Genetic parameters for bull effects on in vitro embryo production (IVP) and relationship between semen quality traits and IVP performance.

In vitro production of embryos (IVP) is increasingly applied in dairy cattle breeding and promises widespread use of females of superior genetic merits. One of the current challenges with implementation of IVP is the variability in blastocyst rates. Several factors contribute to these variabilities, among which is known to be the bull used for oocytes fertilization. The extent of genetic control of bulls' effect on IVP performances is yet to be investigated. This study estimates genetic parameters for bull effects on IVP performance traits including blastocyst rate, hatching rate and an index trait combining Blastocyst rate, Kinetic Score, and Morphology score (BL_M_K). The IVP experiments were performed using oocytes aspirated from slaughterhouse ovaries from Holstein cows, fertilized with semen from 123 Holstein bulls. A total of 77 in vitro fertilization (IVF) experiments with 163 records (different IVF groups) were available for the analysis. The results indicate low to moderate heritability and moderate to high repeatability estimates for bull effects on IVP performance traits. Our study also showed that some semen quality traits had significant effects on IVP performance. This included strong genetic correlations between pre-cryopreservation sperm viability and blastocyst rate as well as BL_M_K score at days 7 and 8. Despite the generally weak bull effect correlations and the high standard errors of the estimates, our results provide initial evidence of a measurable genetic component in the bull's impact on IVP performance traits. However, the high standard errors underscore the need for further studies with a larger sample size.

Nitrogen and phosphorus variation in shallow groundwater and assimilation in plants in complex riparian buffer zones.

The study of purification efficiency and nutrient assimilation in plants was made in two riparian buffer zones with a complex of wet meadow and grey alder (Alnus incana) stand. In the less polluted Porijõgi test site, the 31 m wide buffer zone removed 40% of total nitrogen (total-N) and 78% of total phosphorus (total-P), while a heavily polluted 51 m wide buffer zone in Viiratsi retained 85% of total-N and 84% of total-P. The input of nutrients and purification efficiency displayed a significant relationship. The total-N removal in buffer zone was negative when the input value was less than 0.3 mg l(-1) and the purification efficiency was always positive when the input value exceeded 5 mg l(-1). The purification efficiency of total-P was positive when the input value exceeded 0.15 mg l(-1). Grass vegetation plays an important role in nutrient retention in riparian buffer strips. The maximum phytomass production was measured in Porijõgi site where production of the Filipendula ulmaria community was up to 2,358 g m(-2), assimilation of N 32.1 and of P 4.9 g m(-2), respectively. This is much higher than the biomass production and N and P uptake of the grey alders (Alnus incana) at the same site--1,730, 20.5 and 1.5 g m(-2), respectively.

Energy metabolism and thyroid function of mice with deleted wolframin (Wfs1) gene.

There is no data about the energy metabolism of patients with Wolfram syndrome caused by mutations in the wolframin (Wfs1) gene. The aim of this study was to investigate the role of Wfs1 in energy metabolism and thyroid function in Wfs1 deficient mice (Wfs1KO). 16 male (8 Wfs1KO, 8 wild type (wt)) and 16 female (8 Wfs1KO, 8wt) mice aged 11-13 weeks were studied alone in a specific metabolic cage for 48 h. Body weight, food, water and O2 consumption, motor activity, CO2 and heat production of mice were recorded. At the age of 14-20 weeks, plasma levels of thyroxine (T4), TSH and leptin were measured and histology of thyroid tissues examined. Mean CO2 and heat production was not different between the groups. Mean O2 consumption was higher in the Wfs1KO females compared to the Wfs1KO males (3 410.0±127.0 vs. 2 806.0±82.4 ml/kg/h; p<0.05), but not compared to the wt mice. The mean movement activity was not different between the groups except that the Wfs1KO females reared up more often than the wt females (199.8±63.46 vs. 39.26±24.71 cnts/48 h; p<0.05). Both male and female Wfs1KO mice had significantly lower body mass and food intake than wt mice. Male Wfs1KO mice also lost more weight in metabolic cage than wt males (20.43±0.41 vs. 16.07±0.86%; p<0.05) indicating more pronounced response to isolation. Male Wfs1KO mice had significantly lower levels of plasma leptin than wt male mice (3.37±0.40 vs. 5.82±0.71 ng/ml; p<0.01). Thyroid function measured by serum TSH and T4 levels was not different between Wfs1KO and wt groups, but both Wfs1KO and wt male mice had significantly higher mean T4 levels than female mice. The histology of thyroid tissue of Wfs1KO males showed a trend to a smaller mean number of epithelial cells per follicle than the wt male mice.Although Wfs1KO mice were smaller and lost more weight during the experiment, their energy metabolism was not different from wt mice except that the female Wfs1KO mice consumed more O2. As mice in this study were relatively young, longitudinal studies in older mice are necessary to clarify whether Wfs1 has a role in energy metabolism when the disease progresses further.