Seasonal luteal cyclicity of pubertal and adult red deer (Cervus elaphus)

Haematological and chosen biochemical parameter assessment of the antioxidant system in red deer (Cervus elaphus) blood in early and late pregnancy

Introduction

The aim of this study was to investigate changes in haematological parameters and the antioxidant system in the early and late pregnancy of red deer (Cervus elaphus).

Material and Methods

Blood samples were collected from 30 red deer females 50 days after impregnation and 40 days before calving. Complete blood counts and stained blood smears were assessed. Paraoxonase 1 (PON1), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) activities, glutathione disulphide (GSSG), total glutathione, total bilirubin, total protein, albumin, uric acid, malondialdehyde (MDA), beta-hydroxybutyrate (BHB), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, cholesterol levels and total antioxidant status (TAS) were measured.

Results

The haematological characteristics of blood collected in the third trimester showed higher haemoglobin levels, haematocrit, mean corpuscular volume (P < 0.05) and a lower mean cell haemoglobin concentration (P < 0.05) in comparison to samples collected on the 50^th day after mating. Activity of CAT and MDA, LDL, and triglyceride levels were lower while GR, GSSG, total glutathione, total protein and BHB levels were increased in blood samples drawn in the third trimester compared with the first trimester blood samples. There were no changes in SOD, PON1 activities, TAS, bilirubin, albumin, HDL, cholesterol or uric acid concentrations.

Conclusion

Red deer’s compensatory mechanisms facilitate its optimal adaptation to seasonal changes evidenced by mild pronounced haematological disturbances and an effective antioxidant system during pregnancy.

Artificial Reproductive Technology (ART) Applied to Female Cervids Adapted from Domestic Ruminants

There are about 150 Cervidae species on the IUCN Red List of Threatened Species. Only a small part is counted among farm animals, and most of them are free roaming. The universality and large numbers of representatives of cervids such as red deer (Cervus elaphus) and roe deer (Capreolus capreolus) may predispose these species to be used as models for research on reintroduction or assisted reproduction of deer at risk of extinction. We outlined the historical fluctuation of cervids in Europe and the process of domestication, which led to breeding management. Consequently, the reproductive techniques used in domestic ruminants were adapted for use in female deer which we reviewed based on our results and other available results. We focused on stress susceptibility in cervids depending on habitat and antropopression and proposed copeptin as a novel diagnostic parameter suitable for stress determination. Some reproductive biotechniques have been adopted for female cervids with satisfactory results, e.g., in vitro fertilization, while others still require methodological refinement, e.g., cryopreservation of oocytes and embryos.

Production of prostaglandins in placentae and corpus luteum in pregnant hinds of red deer (Cervus elaphus)

Prostaglandins (PGs) are synthesized from arachidonic acid by prostaglandin synthase 2 (PTGS2) and specific terminal PG synthases such as PGES and PGFS. The role of PGs in the reproductive processes of domestic ruminants is well recognized, whereas in cervidae, it is almost unknown, although it is noteworthy because some species of this family are valued in meat production and trophies. The aim of this study was to determine an effective marker of pregnancy and investigate the production and secretion of PGs in placenta and CL tissue in pregnancy. In the preliminary experiment, the levels of progesterone and 17-β estradiol (RIA; N = 14 divided into seven pregnant and seven nonpregnant hinds) were measured in the peripheral blood. In the main experiment, a comparison of messenger RNA (real-time polymerase chain reaction) and protein expression (Western blotting) of PTGS2, PGES, and PGFS, the level of prostaglandin E2 (PGE2) and PGF2α in the placentae and CL in pregnant hinds (aged 3-4 years, ca. 100 days of pregnancy, N = 6). In pregnant hinds, the level of progesterone in the blood was higher than that in nonpregnant hinds (P < 0.05), whereas the level of E2 was similar in all animals (P > 0.05). The highest messenger RNA expression of PTGS2, PGES, and PGFS was observed in the placentae than in the CL (P < 0.05). The protein expression of PTGS2 and PGES was elevated in the placentae compared with the CL (P < 0.05). The PGE2 output was the highest in cotyledonary tissue (P < 0.05). Pregnancy development in hinds around 100 days is regulated by arachidonic acid metabolites, especially PGE2 produced by the placentae, which production increases in pregnancy. Further studies are required to unravel the mechanisms involved in the regulation of PG and biosynthetic enzymes in uteroplacental and ovarian tissues during pregnancy in red deer females.

Plasma progesterone changes and length of oestrous cycle in Rusa Deer (Rusa timorensis)

A study was conducted to profile the plasma progesterone (P4) concentrations and establish the length of oestrous cycle in the Rusa timorensis during the breeding season. Five healthy hinds were selected for peripheral blood sampling twice weekly to gauge the P4 levels by radioimmunoassay, at the start of the breeding season indicated by rutting behaviours of sexually active males. The hinds were polyestrous as proven by the cyclic trend of P4 levels. After the presumptive oestrus indicated by the lowest P4 concentrations (0.20±0.09ng/ml), this ovarian hormone was markedly elevated on day 7 of the cycle (0.78±0.20ng/ml), reached its peak (2.61±0.23ng/ml, P<0.05) on day 14, and then declined to the basal level in the subsequent oestrus. The mean oestrous cycle length in R. timorensis during the breeding season was 19.2 days with a range of 18-21 days, and the pattern of circulating progesterone during the oestrous cycle of the R. timorensis is similar to those of other deer species. It was also observed that the length of oestrous cycle of R. timorensis determined by gauging the progesterone levels and observation of the oestrous behaviours as well as changes in the cellular pattern of vaginal epithelial cells are highly consistent.