[Dynamics of morphophysiological characteristics in female water voles (Arvicola amphibius L.) during pregnancy].

Pregnancy and lactation need increased energy consumption and are accompanied by morphological and physiological changes of various maternal organs and systems. In water voles, connection of female interior characteristics has been poorly studied. Under standard vivarium conditions, we evaluated morphophysiological parameters of non-reproducing females and of females at the early (1-7 days), intermediate (8-14 days), and late (15-21 days) stages of pregnancy. There were established effect of the reproductive state on mass of abdominal and brown fat, liver, adrenals, spleen and an increment of body mass (without uterus with embryos). In pregnant females, as compared with the non-pregnant ones, the blood thyroxin level was significantly lower (16.2 +/- 0.8 and 21.7 +/- 1.4 pmpl/l) and the blood testosterone level was higher (1.29 +/- 0.19 and 0.83 +/- 0.09 nmol/l). The blood glucose content fell in the end of pregnancy. Dynamics of morphophysiological parameters at the period of pregnancy reflects the compensatory body reactions providing preservation of embryos and preparation to breeding of offspring.

[Protein content in urine of male and female water vole (Arvicola amphibious) at the period of spring growth and sexual maturation].

The study was carried out on the captive bread water voles Arvicola amphibious kept in vivarium. At the first decade of January, March, and June, the body length and anogenital distance were measured, the body mass was determined, and urine was collected for determination of its protein content. The obtained results have shown that the protein content depends on sex of the animals and is connected with the reproductive status of males and their dimension-weight characteristics. The urinary protein excretion level in females remained stable at different months, whereas in males its sharp rise was noted at the period of spring growth and sexual maturation. The significant sexual differences were established in March and enhanced in June. In March the urine protein content in males was noted to correlate positively with the body mass and length and with the anogenital distance. The males reached sexual maturity at the earlier calendar terms than the females did; in sexually mature males the urine protein content was significantly higher than in the sexually immature ones.

[Correlation between urine malondialdehyde level and males reproductive success in the water vole (Arvicola terrestris L.)].

The study was conducted in water vole (Arvicola terrestris L.) reared and bred in captivity. During the breeding season, voles were caged in heterosexual pairs for two weeks. If mating did not occur, new pairs were formed with unfamiliar partners. In the end of the breeding season, the individual male's reproductive characteristics were summarized, and the level of malondialdehyde (MDA) in their urine was assessed. As indicated by urine MDA concentration, the intensity of lipid peroxidation in males which could not became fathers was significantly higher than in fertile males. In the last group, the negative correlation between average numbers of pups in litter and urine MDA concentration was revealed. It is possible, that a causal factor of water vole males lowered fertility is oxidative stress.