Die Aufforstungen der ungarischen Flugsandgebiete

Ohne Zusammenfassung     

Suppression of neutrophil and lymphocyte function induced by a vaccinal strain of bovine viral diarrhea virus with and without the administration of ACTH

Effects of a modified live vaccine (MLV) strain of bovine viral diarrhea virus (BVD) on lymphocyte and neutrophil function were determined in cattle with and without increased plasma cortisol (hydrocortisone) concentrations. Cattle were given MLV-BVD vaccine IM and intranasally. Cattle given ACTH received 200 IU every 12 hours for 10 doses. The MLV-BVD virus when administered alone caused no apparent clinical signs or body temperature response. Of 4 MLV-BVD-treated calves that were also given ACTH, 2 developed increased body temperature and respiratory distress. The MLV-BVD virus caused a decrease in circulating lymphocytes and neutrophils, whereas administration of ACTH and MLV-BVD induced a neutrophilia and lymphopenia. The MLV-BVD virus and ACTH when administered separately or in combination caused a depression of lymphocyte blastogenesis in response to selected mitogens. Neutrophils were separated from the peripheral blood and their function was evaluated, using the following procedures: (i) random migration under agarose, (ii) ingestion of 125I-labeled Staphylococcus aureus, (iii) quantitative nitroblue tetrazolium reduction, (iv) iodination, and (v) antibody-dependent cell-mediated cytotoxicity (ADCC). The MLV-BVD virus produced a significant (P less than 0.05) suppression of neutrophil iodination and ADCC. Neutrophils from cattle given MLV-BVD virus and ACTH had enhanced random migration, enhanced S aureus ingestion, suppressed iodination, and suppressed ADCC activity.     

Evaluation of bovine polymorphonuclear leukocyte function

Bovine polymorphonuclear leukocytes (PMNs) were isolated from the peripheral blood of cattle. Five in vitro procedures were utilized to evaluate PMN function: 1) Random migration under agarose, 2) Ingestion of ¹²⁵I-iododeoxyuridine labeled $\text{Staphylococcus aureus}$, 3) Quantitative nitroblue tetrazolium reduction, 4) Chemiluminescence and 5) Iodination. Normal values for bovine PMNs are reported and interpretation of results is discussed. The PMN function tests were designed so that all 5 procedures may be performed in a short period of time on the same cell preparation. This allows for the detection and partial characterization of a potential PMN dysfunction.     

Heat Stress, the Follicle, and Its Enclosed Oocyte: Mechanisms and Potential Strategies to Improve Fertility in Dairy Cows

Reduced reproductive performance of lactating cows during the summer is associated with decreased thermoregulatory competence due to intensive genetic selection for high milk production. This review examines the immediate and delayed effects of heat stress on follicular function and describes some potential strategies for their alleviation. It focuses on how heat stress affects the follicle and its enclosed oocyte, suggesting that perturbations in the follicular microenvironment, to which the oocytes are exposed for long periods of development, reduce their developmental competence. Among the potential alterations are reduction in gonadotropin secretion, alteration in follicular growth, attenuation of dominance, and disruption of steroidogenesis. Evaporative cooling methods are the most common strategy used to alleviate the effect of heat stress; however, there is a compelling need to find additional ways to improve fertility during the summer and autumn. Hormonal treatment to enhance removal of the impaired follicles by synchronization of follicular waves with GnRH and PGF2α is suggested. An alternative method is stimulation of follicular growth by a brief treatment with bST or FSH. Other strategies, such as timed AI and embryo transfer, have been recently used, making the optimization of embryo cryopreservation procedures highly relevant. Protection of the ovarian pool of oocytes from thermal stress via nutritional manipulations or administration of antioxidants or other survival factors should also be considered. A better understanding of the underlying mechanisms by which heat stress impairs fertility may lead to the development of additional approaches to alleviate these effects.     

Short-term effect of dietary yeast nucleotide supplementation on small intestinal enzyme activities, bacterial populations and metabolites and ileal nutrient digestibilities in newly weaned pigs

In previous studies, dietary nucleotides have been shown to improve performance in single-stomached animals by promoting the renewal of small intestine epithelial cells and by influencing the activity and composition of the microbial community in the digestive tract. The present experiment was carried out with 12 barrows weaned at the age of 18 days and fitted with a simple T-cannula at the distal ileum. To determine short-term effects of dietary yeast nucleotides, the piglets received a grain-soybean meal-based basal diet with or without supplementation of 1 g/kg of a dried yeast product containing free nucleotides. Dietary supplementation with yeast did not affect bacterial numbers in the ileum as well as ileal concentrations of individual short-chain fatty acids (SCFA), total SCFA and total lactic acid (p > 0.05). Moreover, there was no effect of supplemental yeast nucleotides on ileal α-amylase, leucine amino peptidase, maltase and lactase activities (p > 0.05), as well as on ileal dry matter, crude protein and crude fibre digestibilities (p > 0.05). In conclusion, short-term supplementation with dietary yeast nucleotides did not affect microbial metabolite concentrations, bacterial numbers and enzyme activities in the ileal digesta as well as ileal nutrient digestibilities of newly weaned pigs.     

Impact of delphinidin on the maintenance of DNA integrity in human colon carcinoma cells

Delphinidin has been found to possess DNA strand-breaking properties in cell culture. In the present study, we demonstrated that the extent of DNA damage by delphinidin is not affected by the expression of tyrosyl-DNA-phosphodiesterase 1, indicating that the induction of DNA strand breaks is not predominantly topoisomerase-mediated. However, the DNA-damaging properties of delphinidin were decreased by the addition of catalase to the cell culture medium, counteracting delphinidin-mediated hydrogen peroxide formation. Under these conditions, delphinidin showed clearly antioxidative properties in HT29 cells, preventing menadione-induced oxidative DNA damage. In contrast, in the absence of catalase, delphinidin lacked antioxidative properties. In conclusion, delphinidin acted as an effective antioxidant within intact cells if the formation of hydrogen peroxide was prevented. In the absence of catalase, the accumulated hydrogen peroxide appears to play a substantial role for the observed DNA-damaging properties of delphinidin and the apparent lack of antioxidative properties of this anthocyanidin.     

Einfluß von Zinkmangel auf den Zink-, Protein-, Fett- und Energieansatz von zwangsernährten Ratten

Uber eine Schlundsonde wurden junge männliche Ratten (110 ± 5 g) bei zwei unterschiedlichen Futterniveaus entweder mit einer Basisdiät (103 ppm Zn) oder einer Zn-Mangeldiät (1,3 ppm Zn) 4 mal täglich zwangsernährt. Gruppe 1 und 2 erhielten die Basis- bzw. Zn-Mangeldiät in einer Menge von 11,6 g/Tag und Tier (? hohes Futterniveau). Bei Gruppe 3 und 4 wurde die verabreichte Basis- bzw. Mangeldiät auf 8,7 g/Tag und Tier begrenzt (? niedriges Futterniveau). Nach 12 Versuchstagen wurde der Ansatz an Trockensubstanz, Asche, Zink, Rohprotein, Fett und Energie bestimmt. Der Ansatz an Zink, Trockensubstanz, Asche, Rohprotein, Fett und Energie war bei den Ratten neben der Zinkversorgung auch teilweise vom Futterniveau abhängig. Zinkmangel reduzierte den Ansatz an Trockensubstanz und Asche um 38 bzw. 24%, während für Zink sich ein negativer Wert errechnete, was bedeutet, daß mehr Zink ausgeschieden als aus der Nahrung absorbiert wurde. Mangelnde Zinkzufuhr erniedrigte im Durchschnitt den Energie- und Proteinansatz um 40 bzw. 43 %, während der Fettansatz nur bei niedrigem Futterniveau signifikant um 76% reduziert war.