Oxytetracycline (OTC) pharmacokinetic values in plasma and bile were ascertained after IV administration of the drug. At 6 hours after administration of 1 mg of OTC/kg of body weight, 2.15% of the dose was found in the bile and 37.6% was found in the urine. At 2 hours after administration, the peak bile-to-plasma OTC concentration ratio was 60:1. Bioavailability of OTC was 47.6% when it was administered orally to fasted turkeys and was 9.4% when administered to fed turkeys.

The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P < 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P < 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P < 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.

An in vitro bioassay system was used to study the effects of cyclopiazonic acid (CPA) mycotoxin on cardiac muscle. Acute exposure to 6 microgram of CPA/ml of modified Krebs-Henseleit solution significantly (P < 0.05) decreased 5 in vitro turkey cardiac muscle performance criteria: maximal weight a muscle could lift; maximal contraction velocity; relaxation velocity; time to peak contraction; and total time for muscle contraction and relaxation. The effect on these 5 criteria appeared to result from intracellular changes partially associated with calcium availability and were irreversible, suggesting that physiologic changes had developed after acute exposure to CPA.

The ability of Mycoplasma hyopneumoniae to agglutinate RBC was evaluated to develop an in vitro cytadsorption assay. Using swine RBC in a microtitration hemagglutination test, no agglutination or partial agglutination was detected. Comparison of RBC from various other species indicated that improved hemagglutination was obtained with RBC from turkeys. This hemagglutination was detected only when mycoplasma cells used in the assay had been frozen and thawed, heated at 50 C for 30 minutes, or treated with trypsin. Treatment of RBC with trypsin or neuraminidase enhanced hemagglutination. Possible surface lectin activity in M hyopneumoniae was evaluated by use of carbohydrates in a blocking assay; hemagglutination was not inhibited by any of 13 carbohydrates evaluated. Mycoplasma hyopneumoniae convalescent porcine serum and monoclonal antibodies against 2 M hyopneumoniae immunogens of molecular weights of 64,000 and 41,000 inhibited hemagglutination.

In the conditions of the Republic of Belarus there were analyzed the peculiar features of morphology of bursa of Fabricius of turkeys broad-breasted white turkeys at the stage of postnatal ontogenesis. Research results showed that postnatal ontogenesis of bursa of Fabricius of turkeys developed irregularly with preservation of organ up to 220 days. At turkeys in 300-day old age the organ preserved only in 45% of bird units. Form, colour and consistency of bursa of Fabricius depended on bird age. The absolute weight of the organ increased up to 220 days. The relative weight was maximum at 20-day old age. The sexual peculiar features of the organ morphology were insignificant; they revealed after the beginning of sexual maturity and expressed by some difference in weight and linear dimensions.

There was studied the features of intra-bodies vessels of turkey thymus of white breed during postnatal ontogenesis. Results of the anatomic and histologic research which allowed to study law of transformations of intra-bodies vessels of turkey thymus are reflected. It is established, that age reorganisation of intra-bodies vessels of turkey thymus is interfaced to development of the basic structural body components. The microvascular thymus channel at the expense of presence hemato-thymus barrier accepts active participation in separation of blood and blood-groove regulation in parenchyma. The maximum factor of thymus blood supply of turkeys is noted in 70 days. Before puberty there is a growth of intra-bodies vessels at the expense of increase in their diameter and a thickness of a wall (mainly media), and after 220 days the haemodynamic potential of body decreases owing to increase of the involutional processes characterized by reduction of vesseldiameter and a thickening of their wall for the account of adventition. In the tabular form the sizes of intracapsular thymic vessels, the sizes of interlobular thymic vessels are presented. | Цель исследования - изучить особенности интраорганных сосудов тимуса индеек белой широкогрудой породы в постнатальном онтогенезе. Отражены результаты анатомических и гистологических исследований, позволивших изучить закономерности преобразований интраорганных артерий тимуса индеек белой породы в период постнатапьного онтогенеза. Установлено, что возрастная перестройка интраорганных артерий тимуса индеек сопряжена с развитием основных структурных компонентов органа. Микрососудистое русло тимуса за счет присутствия гематотимусного барьера принимает активное участие в сепарации крови и регуляции кровотока в паренхиме. Максимальный коэффициент кровоснабжения тимуса индеек отмечен в 70 суток. До полового созревания происходит рост интраоганных артерий за счет увеличения их диаметра и толщины стенки (преимущественно медии), а после 220 суток гемодинамический потенциал органа снижается вследствие нарастания инволюционных процессов, характеризующихся уменьшением диаметра артерий и утолщением их стенки за счет адвентиции. В табличной форме представлены размеры интракапсулярных артерий тимуса, размеры междольковых артерий тимуса.

There were studied the architectonics features of extra-bodies turkey thymic vessels during postnatal ontogenesis. Results of anatomic research of sources of blood supply turkey thymus during the period of postnatal ontogenesis are reflected. Thus, blood supply of turkey thymus is carried out from pair spinal trunk and its branches. The scheme of topographical architectonics of vessels remains on an extent of postnatal developments. Blood supply of the segments laying in a phrenic cavity, is carried out by the branches departing directly from spinal trunk, and the segments located in the field of a neck, from corresponding ascending to a cervical artery. For the vessels departing from a trunk in the phrenic cavity, and also for large vessels of a neck area, the greatest intensity of growth of diameter in the first month of a life is characteristic. With the years there is an increase in diameter of spinal trunk and an ascending cervical artery on 88,14% and 88,89% accordingly. Diameter of the branches going to the first segment, increases till 70 days (by 86,86%), the second and the third - till 110 days (on 82,00%), to large segments - till 220 days (on the average on 72,50%). Reduction of diameter of arteries, blood supplying of thymus segments, located in the field of a neck, after 110 days (on the average on 45,72%) is revealed. It specifies in decreasing of level of their thymus blood supply owing to increase of age involution processes. | Цель исследования - изучить особенности архитектоники экстраорганных артерий тимуса индеек белой широкогрудой породы в постнатальном онтогенезе. Отражены результаты анатомических исследований источников кровоснабжения тимуса индеек в период постнатального онтогенеза. Таким образом, кровоснабжение тимуса индеек осуществляется от парного соннопозвоночного ствола и его ветвей. Схема топографической архитектоники сосудов сохраняется на протяжении постнатального развития. Кровоснабжение долек, лежащих в грудобрюшной полости, осуществляется ветвями, отходящими непосредственно от соннопозвоночного ствола, а долек, расположенных в области шеи, от соответствующей восходящий шейной артерии. Для сосудов, отходящих от ствола в грудобрюшной полости, а также для крупных сосудов области шеи, характерна наибольшая интенсивность роста диаметра в первый месяц жизни. С возрастом происходит увеличение диаметра соннопозвоночного ствола и восходящей шейной артерии на 88,14% и 88,89% соответственно. Диаметр же ветвей, идущих к первой дольке, увеличивается до 70 суток (на 86,86%), второй и третьей - до 110 суток (на 82,00%), к крупным долькам - до 220 суток (в среднем на 72,50%). Выявлено уменьшение диаметра артерий, кровоснабжающих дольки тимуса, расположенные в области шеи, после 110 суток (в среднем на 45,72%). Это указывает на уменьшение уровня их кровоснабжения тимуса вследствие нарастания процессов возрастной инволюции.