To establish which factors influence performance and bird welfare during a fattening period and to identify those factors to be investigated during routine monitoring of farms by veterinary ...authorities, a questionnaire-based field study was conducted in districts of Lower Saxony, Germany, with the highest density of broiler chickens. Mortality and BW of farms with different stocking densities (≤33, 33.1-39, and >39 kg/m(2)) were investigated. Analyses of 79 farms with 176 stables and 634 fattening periods revealed that flock mortality and BW appeared to be greatly influenced by weather conditions and litter material. In general, it is an advantage to grow broilers under warm weather conditions. However, the longer the fattening period lasts the more important it becomes that the outside weather conditions are not too warm. Therefore, weather conditions should be considered when determining the length of the fattening period, especially before the background of the growing demands of broilers regarding ventilation, absorption of feces by the litter material, and so on. Apart from the length of the fattening period, the weather conditions determine the choice of the litter material, as well. Under cold-humid weather conditions, it is better to use litter material other than wood shavings. In particular in older buildings it is not possible to provide the required conditions, which results in a lower weight gain the longer the fattening period lasts. The study identified differences in the final BW of flocks, which indicate different (farm) management policies. Regardless of the underlying policy, the performance of a fattening period can be improved by optimizing the farm management according to the prevalent conditions. Future routine monitoring, which should be cost effective regarding personnel and finance, should be generally risk based and consider weather conditions, litter material, the age of the building, and the length of the fattening period.
We investigated whether KIT signaling was sufficient to maintain human hematopoietic stem cells in culture or whether, as with murine stem cells, signaling through glycoprotein 130 (gp130) is ...additionally required. Sorted CD34 super(+)CD133 super(+)(CD33/CD38/CD71) super(-) cells from human umbilical cord blood (UCB) were cultured in the presence of combinations of KIT-ligand (KL) and the gp130 stimulating molecule oncostatin M (OSM). We found that OSM increased KL-induced proliferation, which was accompanied by an expansion in numbers of mature progenitors colony-forming cells (CFC, CAFCw2). More primitive progenitors, CAFCw6 and long-term culture-CFC, were not maintained by KL as a single factor. Although addition of OSM did not improve survival, the KL/OSM combination showed improved maintenance of immature progenitors as well as higher CD34 expression. Similarly, both KL and OSM were required to maintain NOD/SCID-repopulating activity. In experiments to investigate the underlying mechanism, we found that extracellular signal-regulated kinase (ERK) and its downstream target p90 ribosomal S6 kinase were activated by KL and downregulated by the inclusion of OSM during stimulation. The p38 mitogen-activated protein kinase (p38 MAPK) was not modulated by either KL or OSM. Indeed, many of the effects of OSM (increased cell division, maintenance of CFC, and maintenance of high CD34 expression) could be mimicked by using the mitogen-activated protein kinase kinase inhibitor U0126. More importantly, NOD/SCID-repopulating activity was preserved in the KL/U0126-stimulated cells, but not in cells stimulated with a combination of KL and the p38 MAPK inhibitor SB203580. Our results show that the loss of repopulating activity during KL stimulation is counteracted by OSM through the downregulation of ERK pathway signaling. Disclosure of potential conflicts of interest is found at the end of this article.
Schnapp' den Köder: Protein‐Interaktions‐Arrays wurden in lebenden Zellen aus Köder‐präsentierenden künstlichen Rezeptorkonstrukten (Köder‐PARCs) und mikrometergroßen Antikörper‐Oberflächenmustern ...erzeugt (siehe Bild). Mit diesen Arrays konnte gleichzeitig die Kinetik der Wechselwirkung eines Beute‐Proteins mit zwei verschiedenen Köder‐Proteinen in einzelnen lebenden Zellen verfolgt werden.
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