The Usefulness of Captive Kept Capercaillie (Tetrao urogallus L.) as the Semen Donors for Artificial Insemination and Gene Pool Preservation In vitro

Captive breeding of birds threatened by extinction in zoological gardens or other closed aviary centres is one of the methods allowing their protection and gene pool preservation ex situ in vivo. Such birds are usually kept in captivity lifelong and serve as parents of several new generations that can be further released into natural environment, or males are used as semen donors for artificial insemination and gene banking. Therefore, the fecundity of such flocks (number of laid egg and spermatozoa quantity and quality) is very important. The aim of this study was to evaluate the usefulness of captive kept capercaillie (Tetrao urogallus L.) as semen donors in three subsequent reproductive seasons, based on the assessment of manually collected semen quality. Male response to dorso‐abdominal massage, ejaculate volume, sperm concentration, motility and morphology were evaluated individually at three succeeding years. Depending on individual male properties and year of collection, the number of positive reactions to semen collection attempts (i.e. ending with ejaculation) varied from 44.4% to 100.0%; single ejaculate volume ranged from 10 to 300 μl, spermatozoa concentration from 10 × 10⁶ per ml to 3520 × 10⁶ per ml and percentage of live morphologically normal spermatozoa from 19.3 to 80.3%. The highest average value (66.7) of semen quality factor (SQF) was noted for a 2‐year‐old male (varying from 1.9 to 258.1), while the lowest for ten‐ (4.8; varying from 0.1 to 17.0) and 7‐year‐old (6.6; varying between 0.6 and 13.6). Assuming that for AI purposes, the ejaculate quality has to be at minimum 10 SQF, obtained results indicate that majority of capercaillie kept in captivity, both young (2–3 years old) and older (up to 10 years old), can be valuable semen producers in succeeding seasons.     

Inhibition of angiotensin conversion in experimental renovascular hypertension

Constriction of the renal artery and controlled reduction of renal perfusion pressure is followed by a prompt increase in systemic renin activity and a concomitant rise in blood pressure in trained, unanesthetized dogs. The elevated blood pressure induced by the renal artery stenosis can be prevented by prior treatment with the nonapeptide Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro, which blocks conversion of angiotensin I to angiotensin II. Further, the nonapeptide can restore systemic pressure to normnal in the early phase of renovascular hypertension. These results offer strong evidence that the renin-angiotensin system is responsible for the initiation of hypertension in the unilaterally nephrectomized dog with renal artery constriction.     

Rate Constants for Charge Transfer Across Semiconductor-Liquid Interfaces

Interfacial charge-transfer rate constants have been measured for n-type Si electrodes in contact with a series of viologen-based redox couples in methanol through analyses of the behavior of these junctions with respect to their current density versus potential and differential capacitance versus potential properties. The data allow evaluation of the maximum rate constant (and therefore the electronic coupling) for majority carriers in the solid as well as of the dependence of the rate constant on the driving force for transfer of delocalized electrons from the n-Si semiconducting electrode into the localized molecular redox species in the solution phase. The data are in good agreement with existing models of this interfacial electron transfer process and provide insight into the fundamental kinetic events underlying the use of semiconducting photoelectrodes in applications such as solar energy conversion.     

Seasonality of sarcoptic mange in pigs in South Australia

Retrospective analysis of records, from July 1987 to June 1991, of 1140 inspections of slaughtered pigs from 154 swine herds in the Pig Health Monitoring Scheme of South Australia was conducted to evaluate patterns of variation in the prevalence and severity of skin lesions typical of sarcoptic mange. An increase in the severity of sarcoptic mange in winter and spring was observed. There was a substantial reduction in the severity of mange over the period of monitoring. These observations support the role of monitoring at slaughter in the management of endemic disease. They provide some basis for refining control programs for mange to improve cost-effectiveness.     

Genetic resistance of hosts and its influence on epidemiology

Evidence for the genetic control of resistance of sheep to gastrointestinal nematode infections was reviewed and compared with that of cattle to infestation with the cattle tick. Variation within sheep breeds in resistance to nematode infection is as great as that between breeds, is moderately heritable, and selection of lines of resistant sheep should result in animals carrying worm burdens around 10%-20% of those of unselected animals. The consequences of genetically resistant sheep for the epidemiology of Trichostrongylus colubriformis infection were examined with the aid of a simulation model. Predicted results were similar to those observed in cattle herds resistant to Boophilus microplus; seasonal peaks in parasite burdens were greatly reduced, and larval numbers on pasture were reduced even further. The use of genetically resistant hosts should permit a reduced frequency of anthelmintic treatment, and hence reduce the rate of development of anthelmintic resistance in the parasite.     

Effects of 2-chloro-4-acetotoluidine (CAT) toxicity on biochemical and morphological alterations in quail

Morphological changes in response to 2-chloro-4-acetotoluidine (CAT) toxicity in the quail appeared in the form of progressive necrosis of the kidney, particularly the proximal tubular epithelial cells. Changes at 32 hr after the CAT administration included vacuolar degeneration, dilatation of distal tubules containing hyaline and granular casts, overt necrosis, and deposition of urate casts in collecting tubules. There were no striking histopathological changes in the liver at 24 hr. However, small focal necrotic lesions were seen 32 hr after the CAT administration. A 40% protection against the toxicity of CAT at the lower dose was seen in quail pretreated with phenobarbital. The protection offered by phenobarbital pretreatment was attributed to a quantitative shunting of CAT and/or its reactive metabolite along the microsomal-mediated metabolic pathway of the kidney responsible for their inactivation. Administration of reduced glutathione (GSH) to quail treated with CAT offered little protection against the toxicity. The quail treated with a toxic dose of CAT had an increased level of thiobarbituric acid (TBA) reacting products in the liver, with a concomitant decrease in GSH content. This suggests that lipid peroxidation may be involved in CAT-induced hepatic damage of quail. It was hypothesized that the depletion of protective GSH stores coincident with gradual shutdown of the protective peroxidase system of the kidney may occur in a more advanced stage of CAT toxicity in quail. This would then result in a severe disturbance in renal excretion of uric acid and in frank necrosis of renal tubules.