Use of Powdered Egg Yolk vs Fresh Egg Yolk for the Cryopreservation of Ovine Semen

Egg yolk is a common additive to sperm cryopreservation diluents. Because of its animal origin, however, it also represents a potential risk of microbiological contamination in the diluent. This potential contamination can be avoided by using powdered egg yolk, instead of fresh egg yolk, as it is pasteurized. This study was conducted to determine ram sperm cryosurvival was affected by the type of egg yolk used (powdered egg yolk or fresh egg yolk) and by yolk concentration (10, 15 or 20%) in the diluent. Microbiological analyses were also performed to quantify the microbiological contamination in the diluents containing the two types of egg yolk. Sperm cryosurvival was determined by motility and morphology analyses after thawing. Motility parameters were assessed using a computer-assisted sperm analysis (CASA) system, and the percentage of sperm with a normal apical ridge was evaluated using a differential interference contrast microscope. No significant differences were observed between diluents in the percentage of sperm with normal apical ridge. However, higher percentages of total motile cells were observed for samples containing powdered egg yolk (69%) compared to samples containing fresh egg yolk (60%). However, sperm in diluents containing fresh egg yolk, exhibited higher values for average-path velocity, straight-line velocity and beat cross frequency and lower values for amplitude of lateral head displacement (p <0.05), compared to cells in diluents containing powdered egg yolk. Microbiological contamination was similar (<200 CFU/ml) in both diluents, and no bacterial growth was observed in either, when antibiotics were added. Therefore, powdered egg yolk can be effective used in diluents for the freezing of ram semen. However, the in vivo fertility of sperm frozen in diluents containing powdered egg yolk should be tested, as some motility parameters were different for sperm treated with powdered egg yolk compared to fresh egg yolk.     

The elemental composition of asteroid 433 eros: results of the NEAR-shoemaker X-ray spectrometer

We report major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions during the period of May to July 2000. Low aluminum abundances for all regions argue against global differentiation of Eros. Magnesium/silicon, aluminum/silicon, calcium/silicon, and iron/silicon ratios are best interpreted as a relatively primitive, chondritic composition. Marked depletions in sulfur and possible aluminum and calcium depletions, relative to ordinary chondrites, may represent signatures of limited partial melting or impact volatilization.     

Carbon,nitrogen and phosphorus leaching after site preparation at a boreal forest clear-cut area

Clear-cutting followed by mechanical site preparation is the major disturbance influencing nutrient and water fluxes in Fennoscandian boreal forests. The effects of soil harrowing on the fluxes of dissolved organic carbon (DOC), dissolved nitrogen compounds (organic N, NH₄⁺ and NO₃⁻) and water soluble phosphorus (PO₄³⁻) through a podzolic soil were studied in a clear-cut in eastern Finland for 5 years. The old, mixed coniferous stand was clear-cut and stem only harvested in 1996 followed by soil harrowing in 1998 and planting in June 1999. Zero-tension lysimeters were used to collect soil water from below different soil horizons in the three types of microsites that resulted from site preparation treatment: low ridges (25% of clear-cut area), shallow furrows (30%) and the undisturbed soil (45%). After soil harrowing, the leaching of DOC, N and P from below the B-horizon increased compared to pre-treatment levels. However, the increases were short-lasting; 1–2 years for inorganic N and P, and 5 years for DOC and organic N. The highest concentrations were associated with the ridges and lowest with the furrows, reflecting the differences in amount of organic matter present in each microsite type and, for N, to enhanced mineralization and nitrification. Leaching from below the B-horizon over the 5 years following soil harrowing for the whole clear-cut area was 36.5 kg ha⁻¹ for DOC, 0.88 kg ha⁻¹ for NH₄-N, 0.46 kg ha⁻¹ for NO₃-N, 1.24 kg ha⁻¹ for organic N and 0.09 kg ha⁻¹ for PO₄-P. Site preparation increased temporarily the risk for nutrient leaching into watercourses and groundwater from the clear-cut area but soil fertility was not affected since the leached amounts remained small. The main reasons for the observed low leaching values were the rapid recovery of ground vegetation and low N deposition loads.     

Cross‐sectional observational survey of serum biochemistry values in a population of 69 adult female alpacas (Vicugna pacos) in South Australia

Blood samples were collected from 69 ‘healthy’ female alpacas aged ≥12 months from 11 properties in South Australia. The 10–90 percentile ranges of the 16/19 analytes measured in this sample population were within the published ranges of four healthy alpaca populations from other geographic locations. Marginal exceptions were glutamate dehydrogenase and bicarbonate. Potassium was notably elevated, probably because of haemolysis of some samples. The sample size was insufficient to provide the appropriate statistical power to define diagnostic references ranges according to international standards. The health status of the sample population of alpacas was presumptive based on a physical examination.