Spermatic and oxidative profile of domestic cat (Felis catus) epididymal sperm subjected to different cooling times (24, 48 and 72 hours)

Cooling stored epididymal samples for several days allows facilities to transport and process genetic material post‐mortem. Improvements to this practice allow the preservation of sperm from domestic cats, which are the ideal study model for wild felids. However, the modifications in spermatic features and the oxidative profile are not fully understood in cats. This information is necessary for the development of biotechniques, such as new extenders for cryopreservation. Therefore, the purpose of this study was to evaluate the spermatic and oxidative profile in samples from the epididymal cauda of domestic cats cooled at 5°C for 24, 48 and 72 hr. Spermatozoa were collected from the epididymis cauda. Evaluations consisted of computer‐assisted sperm analysis (CASA), plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, sperm DNA integrity (toluidine blue), mitochondrial activity (3′3 diaminobenzidine), activity of the antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), measurement of lipid peroxidation (TBARS) and protein oxidation. A decrease in sperm motility parameters was observed after 72 hr of cooling (i.e. total and progressive) with a higher percentage of minor (37.7 ± 6.3%) and total defects (53.4 ± 6.3%). Additionally, a decrease in high mitochondrial activity (Class I: 16.6 ± 2.2%) occurred after 72 hr. The decrease in motility rates after a long cooling time probably was caused by the increase in sperm abnormalities. A long cooling time causes cold shock and mitochondrial exhaustion, but there was no observed change with the oxidative stress condition. Therefore, cat epididymal sperm stored at 5°C appear to maintain a high quality for up to 48 hr of cooling time.     

A fast,low‐cost and efficient method for the diagnosis of sperm DNA fragmentation in several species

Sperm DNA fragmentation is a condition that interferes directly in the reproductive efficiency. Currently, there are several methods for assessing the sperm DNA integrity, such as Alkaline Comet, TUNEL and Sperm Chromatin Structure Assay. However, many of these techniques are laborious and require high‐precision equipment. Thus, the development of new techniques can optimize the evaluation of sperm DNA damage. Therefore, the aim of this study was to standardize the toluidine blue (TB) stain technique for the analysis of DNA fragmentation of dog, cat, bull, stallion and ram spermatozoa. For this purpose, we used six animals of each specie (n = 30), in reproductive age. Sperm was collected by different methods according to the particularities of each species, and such samples were divided into two aliquots: a sperm sample was kept at 5°C (considered as intact sperm DNA), and the remaining samples were submitted to the induction of DNA fragmentation by exposure to ultraviolet light for 4 hr. Samples were then mixed with the intact sample to obtain known and progressive proportions of sperm with fragmented DNA (0%, 25%, 50%, 75% and 100%). Semen smears were performed and subjected to staining with TB. Blue‐stained spermatozoa were considered to have DNA fragmentation. We observed high linear regression coefficients between the expected proportion of damaged DNA and the results of TB for dog, cat, ram, bull and stallion samples. In conclusion, TB stain was considered a fast and effective technique for the study of spermatozoa DNA in several species.     

Biocontrol efficacy of Colletotrichum truncatum for hemp sesbania (Sesbania exaltata) is enhanced with unrefined corn oil and surfactant

In greenhouse and field experiments, an oil-in-water emulsion of unrefined corn oil and Silwet L-77 increased the biological weed control efficacy of Colletotrichum truncatum (Schw.) Andrus et Moore for control of the weed, hemp sesbania ( Sesbania exaltata [Raf.] Rydb. ex A.W. Hill). The surfactant – corn oil emulsion stimulated germination and appressoria formation in vivo and in vitro and delayed the need for dew. We hypothesize that the corn oil protected the conidia from desiccation during the dew-free period and the surfactant stimulated spore germination and appressoria formation. In field experiments conducted over 3 years, a single application of a 50% (v/v) unrefined corn oil tank mixture containing 0.2% (v/v) Silwet L-77 surfactant controlled hemp sesbania in soybeans an average of 95%. Aqueous fungal suspensions or adjuvants alone did not visually affect or control hemp sesbania. The soybean yields were significantly higher in the plots where weeds were effectively controlled. These results suggest that formulating C. truncatum in unrefined corn oil and surfactant greatly increases its infectivity and the biocontrol potential of this pathogen.     

Kisspeptin,c‐Fos and CRFR Type 2 Co‐expression in the Hypothalamus after Insulin‐Induced Hypoglycaemia

Normal reproductive function is dependent upon availability of glucose and insulin‐induced hypoglycaemia is a metabolic stressor known to disrupt the ovine oestrous cycle. We have recently shown that IIH has the ability to delay the LH surge of intact ewes. In the present study, we examined brain tissue to determine: (i) which hypothalamic regions are activated with respect to IIH and (ii) the effect of IIH on kisspeptin cell activation and CRFR type 2 immunoreactivity, all of which may be involved in disruptive mechanisms. Follicular phases were synchronized with progesterone vaginal pessaries and at 28 h after progesterone withdrawal (PW), animals received saline (n = 6) or insulin (4 IU/kg; n = 5) and were subsequently killed at 31 h after PW (i.e., 3 h after insulin administration). Peripheral hormone concentrations were evaluated, and hypothalamic sections were immunostained for either kisspeptin and c‐Fos (a marker of neuronal activation) or CRFR type 2. Within 3 h of treatment, cortisol concentrations had increased whereas plasma oestradiol concentrations decreased in peripheral plasma (p < 0.05 for both). In the arcuate nucleus (ARC), insulin‐treated ewes had an increased expression of c‐Fos. Furthermore, the percentage of kisspeptin cells co‐expressing c‐Fos increased in the ARC (from 11 to 51%; p < 0.05), but there was no change in the medial pre‐optic area (mPOA; 14 vs 19%). CRFR type 2 expression in the lower part of the ARC and the median eminence was not altered by insulin treatment. Thus, disruption of the LH surge after IIH in the follicular phase is not associated with decreased kisspeptin cell activation or an increase in CRFR type 2 in the ARC but may involve other cell types located in the ARC nucleus which are activated in response to IIH.     

THE VALUE OF RADIOGRAPHIC SCREENING FOR METALLIC PARTICLES IN THE EQUINE FOOT AND SIZE OF RELATED ARTIFACTS ON LOW‐FIELD MRI

Magnetic susceptibility artifacts as a result of metal debris from shoeing are a common problem in magnetic resonance imaging of the equine foot. Our purpose was to determine the suitability of radiography as a screening tool for the presence and location of metallic particles in the equine foot and to predict the size of the resultant magnetic susceptibility artifact. Radiography had 100% sensitivity for detection of metal particles ≥1 mm diameter. Metal particles of known diameter were placed within the hoof wall of 22 cadaver feet and scanned with a low‐field strength MR imaging unit (0.21 T). Magnetic resonance images were characterized by a signal void with a hyperintense rim and adjacent image distortion at the level of the known metal location. T2* weighted sequences were the most and fast spin echo (FSE) sequences the least affected. For all four sequences (T1 gradient echo [GRE]; T2*W GRE; T2 FSE; and short tau inversion recovery FSE), linear relationships were observed between particle and resultant artifact size. Magnetic susceptibility artifact size, location and superimposition on clinically relevant anatomic structures can be predicted radiographically for particles larger than 1 mm. If metal debris cannot be removed, the least artifact‐prone FSE sequences should be selected.     

Pharmacokinetics of thiopentone in the horse

Abass, B.T., Weaver, B.M.Q., Staddon, G.E., Waterman, A.W. Pharmacokinetics of thiopentone in the horse. J. vet. Pharmacol. Therap . 17 , 331–338.
The pharmacokinetics of thiopentone sodium administered intravenously as a single dose (11 mg/kg) were studied in acepromazine pre-medicated horses and ponies in which anaesthesia was maintained with either halothane (Group 1) or isoflurane (Group 2). The results showed that the disposition kinetics of thiopentone in horses and ponies were best described by a three-compartment open model. In plasma, a very short initial distribution phase in both horses and ponies, half-life 1.4 ± 1.2 min (mean ± SD) and 1.3 ± 0.7 min, respectively, was obtained, which was followed by a second comparatively slower redistribution phase, half-life 16 ± 12 min and 11 ± 5 min, respectively. The volume of distribution for the drug was large, especially in the ponies which received isoflurane (1127 ± 86 ml/kg). compared to the horses which received halothane (742 ± 89 ml/kg). The drug had a somewhat shorter elimination half-life in the horses (147 ± 21 min) than in the ponies (222 ± 44 min), but no obvious difference in clearance of the drug was observed between the horses (3.5 ± 0.5 ml/min/kg) and ponies (3.6 ± 0.8 ml/min/kg).     

Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae

BACKGROUND: Dengue fever is a severe public health problem for several countries. In order to find effective larvicides to aid control programs, the structure‐activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae were evaluated. Additionally, the composition and larvicidal activity of Syzygium aromaticum essential oil was assessed. RESULTS: Four compounds representing 99.05% of S. aromaticum essential oil have been identified. The essential oil was active against Ae. aegypti larvae (LC₅₀ = 62.3 and 77.0 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity of eugenol, the major compound of the essential oil, was further evaluated (LC₅₀ = 93.3 and 71.9 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity and structure‐activity relationships of synthetic derivatives of eugenol were also assessed. The larvicidal activity of the derivatives varied between 62.3 and 1614.9 ppm. Oxidation of eugenol allylic bond to a primary alcohol and removal of the phenolic proton resulted in decreased potency. However, oxidation of the same double bond in 1‐benzoate‐2‐methoxy‐4‐(2‐propen‐1‐yl)‐phenol resulted in increased potency. CONCLUSION: Structural characteristics were identified that may contribute to the understanding of the larvicidal activity of phenylpropanoids. The present approach may help future work in the search for larvicidal compounds. Copyright © 2012 Society of Chemical Industry     

MAGNETIC RESONANCE IMAGING FINDINGS OF EQUINE SOLAR PENETRATION WOUNDS

The magnetic resonance (MR) imaging features, signalment, clinical history and outcome of 55 horses with a penetrating sole injury were evaluated. Our aim was to describe MR imaging findings within the hoof capsule, assess the utility of the technique and give recommendations for the optimal MR imaging protocol to evaluate such injuries. Data from five equine hospitals were analyzed retrospectively. The tract was more likely to be visualized in animals scanned within the first week postinjury. There was no significant predisposition based on breed, age, or gender. T2*W transverse sequences were the most useful for assessment of solar penetrations due to their orientation perpendicular to the deep digital flexor tendon, the reduced scanning time, and the T2* capability of enhancing magnetic susceptibility caused by hemorrhage.     

Assessing obesity in adult dogs and cats presenting for routine vaccination appointments in the North Island of New Zealand using electronic medical records data

Aims: To assess the prevalence of obesity in adult dogs and cats presented to first-opinion veterinary clinics in the North Island of New Zealand for routine vaccination appointments, using electronic medical records.

Methods: Ten first-opinion veterinary clinics across the North Island of New Zealand provided electronic medical records for all routine vaccination appointments for adult (>1 year old) dogs and cats between 1 January 2011 and 30 June 2016. Animals with a body condition score (BCS) of 6 or 7 on a 9-point scale and 4 on a 5-point scale were classified as overweight; those with a BCS of 8 or 9 on a 9-point scale and 5 on a 5-point scale were classified as obese. A total of 106,144 records were available over the study period, of which 48,041 (45.2%) had both a recorded weight and BCS.

Results: Of the 24,247 records for dogs with both BCS and weight, 6,324 (26.1%) were classified as overweight, and 551 (2.3%) as obese. The prevalence of dogs classified as overweight or obese was highest in dogs aged between 5–13 years. The odds of desexed dogs being classified as overweight or obese was greater than the odds for intact dogs (OR=1.42 (95% CI=1.29–1.57), p<0.001) adjusting for the effects of age. Of the 23,794 records for cats with a recorded weight and BCS, 5,222 (21.9%) were classified as overweight, and 622 (2.6%) as obese. The prevalence of cats classified as overweight or obese was highest in cats aged between 5–11 years. The odds of desexed cats being classified as overweight or obese tended to be greater than the odds for intact cats (OR=1.14 (95% CI=0.98–1.31); p=0.075), adjusting for the effects of age.

Conclusions: Although there are limitations with using electronic medical records to estimate the prevalence of obesity in companion animal populations, the results highlight that a significant number of animals presenting for routine vaccination appointments were classified as overweight or obese.

Clinical Relevance: It is important for veterinarians to record both patient body condition and weight during routine preventative care appointments to allow accurate ongoing monitoring of trends in obesity at both the patient and population levels.

Abbreviations: BCS: Body condition score