In vitro studies of Norwegian Red bovine semen immobilized and cryopreserved in alginate solid gel network

Development of new semen cryopreservation techniques improving sperm survival and ensuring availability of viable spermatozoa for a prolonged time‐period after AI is promising tools to reduce sensitivity of timing of AI and enhance overall fertility. The SpermVital^® technology utilizes immobilization of bull spermatozoa in a solid network of alginate gel prior to freezing, which will provide a gradual release of spermatozoa after AI. The objective of this study was to compare post‐thaw sperm quality and in vitro sperm survival over time of Norwegian Red bull semen processed by the SpermVital^® (SV) technology, the first commercialized production line of SpermVital^® (C) and by conventional procedure applying Biladyl^® extender (B). Post‐thaw sperm motility was not significantly different between SV, C and B semen (p > .05). However, sperm viability and acrosome intactness were higher for SV than C and B semen (p < .05). Small differences in DNA quality were observed (p < .05). Sperm viability after storage in uterus ex vivo was higher for SV than for C semen (p < .05). Furthermore, sperm survival in vitro over time at physiological temperature was significantly higher for SV semen than C semen as well as B semen during the incubation period of 48 hr (p < .05). In conclusion, the SpermVital^® technology is improved and is more efficient in conserving post‐thaw sperm quality and results in higher sperm viability over time in vitro for SV than for C and B semen.     

CONTRAST-ENHANCED ULTRASONOGRAPHY IN NORMAL CANINE LIVER. EVALUATION OF IMAGING AND SAFETY PARAMETERS

Contrast-enhanced ultrasonography, a new imaging modality in veterinary medicine, can provide data on tissue perfusion. The objective of this study was to use the ultrasonographic contrast agent SonoVue to evaluate various transit time indices in the normal canine liver, to examine the effect of anesthesia on these parameters, and to evaluate the safety of this agent in dogs. The liver of 11 healthy dogs was studied by ultrasound during an intravenous bolus injection of SonoVue. Each dog underwent the examination twice, first with and later without the use of anesthesia. A time-intensity curve was generated from a selected region of interest within the liver from each scanning session. Ratios derived from peak enhancement, time to peak enhancement, up-slope and full-width half-maximum (FWHM) of the curve were calculated from the time-intensity curves, and are reported. There were no statistically significant differences (P > 0.05) in peak enhancement, up-slope and FWHM between dogs that were anesthetized and dogs that were not. Time to peak enhancement, however, was significantly shorter when the dogs were anesthetized than when they were nonanesthetized (P < 0.05). There were no biologically significant changes in clinical laboratory findings. This study indicates that contrast-enhanced ultrasound using SonoVue gives reproducible liver perfusion data, and appears to be a safe and well-tolerated agent for use in dogs. When considering normal values, the use of anesthetic drugs has to be considered.     

Short-term biological variation of clinical chemical values in Dumeril's monitors (Varanus dumerili).

Plasma biochemical values are routinely used in the medical management of ill reptiles, and for monitoring the health of clinically normal animals. Laboratory tests, including clinical biochemical values, are subject to biological and analytical variation, the magnitude of which determines the utility of population-based reference ranges for the detection of abnormal results in the individual animal. Nested analysis of variance of repeated measurements allows the variance to be broken into within-individual, between-individual, and analytical variation. When the within-individual variation is large and the interindividual variation is low, a sample may be accurately classified as normal or abnormal based on a population-based reference interval. However, if the intraindividual variation is low and the interindividual variation high, population-based reference intervals are of limited value as the ranges for an individual encompass only a part of the conventional reference interval. Between-lizard, within-lizard, and analytical components of variance were assessed by nested analysis of variance for 16 commonly measured plasma biochemical parameters in eight healthy adult Dumeril's monitors (Varanus dumerili). Albumin, cholesterol, phosphate, calcium, sodium, and total protein demonstrated levels of individuality suggesting that comparison of a single measurement to a conventional population-based reference range may be too insensitive to detect small but significant alterations in the value for that animal. Only for potassium and AST did the index of individuality suggest that the use of reference values may be warranted. Uric acid, globulin, glucose, and amylase fell in a gray zone, where population-based ranges should be used with caution. The critical difference indicates the difference between two consecutive analytical results that may be safely ascribed to natural variation. In the present study critical difference varied from 7 and 11%, respectively, for sodium and chloride to 75 and 125% for uric acid and AST.     

Assessing the influence of mechanical ventilation on blood gases and blood pressure in rattlesnakes

ObjectiveTo characterize the impact of mechanical positive pressure ventilation on heart rate (HR), arterial blood pressure, blood gases, lactate, glucose, sodium, potassium and calcium concentrations in rattlesnakes during anesthesia and the subsequent recovery period.Study designProspective, randomized trial.AnimalsTwenty one fasted adult South American rattlesnakes (Crotalus durissus terrificus).MethodsSnakes were anesthetized with propofol (15 mg kg⁻¹) intravenously, endotracheally intubated and assigned to one of four ventilation regimens: Spontaneous ventilation, or mechanical ventilation at a tidal volume of 30 mL kg⁻¹ at 1 breath every 90 seconds, 5 breaths minute⁻¹, or 15 breaths minute⁻¹. Arterial blood was collected from indwelling catheters at 30, 40, and 60 minutes and 2, 6, and 24 hours following induction of anesthesia and analyzed for pH, PaO₂, PaCO₂, and selected variables. Mean arterial blood pressure (MAP) and HR were recorded at 30, 40, 60 minutes and 24 hours.ResultsSpontaneous ventilation and 1 breath every 90 seconds resulted in a mild hypercapnia (PaCO₂ 22.4 ± 4.3 mmHg [3.0 ± 0.6 kPa] and 24.5 ± 1.6 mmHg [3.3 ± 0.2 kPa], respectively), 5 breaths minute⁻¹ resulted in normocapnia (14.2 ± 2.7 mmHg [1.9 ± 0.4 kPa]), while 15 breaths minute⁻¹ caused marked hypocapnia (8.2 ± 2.5 mmHg [1.1 ± 0.3 kPa]). Following recovery, blood gases of the four groups were similar from 2 hours. Anesthesia, independent of ventilation was associated with significantly elevated glucose, lactate and potassium concentrations compared to values at 24 hours (p < 0.0001). MAP increased significantly with increasing ventilation frequency (p < 0.001). HR did not vary among regimens.Conclusions and clinical relevanceMechanical ventilation had a profound impact on blood gases and blood pressure. The results support the use of mechanical ventilation with a frequency of 1–2 breaths minute⁻¹ at a tidal volume of 30 mL kg⁻¹ during anesthesia in fasted snakes.     

Resistance to the cabbage root fly, Delia radicum, within Brassica fruticulosa

Two transgenic Bt rice lines, KMD1 and KMD2, both containing a synthetic cry1Ab gene from Bt, were crossed with conventional rice varieties. The inheritance of resistance to SSB of KMD1 and KMD2was investigated through LSB and field examination of their progenies, e.g. F₁, BC₁ and F₂ populations. In LSBs, 100.0% of newly hatched SSB larvae died on the second day after feeding on leaf tissues of F₁ and GUS positive BC₁ plants, of which the area of leaf tissues consumed by SSB is also similar to that of transgenic parents. These results imply that the resistance of Bt rice to SSB is dominantly controlled and could be easily exploited in hybrid rice production. Field evaluation showed that segregation ratios for SSB resistance to susceptibility in BC₁ populations fit the ratio of 1:1, which was also confirmed by LSBs. However, in F₂ populations, the ratio was significantly smaller than 3:1 for resistant to susceptible plants in all 6 indica × japonica (KMD1 and KMD2) crosses, though it fitted 3:1 in all 4 japonica × japonica crosses. The results implied that the resistance of Bt rice to SSB was controlled by a dominant gene which was present in a homozygous condition in both KMD1 and KMD2, but the inheritance could be affected by other factors. Assays for Cry1Ab protein showed that, in most crosses, the content of Cry1Ab is significantly higher in leaves of GUS positive F₁, BC₁ and F₂ plants than that in transgenic Bt parent plants, which accounts for the high resistance observed in these plants to SSB. This revised version was published online in July 2006 with corrections to the Cover Date.     

Flower induction in seedlings of Aster novi-belgii and selection before and after vegetative propagation

Bolting and flowering of Aster novi-belgii seedlings as well as correlations between characteristics within seedling populations and between seedlings and their vegetatively propagated offspring were investigated in order to improve breeding efficiency. In seedlings of A. novi-belgii, flower induction was observed without vernalization. Seedlings initially formed a rosette, but bolting was a prerequisite for development of a normal flowering shoot. Bolting was promoted by long photoperiods as compared to short days. The shortest time from sowing to anthesis was recorded when plants were grown under long photoperiods until the main stem was at least 5 cm long, and then moved to short photoperiods. A large variation in time to anthesis, plant height, branching ability, and flower size and color was found among the seedlings within all crosses. Magnitude and significance of correlations between some characteristics varied among crosses. The more consistent correlations seem mainly to be due to natural courses of plant growth and development. High correlations between seedling characteristics and their vegetatively propagated offspring were only found for flower hue. Lower, but significant correlations were found for flower color intensity, plant height and branching ability. There were no significant correlations for the time-to-anthesis between the two groups of plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Resorptive tooth root lesions in the Malayan tapir (Tapirus indicus)

Facial abscessation and osteomyelitis due to dental disease is commonly seen in the Malayan tapir (Tapirus indicus), but little is known about the prevalence or etiology of these lesions. To determine the prevalence of dental ailments, 56 skulls and mandibles of deceased Malayan tapirs were visually and radiographically evaluated. Dental lesions were scored according to severity, and individuals were classified according to their age (juvenile/ young adult/adult) and origin (captive/free ranging). All of the lesions identified were of a resorptive nature. seemingly originating at the cementoenamel junction and burrowing towards the center of the tooth. Overall, 27% of the investigated skulls presented radiolucent dental lesions. The prevalence among captive animals was 52% (13/25), while only 6% (2/31) of the free-ranging tapirs had dental lesions. The second, third, and fourth premolars and first molar were the teeth most commonly affected, and the mandibular teeth were more often involved than the maxillary dentition. This study demonstrates a high prevalence of resorptive dental lesions in captive Malayan tapirs and provides a strong indication that age and captivity are significant risk factors in the development of these lesions. Dental disease, Malayan tapir, radiology, resorptive lesions, Tapirus indicus.