Haematology and blood-chemistry for predicting abscesses and other abnormalities in slaughtered pigs

Blood values of slaughtered pigs were determined in an attempt to relate the blood profile with the prevalence of abscesses. To this end 319 pigs were selected and grouped into classes on the basis of pathological ante- and post-mortem findings. The classes thus distinguished were (i) no pathology, (ii) pleurisy or pneumonia and (iii) abscesses occurring singly, metastasised or in combination with other abnormalities. By stepwise discriminant analysis it was established that the blood variables ln(fibrinogen) and albumin were particularly suitable for the detection of abscesses in slaughtered pigs. In this way a correct classification of 89.3% of affected pigs is possible. The numbers of false-positives and false-negatives were 19.3% and 10.7%, respectively. For meat-inspection purposes application of blood analyses is promising. For application in meat-inspection practice rapid on-line methods need to be devised.     

Effect of light intensity on stamen development in the strawberry cultivar‘Glasa’

In forcing the strawberry cultivar ‘Glasa’ under poor light conditions in the glasshouse, a sharp drop in light intensity, leading to a low light level for some days, resulted in stamen abortion in those flower buds which were due to open in a few days. This in turn led to poor fruit set.Under controlled light conditions stamen abortion was found to occur when the light intensity dropped to 4400 mW/m² or less.     

Effect of chilling on runner formation and flower initiation in the everbearing strawberry

Fresh and cold-stored plants of the everbearers ‘Rabunda’ and ‘Ostara’ were placed for 90 days, from the end of August, in glasshouses of the IVT phytotron at 14, 20 and 26°C and a daylength of 16 hours.In the fresh plants hardly any runners were formed at 14 and 20°C, but flowers were initiated, while at 26°C both runners were formed and flowers initiated. In the cold-stored plants, runners were formed first and thereafter flowers were initiated at all temperatures.It was concluded that (1) chilling induces runner formation, but can be replaced by high temperature, and (2) chilling delays flower initiation.     

Evaluation of the immune response induced by intradermal vaccination by using a needle-less system in comparison with the intramuscular route in conventional pigs

The immune response induced by intradermal vaccination using a needle-less device was evaluated in conventional pigs in comparison with the more conventional intramuscular vaccination; to this purpose, vaccination against Aujeszky’s Disease (AD) was used as a model of antiviral immunity. Two groups of pigs (n = 10 each) were vaccinated 4 weeks apart respectively by the intramuscular (IM group) and intradermal route (ID group; needle-less I.D.A.L.® vaccinator) with an AD modified live virus. Ten pigs injected with the vaccine adjuvant only were kept as sham-vaccinated controls (C group).On blood samples collected at 0, 2, 4, 5, 6 and 7 weeks post-vaccination (PV) ADV-specific virus neutralizing (VN) antibodies, IFN-γ secreting cells (SC), lymphocyte subsets and IFN-γ gene expression in PBMC were evaluated.VN antibodies increased after the 1st vaccination and peaked after the 2nd vaccination in both vaccinated groups. Also IFN-γ SC reached maximum levels in both groups after administration of the booster dose. Pigs in the control group remained negative for both parameters throughout the study. Flow cytometry showed persistently higher levels of CD3−CD8α+ Natural Killer cells in both vaccinated pigs. The ID group showed an earlier and regulated activation characterized by an increase of cytotoxic CD8β+ T lymphocytes and CD25+ cells after the boosting dose. No statistically significant differences between treated and control groups were detected for memory CD4+CD8α+^low T cells. Upregulation of IFN-γ gene expression in PBMC was detected in ID and IM pigs after both vaccine administrations, although at a different extent. Overall, the results showed that the intradermal vaccine delivery by a needle-less device can prime a strong humoral and cellular immune response comparable to that obtained by the intramuscular vaccination.     

Some effects of the photoperiod on the shoot growth of cherry seedlings

Summary For cherry breeding it may be of importance to know the factors affecting the growth and development of cherry seedlings. Since it is known from the literature that the photoperiod is an important factor in the annual growth cycle in woody plants, experiments on the influence of the photoperiod were started in the phytotron of our Institute.The effect of 8 and 16-hr. photoperiods on the shoot growth of first- and second-year seedlings of Limburgse boskriek (P. avium L.) was studied at a constant temperature of 20°C. In one experiment the influence of a 24-hr. photoperiod in second-year seedlings was also studied.It was found that under the conditions of these experiments first- and second-year cherry seedlings respond differently to the photoperiod as regards termination of shoot growth. In first-year seedlings many of the plants under 8 and 16-hr. photoperiods terminated their growth at the same time. However, some of the plants under an 8-hr. photoperiod terminated growth much sooner, while a number of plants grown under a 16-hr. photoperiod terminated their growth considerably later. In second-year seedlings growth was terminated at about the same time under 8, 16 and 24-hr. photoperiods.     

Runner formation on strawberry plants in autumn and winter

Summary The present experiments with runner plants of the strawberry variety Deutsch Evern are part of an investigation carried out to determine the conditions under which runners are produced in autumn and winter. This information is necessary to produce runners on mother plants of strawberry selections which are tested for viruses during these seasons.In this paper the influence of increasing the light intensity during the day or the intensity of the additional light, or both, on runner production under a 16 hr day was studied at 17°, 20° and 23°C.It was found that at 20° and 23°C more runners were produced by increasing the light intensity during the day or the intensity of the additional light, or both. But increasing the light intensity produced the best results at 23°C. At that temperature there was a decline in runner production in December and January, if only the light intensity during the day or the intensity of the additional light had been increased. This was hardly the case when both light intensities had been increased.     

Temperature Resistance of Xylanase Inhibitors and the Presence of Grain‐Associated Xylanases Affect the Activity of Exogenous Xylanases Added to Pelleted Wheat‐Based Feeds

The addition of exogenous xylanases (EX‐XYL) to wheat‐based poultry feeds is a common practice today. Wheat contains xylanase inhibitors (XI) and grain‐associated xylanases (GA‐XYL), which could affect the action of the EX‐XYL. In this study, both GA‐XYL and XI activity in feeding‐quality wheat were assessed. In addition, the effect of the conditions during digestion in monogastrics and the effects of pelleting at different conditioning temperatures on GA‐XYL and XI were investigated. The GA‐XYL activity varied between no activity and 0.821 XU/g. In contrast, the XI activity was consistently high in all wheat samples and ranged between 259 and 331 IU/g. Simulating the digestive process did not affect the activities of GA‐XYL or XI. Pelleting at 85°C or higher reduced the XI activity up to 46%. GA‐XYL, however, were more heat‐sensitive, and their activity was reduced to 67% at 60°C. The extract viscosity increased and the release of reducing sugars decreased at higher conditioning temperatures. In addition, the net effect of EX‐XYL on extract viscosity increased at higher temperatures, whereas the release of reducing sugars was not affected. In conclusion, XI affected the action of EX‐XYL during the digestive process, and pelleting did not eliminate their negative effects.