during 31-60 days of gestation, which correlated well with the temporal changes in plasma PAG concentrations. Relative expression of PAGs decreased steadily as gestation advanced with minimum expression observed just before parturition, except for PAG-4 and PAG-8 that showed constantly higher expression throughout pregnancy. Plasma PAG and P4 concentrations showed a distinct temporal pattern with a significant increase beginning at 2 weeks and return to basal levels by 20 weeks of gestation. However, PAG concentrations reached a peak earlier in gestation (8 weeks) than P4 (10-14 weeks). Correlation analysis indicated a strong positive association (r = 0.748, p<0.01) between plasma PAG and P4 concentrations. In conclusion, results of this study indicate a distinct temporal pattern of PAG expression and secretion during gestation in the Barbari goat. The temporal changes in PAGs and the positive association with P4 are suggestive of their role in maintenance of pregnancy and progressive foetal development.

Ultrasonography in early pregnancy diagnosis and measurements of fetal size in reindeer (Rangifer tarandus tarandus)

Transrectal or transabdominal examinations of 13 pluriparous reindeer (Rangifer tarandus tarandus) by ultrasonography from the start of mating until week 20 of gestation were conducted to find out when pregnancy could first be detected and to describe fetal development in early pregnancy. The examinations (n=35 per animal) were performed with a 5 MHz linear transducer from 7th October until 1st January and with a 3 MHz sector transducer from that time until 24th February. Time of pregnancy diagnosis by ultrasonography, the first fetal heartbeat and measurements of crown-rump length, chest width and chest depth were recorded during the examinations. Pregnancy was diagnosed by transrectal ultrasonography between the weeks 3 and 7 of gestation. The accuracy of the pregnancy diagnosis, defined as the proportion of females correctly detected to be pregnant, was 15% at week 3, 46% at week 4, 77% at week 5, and 92% at week 6 of gestation. Fetal heartbeat was first detected between the weeks 5 and 8 of gestation. The first measurements of crown-rump length were made on week 3 of gestation, of chest width on week 4 and of chest depth on week 5 of gestation. Chest width and depth were detectable until the end of the study at week 20 of gestation. Transrectal ultrasonography is an efficient tool in early pregnancy diagnosis of reindeer. The fetal growth curves obtained by ultrasonography resembled those obtained in previous morphological studies.