Effects of Gonadotropins on In Vitro Maturation and of Electrical Stimulation on Parthenogenesis of Canine Oocytes

The objective of this study was to determine the effects of gonadotropins on in vitro maturation (IVM) and electrical stimulation on the parthenogenesis of canine oocytes. In experiment I, cumulus oocyte complexes were collected from ovaries at a random phase of the oestrus cycle and cultured on maturation medium treated with hCG or eCG for 48 or 72 h. There were no significant differences in the effects on the metaphase II (MII) rate between the hCG and eCG treatment groups over 48 h (5.4% vs 5.5%). The MII rate in the co-treatment group of hCG and eCG for 48 h was higher than in each hormone treated group (15.5%, p < 0.05). In experiment 2, the parthenogenetic effect on oocyte development, at various electrical field strengths (1.0, 1.5, 2.0 kV/cm DC) for 60 or 80 μs with a single DC pulse after IVM on the co-treatment of hCG and eCG, was examined. The rate of pronuclear formation (37.1%) in electrical activation at 1.5 kV/60 μs without cytochalasin B (CB) was higher than that of oocytes activated in the other groups (p < 0.05). However, we did not observe the cleavage stages. Also, CB did not influence parthenogenesis of canine oocytes. The results showed that the pronucleus formation rate, indicative of the parthenogenesis start point, could be increased by electrical stimulation. Therefore, these results can provide important data for the parthenogenesis of canine oocytes and suggest the probability of parthenogenesis in canines.     

Oral administration of different formulations of ascorbic acid to the horse

The absorption of crystalline ascorbic acid, ascorbyl palmitate, ascorbyl stearate and a formulation of ascorbic acid was investigated in six mature Thoroughbred horses following oral administration. It was found that ascorbyl palmitate gave both highest plasma concentrations and greatest area under the curve (AUC) for ascorbic acid. Least variation between animals also occured for this preparation. No apparent absorption was seen in some animals given ascorbic acid or ascorbyl stearate.     

Selective pancreatic enzyme secretion due to a new peptide called chymodenin

Chymodenin, a peptide newly isolated from porcine duodenum, elicited a rapid threefold increase in secretion of chymotrypsinogen while increasing secrelion of total protein by only, about 40 percent; lipase secretion was unaffected. The pancreas appears able, under chymodenin stimulation, to rapidly alter the transport of an individual enzyme as opposed to producing en masse secretion of enzyme.     

Workplace bullying and relationships with health and performance among a sample of New Zealand veterinarians

AIM: To examine the relationships between workplace bullying, destructive leadership and team conflict, and physical health, strain, self-reported performance and intentions to quit among veterinarians in New Zealand, and how these relationships could be moderated by psychological capital and perceived organisational support.

METHODS: Data were collected by means of an online survey, distributed to members of the New Zealand Veterinary Association. Participation was voluntary and all responses were anonymous and confidential. Scores for the variables measured were based on responses to questions or statements with responses categorised on a linear scale. A series of regression analyses were used to assess mediation or moderation by intermediate variables on the relationships between predictor variables and dependent variables.

RESULTS: Completed surveys were provided by 197 veterinarians, of which 32 (16.2%) had been bullied at work, i.e. they had experienced two or more negative acts at least weekly over the previous 6 months, and nine (4.6%) had experienced cyber-bullying. Mean scores for workplace bullying were higher for female than male respondents, and for non-managers than managers (p<0.01). Scores for workplace bullying were positively associated with scores for destructive leadership and team conflict, physical health, strain, and intentions to quit (p<0.001). Workplace bullying and team conflict mediated the relationship between destructive leadership and strain, physical health and intentions to quit. Perceived organisational support moderated the effects of workplace bullying on strain and self-reported job performance (p<0.05).

CONCLUSIONS: Relatively high rates of negative behaviour were reported by veterinarians in this study, with 16% of participants meeting an established criterion for having been bullied. The negative effects of destructive leadership on strain, physical health and intentions to quit were mediated by team conflict and workplace bullying. It should be noted that the findings of this study were based on a survey of self-selected participants and the findings may not represent the wider population of New Zealand veterinarians.     

U/Pb zircon geochronology and tempo of the end-permian mass extinction

The mass extinction at the end of the Permian was the most profound in the history of life. Fundamental to understanding its cause is determining the tempo and duration of the extinction. Uranium/lead zircon data from Late Permian and Early Triassic rocks from south China place the Permian-Triassic boundary at 251.4 +/- 0.3 million years ago. Biostratigraphic controls from strata intercalated with ash beds below the boundary indicate that the Changhsingian pulse of the end-Permian extinction, corresponding to the disappearance of about 85 percent of marine species, lasted less than 1 million years. At Meishan, a negative excursion in delta13C at the boundary had a duration of 165,000 years or less, suggesting a catastrophic addition of light carbon.     

Serial Transrectal Ultrasonography for Monitoring the Reproductive Activity of the Asiatic Black Bear (Ursus thibetanus ussuricus)

This study evaluated the structural changes in the reproductive tract of Asiatic black bears using serial transrectal ultrasonography. In addition, the ultrasonographic observations were compared with the results of vaginal cytology and hormonal analyses. The collection of blood for hormonal analysis, vaginal cytology and transrectal ultrasonography was performed in two bears (Bears 1 and 2) from June 2011 to August 2013 without mating and in a third bear (Bear 3) from April to December 2012, allowing natural mating. Serial ultrasonographic observations showed cyclic changes in ovarian structures (e.g. emergence of small follicles, growth and ovulation of dominant follicles and corpus luteum (CL) formation) during the reproductive cycles of the three bears. The diameter of the uterine horns remained similar throughout the reproductive cycle in Bears 1 and 2, and it remained similar from April until October, but an enlargement containing foetuses was observed in Bear 3 in December. The ultrasonographic observations were consistent with the data obtained through vaginal cytology and progesterone analysis during the reproductive cycle. An average of 4.0 (±0.4) dominant follicles was observed during the oestrous stage (May‐August), during which the superficial cells accounted for >90% of the total vaginal cells. In addition, the detection of an average of 2.6 (±0.2) CL was associated with increased plasma progesterone concentrations (3.0 ± 0.4 ng/ml) between June and December (near hibernation). In conclusion, serial transrectal ultrasonography demonstrated yearly oestrous (ovulation) cycles via follicular dynamics and CL formation on ovaries, accordingly with vaginal cytology and hormonal level in the Asiatic black bear.