Improved assessment of frozen/thawed mouse spermatozoa using fluorescence microscopy

Genetically modified (GM) animals are unique mutants with an enormous scientific potential. Cryopreservation of pre-implantation embryos or spermatozoa is a common approach for protecting these lines from being lost or to store them in a repository. A mutant line can be taken out of a breeding nucleus only if sufficient numbers of samples with an appropriate level of quality are cryopreserved. The quality of different donors within the same mouse line might be heterogeneous and the cryopreservation procedure might also be error-prone. However, only limited amounts of material are available for analysis. To improve the monitoring of frozen/thawed spermatozoa, commonly used in vitro fertilization (IVF) followed by embryo transfer were replaced with animal-free techniques. Major factors for assessing spermatozoa quality (i.e., density, viability, motility, and morphology) were evaluated by fluorescence microscopy. For this, a live/dead cell staining protocol requiring only small amounts of material was created. Membrane integrity was then examined as major parameter closely correlated with successful IVF. These complex analyses allow us to monitor frozen/thawed spermatozoa from GM mice using a relatively simple staining procedure. This approach leads to a reduction of animal experiments and contributes to the 3R principles (replacement, reduction and refinement of animal experiments).     

Mediastinal Schwannoma in a horse-cytologic,histologic, and immunochemical evaluation

A 31-kg mediastinal mass from a 24-year-old horse is described. Cytologic imprints contained numerous spindle cells with indistinct cytoplasm and multiple foci of palisading nuclei. Histologic sections had these same characteristics and areas of central fibrillar material between palisading nuclei (Verocay bodies). Within histologic sections, spindle cell cytoplasm had positive immunoreactivity for vimentin and S-100, whereas immunoreactivity was not detected for desmin and cytokeratin. Cytologic, histologic, and immunochemical evaluation confirmed a diagnosis of solitary schwannoma.     

ULTRASONOGRAPHIC DIAGNOSIS: CRANIAL VENA CAVA THROMBOSIS IN A COW

A 5-year-old Hereford cow was donated to Oregon State University, College of Veterinary Medicine. Two weeks before presentation the cow was treated by a left-flank laparotomy to correct a uterine torsion that revealed an excessive amount of abdominal fluid and a full term dead fetus. Ultrasonographic evaluation of the right cranioventral thoracic cavity was performed owing to physical examination (muffled heart sounds, areas of silence) and thoracocentesis findings suggestive of pleuritis. Ultrasonography revealed hypoechoic pleural effusion and a mass of mixed echogenicity visible within the right atrial lumen extending into the cranial vena cava. A diagnosis of cranial vena cava thrombosis was demonstrated at necropsy. The clinical, ultrasonographic, and pathological features of this less common condition (cranial vena cava thrombosis) in cattle are discussed.     

Ocular morphology of the Leatherback sea turtle (Dermochelys coriacea)

Objective The Leatherback sea turtle is the largest extant reptile and the sole member of the family Dermochelyidae. Here, the eye of this critically endangered marine turtle was investigated to determine the anatomy, optics, and optical sensitivity. Animals studied Three Leatherback sea turtles, Dermochelys coriacea. Results The eye is small in proportion to body size of the adult compared to other vertebrates, with prominence of the retractor bulbi and pyramidalis muscles. The nictitans shows extensive folding of the bulbar conjunctiva as an apparent mechanism to increase the surface area for mucus secretion. The intraocular anatomy is consistent with an eye adapted to aquatic vision with minimal curvature of the cornea, a near‐spherical lens, deep ciliary cleft and highly vascularized ciliary body. The optical sensitivity, a measure of the sensitivity to light of a given optical system, is higher than in other marine turtles studied but lower than those found in teleost fish that share a habitat with the Leatherback sea turtle. Conclusions The Leatherback sea turtle shows ocular features that are characteristic of Chelonians with similarities to aquatic mammals. The calculated optical sensitivity suggests that compared to pelagic fishes, for instance, the Leatherback sea turtle eye is not particularly well adapted for vision in dim light even though this species is known to venture into deep, dark waters, and might feed at night.     

Effect of long-term selection for increased leanness on meat and eating quality traits in Duroc swine

A study was conducted to evaluate differences in meat and eating quality traits between purebred Duroc pigs sired by boars currently available and pigs sired by boars from the mid 1980s. Two lines were developed by randomly allocating littermate and half-sib pairs of females to matings by current time period (CTP) or old time period (OTP) boars. Matings by CTP boars were made using fresh semen, and matings by OTP boars were via frozen semen. All available barrows and randomly selected gilts were sent to a commercial abattoir and used for meat and eating quality evaluation. A total of 178 pigs from 23 CTP sires and 99 pigs from 15 OTP sires, across 2 replications and at a mean live weight of 109 kg, were slaughtered and analyzed. Chemical intramuscular fat percentage was determined by lab analysis of a slice from the LM at the 10th rib. Additional meat and eating quality traits measured on the LM were Minolta reflectance and Hunter L color (24 h); pH (24 h and 7 d); water-holding capacity; subjective visual scores for color, marbling, and firmness (48 h); Instron tenderness; cooking loss; and trained sensory panel evaluations (7 d). Time period differences were assessed by use of a mixed model that included fixed effects of sire time period, replication, sex, contemporary group, and the interaction of sex x time period. The random effect of dam and the random effect of sire nested within time period were also included. Loins from pigs sired by OTP boars had greater intramuscular fat (3.48 vs. 3.09%) and visual marbling scores (3.54 vs. 3.07), required less Instron force (5.31 vs. 5.98 kg) to compress, and had darker visual color scores (4.09 vs. 3.87) compared with loins from pigs sired by CTP boars (P < 0.05). No differences were observed between time periods for Minolta reflectance, Hunter L (24 h), water-holding capacity, pH (24 h and 7 d), or subjective firmness scores. Trained sensory evaluations revealed more pork flavor and less off-flavor (P < 0.05) for OTP-sired pigs; however, no differences in tenderness score, juiciness score, chewiness score, or cooking loss were found between lines. Long-term selection response in carcass composition has been at the expense of meat and eating quality traits.     

Internal validation of a computerized systems model for health management decision support in growing hogs

A study was designed to conduct an internal validation of a computerized systems model for health management decision support in growing hogs. Evaluation focused on both the alpha-beta tracker, which was employed to predict underlying system variables, and the simulation model itself, which predicted system performance. Both mean absolute prediction error and Theil's u₂ statistic were calculated. Simulation scenarios were designed to highlight specific aspects of the model. In addition, a case example was developed to demonstrate the model's logical consistency and its applicability for assessing the economics of health management decisions. Use of the alpha-beta tracker to project data series, including pig deaths and disease prevalence rates at slaughter, was largely unsuccessful. The model consistently predicted hogs marketed such that 0 < u₂ < 1. Also, decreased disease rates improved both physical and financial performance as expected. Depending on the quarter involved, the maximum bid to achieve a 50% decrease in the prevalence rates of pneumonia at slaughter and a 10% decrease in the prevalence rates of atrophic rhinitis at slaughter ranged from $0.15 to $0.37 per hog marketed for one producer. Future validation efforts should emphasize data quality and the effects of disease on production while seeking system application in a commercial production setting.